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NEET Biology Biodiversity and Wildlife Conservation Biodiversity. (Gk-Bios = Life; Diversity = Form)

It is the occurrence of different kinds of organisms and the complete range of varieties adapted to different climates, environments and areas being constituents of food chains and food webs of biotic interrelationship. Biodiversity refers to the totality of genes, species and ecosystems of a regi4n.

Biodiversity differs from place to place. As there is a continuous loss of biodiversity due to increasing population, resource consumption, urbanization and pollution, it is important to conserve it.

The basic reason for concern is that biodiversity is being lost even before it attains its size. Loss of biodiversity would check the evolutionary capability of biota to cope with an environmental loss.

Genetic Diversity. All living organisms store genetic information and functions according to the information coded in genes.

• Genetic diversity refers to the variation of genes within species. The differences could be in alleles (different variants of the same genes), in entire genes (the traits determining particular characteristics) or in chromosomal structures.
• Genetic diversity enables a population to adapt to its environment and to respond to natural selection. If a species has more genetic diversity, it can adapt better to the changed environmental conditions. Lower diversity in a species leads to uniformity, as is the case with large monocultures of genetically similar crop plants.
• This has an advantage when increased crop production is a consideration, but can be a problem when an insect or a fungal disease attacks the field and poses a threat to the whole crop.

NEET Biology Biodiversity And Wildlife Conservation Notes

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Species Diversity. The diversity includes the whole range of organisms found on earth. The number of identified species worldwide is between 1-7 and 1-8 million. However, the estimates of the total known species maybe 50 million. A large number of plant and animal species are yet to be identified. There are many more species to be present in the tropics.

Importance Of Species Diversity To Ecosystem:

Ecologists believe that communities with more species tend to be more stable than those with fewer species.

A stable community has the following attributes.

1. It shall not show too much of variations in the year-to-year productivity.
2. It must be either resistant or resilient to seasonal disturbances.
3. It must be resistant also to invasion by alien species.

David Tilman had shown through his ecology experiments using outdoor plots, the following features.

1. The plots with more species showed less year-to-year variation in the total biomass.
2. Plots with increased diversity showed higher productivity.

Global Biodiversity

• According to IUCN (2004), the total number of plant and animal species described is about 1.5 million.
• The species inventories for taxonomic groups in temperate countries/regions is more complete than those in tropical countries/regions.
• A more conservative and scientifically sound estimate has been made by Robert May; it puts the global species diversity at about seven million.
• More than 70% of all the species recorded are animals and plants account for about 22%; 70% of the animals are insects.

NEET Biology Biodiversity And Wildlife Conservation Notes

Biodiversity And Wildlife Conservation NEET Notes

These Estimates Do Not Give Any Figure For Prokaryotes For The Following Reactions:

1. The conventional taxonomic methods are not suitable/sufficient for identifying these microbial species.
2. Many of these species cannot be cultured under laboratory conditions.
3. Biochemical and molecular biology techniques would put their diversity into millions.

Ecosystem Diversity: Species are distinct units of diversity, each playing a specific role in the ecosystem.

• Diversity at the level of community and ecosystem has three perspectives i.e. Alpha, Beta and Gamma diversity.
• Ecosystem diversity describes the number of niches, trophic levels and other ecological processes that maintain energy flow, food webs and recycling of nutrients.

The Three Perspectives Of Diversity At the Level Of Community And Ecosystem Are:

1. Alpha diversity
2. Beta diversity and
3. Gamma diversity.

1. Alpha Diversity. It refers to the diversity of organisms sharing the same community. It has been found that there is an increase in diversity with a decrease in latitude.
2. Beta Diversity. The rate of replacement of species along a gradient of habitat or communities is called beta diversity.
3. Gamma Diversity. It is the rate at which additional species are found as replacements in different localities of the same habitat.

Gradients Of Biodiversity: Biodiversity varies with changes in latitude or altitude. As we move from high to low latitudes (i.e., from the poles to the equator), broadly speaking, the biological diversity increases.

• In the temperate region, the climate is severe with short growing periods for plants. In tropical rainforests, the conditions are favourable for growth throughout the year.
• Favourable environmental conditions favour speciation and make it possible for a larger number of species to occur and grow.
• For example, the mean number of vascular species per 0-1 ha sample area in tropical rain forests varies from 118-236, whereas it is only in the range of 21-48 species in the temperate zones.
• Latitudinal and altitudinal gradients of species diversity are two master gradients of biodivorsity.

NEET Biodiversity And Wildlife Conservation Chapter Notes

Patterns Of Biodiversity

• Biodiversity is not uniform throughout the world but varies with changes in latitude and attitude.
• Favourable environmental conditions favour speciation and make it possible for a large number of species to exist there; i.e. biodiversity is more in such areas than in others.

1. Latitudinal Gradients
   • Species diversity decreases from the equator towards the poles.
   • The tropics (between 23.5° N to 23.5°S) harbour more species than temperate and polar regions.
   • For example. Columbia situated near the equator, has about 1400 species of birds, while New York (41°N) has 105 species. Greenland (71°N) has about 56 species and India (in the equator region’) has 1200 species.
   • The number of species of vascular plants in the tropics is about ten times more than that of temperate forests.
   • The Amazonian rain forest in South America has the greatest biodiversity on earth; it harbours about 40000 species of plants. 1.25.000 species of insects. 3000 of fishes, 427 of amphibians, 3.78 of reptiles. 1300 of birds and 427 of mammals.
2. Species-Area relationship
   • Alexander Von Humboldt has observed that within a region, species richness increased with increased explored area, but only up to a limit.
   • The relationship between species richness and area for a number of taxa like angiospermic plants, freshwater fishes and birds is found to be a rectangular hyperbola.
   • On a log scale, the relationship becomes linear (straight line) and is described by the equation.

log S = log C + Z log A.

where, S = Species Richness Z = slope of a line (regression coefficient)

A = area and C = y-intercept

Ecologists have found that the value of the Z-line ranges between 0.1 and 0. irrespective of the taxonomic group or the region.

But in this analysis in very large areas like a continent, the Z-value ranges between 0.6 and 1.2.

The Z value for frugivorous birds and mammals in tropical forests is found to be 1.15.

Biodiversity And Wildlife Conservation NEET Notes

Use Of Biodiversity In Agriculture

1. As a source of new crops.
2. As a source material for breeding varieties.
3. As a source of new biodegradable pesticides.

Only 20% of total plant species are cultivated to produce 85% of the world’s food.

Wheat, com and rice, the three major carbohydrate crops, yield nearly two-thirds of the food sustaining the human population. Fats, oils, fibres, etc. are other uses for which more and more new species need to be investigated.

Drugs And Medicines From Biodiversity:

Numerous significant medications have derived from botanical sources.

• Examples of plant-derived compounds transformed into important pharmaceuticals include
• Morphine (Papaver somniferum), utilized as an analgesic; Quinine (Chinchona ledgeriana), employed in malaria treatment; and Taxol, an anticancer agent synthesized from the bark of the yew tree (Taxus brevifolia, T. baccata).
• Presently, 25% of the pharmaceuticals in the pharmacy originate from only 120 plant species.
• However, globally, traditional medicines utilize thousands of plant species.
• Plants can also be utilized in the production of countless synthetic goods known as botanochemicals.

Aesthetic And Cultural Benefits From Biodiversity:

Examples of aesthetic rewards include ecotourism, bird watching, wildlife, pet-keeping, gardening etc. Throughout human history, people have related biodiversity to the very existence of the human race through cultural and religious beliefs.

Biodiversity Is Essential For The Maintenance And Sustainable Utilization of goods and services from ecological systems as well as from individual species.

NEET Biodiversity And Wildlife Conservation Chapter Notes

Causes Of Loss Of Biodiversity: Biological diversity is lost before its size is known.

1. Increased human population.
2. Consumption of resources.
3. Pollution due to human activities.

Consequences Of Loss Of Biodiversity

1. It would check the evolutionary capability of biota to cope with environmental changes.
2. It would result in the extinction of species.
3. As man is dependent on food and other necessities, its loss will be hard-pressed for mankind.

Threats To Biodiversity: Important factors leading to extinction of species and consequent loss of biodiversity are

1. Habitat Loss And Fragmentation
   • It is the most important or primary cause of extinction.
   • The tropical rain forests initially covered 14% of the land surface of the earth, but now they cover only 6% of the land area.
   • The Amazonian forests, called the ‘Lungs of the planet’, are cleared for cultivation of soyabean or conversion into grasslands for raising beef cattle.
   • Total loss of a habitat deprives many animals and plants of their homes and they face extinction
   • Degradation of habitats by pollution threatens the survival of many species.
   • When a large habitat becomes fragmented, animals requiring large territories and those with certain migratory habits are adversely affected and their populations start decreasing.
2. Introduction Of Exotic Species Leading To Endangering The Species: Exotic species are having a large impact, especially in island ecosystems, which harbour much of the world’s threatened biodiversity. A few examples are
   • Nile perch, an exotic predatory fish introduced into Lake Victoria (South Africa) threatens the entire ecosystem of the lake by eliminating several native species of the small Cichlid fish species that were endemic to this freshwater aquatic system.
   • Water hyacinth clogs rivers and lakes and threatens the survival of many aquatic species in lakes and river flood plains in several tropical countries including India.
   • Lantana camara has invaded many forest lands in different parts of India and strongly competes with the native species.
3. Over-exploitation of soil, water,
4. Atmospheric pollution and
5. Intensive agriculture and forestry.

Biodiversity And Wildlife Conservation Class 12 Notes For NEET

Protected Areas: These areas are land or sea dedicated to the protection and maintenance of biological diversity. They include National parks. Sanctuaries and Biosphere Reserve. As of Sept. 2002. India has 581 protected areas.

• National Parks. A national park is an area which is strictly reserved for the betterment of wildlife and where activities like forestry, grazing or cultivation are not permitted. In these parks, even private ownership rights are not allowed.
• Sanctuaries. A sanctuary is a protected area which is reserved for the conservation of only animals and human activities like harvesting of timber, and collection of minor forest products and private ownership is allowed so long as they do not interfere with well well-being of animals.
• A biosphere reserve is a specified area in which multiple use of the land is permitted by dividing it into certain zones, each zone being specified for a particular activity.

Biosphere Reserve: A biosphere reserve is a specified protected area of land and/or coastal environment in which multiple use of the land is permitted by dividing it into zones, each for a particular activity.

Types Of Biodiversity NEET Biology

Recently, the concept of Biosphere Reserve has been evolved by UNESCO’s Man and Biosphere Programme (MABP). Till May 2002, there are 408 biosphere reserves located in 94 countries out of which 13 are in India. Of these, the Nilgiri Biosphere Reserve was declared in 1986.

Zones of Biosphere Reserve. A biosphere reserve is divided into three zones: core, buffer and manipulation.

1. Core Zone. No human activity is allowed in the core zone.
2. Buffer Zone. Limited human activity is permitted in the buffer zone.
3. Manipulation Zone. Several human activities can occur in the manipulation zone.

Types Of Biodiversity NEET Biology

Role of a Biosphere Reserve. A biosphere reserve preserves

1. Conservation of wild populations,
2. Development, and
3. Genetic resources of domesticated plants and animals carrying out scientific research monitoring and education.

Benefits Of Protected Areas

1. Maintaining viable populations of all native species and subspecies.
2. Maintaining the number and distribution of communities and habitats, and conserving the genetic diversity of all the present species.
3. Preventing human-caused introduction of alien species.
4. Making it possible for species/habitats to shift in response to changes in the environment.

Ex-situ Conservationhttps://learnmpbse.com/neet-biology-organisms-and-population-ageing-and-death-notes/. It means maintenance of offsite collections either in gardens by farmers, and botanical gardens or storing seeds, genes, pollen, tissue culture etc.

• The rare plants have been found to flourish in large numbers under the care and protection of gardeners and nature lovers.
• Farmers have been maintaining genetic diversity (enormous varieties) of crop plants since ancient times by saving seeds or other components for the next plantings.
• Collection of samples of cultivated and wild varieties of plants and storing them in botanical gardens is another method of conservation of germplasm.
• In seeds, the living material remains in a metabolically suspended state. When the seeds are to be stored for longer periods, it is necessary to avoid conditions which favour respiration and enzymatic action.

Hot Spots Of Biodiversity: The concept of ‘Hot-spots’ was developed by Norman Myers (1988) to designate specific areas for in-situ conservation. The hot spots are the richest and most threatened reservoirs of plant and animal life on earth.

NEET Biology Biodiversity And Wildlife Conservation Important Points

The Criteria For Determining Hot Spots Are:

1. Number of endemic species.
2. Degree of threat which is measured in terms of habitat loss.

There are 25 hot spots in the world out of which two are in India. They are the Western Ghats and Eastern Himalayas.

Hot spots of the Eastern Himalayas are active centres of evolution and rich in diversity of flowering angiosperms. Western Ghats have semi-evergreen forests. The Western Ghats include two main centres of biodiversity i.e., Aqastyamalai Hills and Silent Valley.

IUCN Red List. It is a catalogue of taxa that are facing the risk of extinction. The uses of the red list are

1. Developing awareness, about the threat of loss of biodiversity
2. Identification and documentation of endangered species.
3. Providing a global index of the decline of biodiversity.
4. Defining conservation.

IUCN Red List Categories

NEET Biology Biodiversity and Wildlife Conservation Natural Resources

Natural Resources are components of the biosphere and include energy, air, land, water, minerals, plants, animals and microorganisms.

As a result of manipulation by man, the biosphere has become transformed into a human-dominated environment called Noosphere (noo = mind, sphere = domain).

Natural Resources Are Categorised As Follows:

Depending on the availability and abundance the natural resources are classified into the following kinds

1. Inexhaustible Resources. These resources are not likely to be exhausted by man’s consumption and other uses. They are, for example, wind, tidal energy and precipitation.
2. Exhaustible Resources. These are the resources which are likely to be exhausted by man’s consumption.

Kinds of natural resources based on renewability

1. Renewable Resources. These resources are naturally replenished after man’s consumption. They have the inherent capacity to reappear by quick recycling. They are water, wood, soil, natural pastures living organisms etc.
2. Non-Renewable Resources. The resources that cannot be replaced faster than they are used. They are fossil fuels and mineral ores.

Kinds Of Natural Resources Based On Composition

There Are Three Types On The Basis Of The Ownership.

• Other direct sources of energy are sunlight, hydroelectric and wind power, tidal energy, and nuclear and geothermal energy.
• Presently, the major energy sources arc fuel wood and fossil fuels (coal, petroleum and natural gas).
• Per capita energy consumption per day in the U.S.A. has reached 2,50,000 keal. It is as low as 10,000 kcal in developing countries.
• Thirty per cent of the world’s population, living in industrialized countries, consume about 80% of total global energy.

NEET Biology Biodiversity and Wildlife Conservation Type Of Soil Components And Vegetation

Soil. It is a weathered superficial layer of the earth’s crust which is capable of supporting life.

Soil As A Resource. Landforms about 1l/5th of the earth a major constituent of the lithosphere and are the source of many materials, which are used by man.

All the terrestrial plants obtain their water and mineral nutrients from the soil. The yield of all biotic products in terrestrial ecosystems depends upon soil. Numerous microbes (bacteria and fungi) and many animals which are involved in the decomposition process live in the soil. All of them form humus by accumulation of partially synthesised organic materials.

Importance Of Biodiversity Conservation NEET Study Material

Pedology. The branch of science which deals with the study of soil is called pedology.

Origin Of Soil. The processes of soil formation are generally divided into two stages:

1. Weathering. The breakdown of bigger rocks into fine mineral particles is called weathering. It is mostly a physical or chemical process.
   • Chemical Weathering. It is caused by oxidation, hydrolysis or carbonation.
   • Mechanical Weathering. It is caused by living organisms, for example, lichens, grazing animals or earthworms.
2. Pedogenesis Or Soil Development (Soil Maturation). It is a constructive biochemical process which converts the disintegrated mass of rock particles into mature soil. It consists of humification, eluviation and illuviation.
   • Humification. The remains of plants and animals undergo decomposition to produce an amorphous colloidal complex called lumens. The process of formation of humus is known as humification.
   • Eluviation And Illuviation. Washing down or leaching the contents of the upper layer of the soil is called eluviation and the decomposition of the contents of the upper layer in the deeper layer is called Illuviation. These two processes go on simultaneously.

1. Sandy Soils: Mainly sand.
2. Clayey Soils: Mainly clay.
3. Loamy Soils: Sand, silt and clay.
4. Sandy Loam Soils: Sand particles are dominating
5. Silt Loam Soils: Silt particles are dominating
6. Clayey Loam Soils: Clay particles are dominating

Types Of Vegetation On The Basis Of Nature Of Soil

1. Rock Soil: Lithophytes
2. Sandy Soil: Psammophytes
3. Humus Or Acidic Soil: Oxylophytes
4. Cold Soil: Psychrophytes
5. Crevices Of Rocks: Chasmophytes
6. Deserts: Gemophytes
7. Saline Or Alkaline: Halophytes

Types Of Soil On The Basis Of Origin

1. Skeletal Or Immature Soil. Partly weathered parental rocks.
2. Residual Soil (Sedentary Soil). Soil exists in the place of their origin.
3. Transported Soil. Shifted to different places.
   1. Alluvial Soils. Transported by the water of rivers.
   2. Colluvial Soils. Shifted due to gravitational force.
   3. Aeolian Soil. Shifted by wind.

Leaching. It is an important factor which makes the soil poor in its resources. In this process, minerals and organic substances are removed from the top layer of soil by rainwater.

Importance Of Biodiversity Conservation NEET Study Material

Biological Agencies. They are also active in causing loss of resources from the soil. Cultivation of soil year after year makes the soil less productive.

Mulching. Use of artificial protective covering having a mixture of wet straws, leaves etc.

• Man-land ratio in India is very low i.e. 0.48 hectare per capita of available land.
• Of the particulate constituents, clay and humus mainly are the determinants for the properties of soil.
• Sand and silt consist largely of quartz (SiO₂), and are chemically inert.

Clay is chemically more active and possesses a high capacity to hold water and ions. Pure clay is not a suitable medium for plant growth, because it forms a solid impenetrable mass. However, if mixed with other constituents of the soil, the charges on the ions link the particles together to form aggregates (or crumbs) to produce granular soil.

Soils without clay particles are structureless, and powdery and are not capable of holding water and nutrients.

Soil Organisms. A large number of organisms occurring in the soil like bacteria, fungi, algae, protozoans, nematodes, insects, earthworms etc. are called soil organisms. The number of earthworms may be as high as 6,00,000 – 79,11,000 per hectare in Indian grassland.

(Dash 1978) Bacteria are the most abundant of all soil organisms (14 million to 58 million/gm.) followed by protozoans (10,000 – 2 million/gm).

These Organisms Play Following Important Roles In The Soil:

1. Nitrogen fixation
2. Mycorrhizal association
3. Soil-borne diseases
4. Decomposition of organic matter.

Humus is formed by the accumulation of partially decayed and partially synthesised organic materials such as cellulose, hemicellulose, lignin, sugar, lipids and proteins. It helps in making the soil granular.

• It causes air spaces to be formed in the clay soil and increases the water-holding capacity of sandy soils. Humus is rich in nutrients and thus enhances plant growth. Being black, humus absorbs heat and warms up the soil.
• Plant debris falling on the ground which is undecomposed is called litter. Broken and partially decomposed organic matter is called duff or more. The organic matter in acidic conditions does not decompose rapidly due to inhibition of microbial activities, this partially decomposed organic matter is called peat or muck.

Importance Of Top Soil: Soil plays a multiple role in the life of organisms

1. It provides water and mineral nutrients to the terrestrial plants.
2. It is the medium in which plant and animal materials are decomposed. The inorganic components, namely CO₂, and H₂O, formed as the end products of decomposition are released into the environment for reuse by plants.
3. It provides a habitat for microbes.

Soil Erosion. In this process, the fertile soil surfaces are detached and deposited at other places.

Agents Of Soil Erosion

1. Water Erosion. This type of soil erosion is caused by water. The raindrops fall on the superficial layers and erosion takes place due to the flow of water.
2. Sheet Erosion. Due to heavy rain, the top fertile soil is removed in the form of a thin sheet.
3. Rill Erosion. Fast-running water cut stream or groove-like structures in soil.
4. Gully Erosion. On steep slopes, fast-running water cuts the soil deep and forms channel-like structures called gullies.
5. Ravine Erosion. During floods fast running water cut off the margins of the river. Due to heavy rains, the minerals are also lost from the topsoil and the soil becomes less fertile.
6. Wind Erosion. In deserts, soil erosion takes place continuously due to wind and cyclones.
7. Land Slides Or Slip Erosion. Due to heavy rains, the edges of hills are washed away and due to gravity, they fall.
8. Stream Bank Erosion. Due to floods, the banks of rivers are eroded.

Principles Of Soil Erosion

1. Normal Or Geological Erosion. This is a slow process. It is a common natural phenomenon. A balance is maintained between formation and erosion.
2. Accelerated Soil Erosion. In this type of erosion, a balance is not maintained between erosion and formation. The speed of erosion is so fast due to man or any other reason that it is impossible to have a similar formation speed. Due to this type of soil erosion man has to face many problems.

Biological Methods Of Soil Conservation

1. Contour agriculture
2. Mulching
3. Crop rotation
4. Dry farming.

Importance Of Biodiversity Conservation NEET Study Material

Restoration Of Soil Fertility

1. The application of biofertilizers is useful in enhancing soil fertility.
2. Various organic farming measures, which provide increased input to soil have long-term beneficial effects on soil futility.

NEET Biology Biodiversity and Wildlife Conservation Sources Of Water

The sources of water on earth are oceans, rivers, lakes, soil moisture and groundwater.

Oceans contain 97% of 14 billion cubic kilometres (km³) of remaining water. Ice in the polar ice caps and permanent glaciers had about 3% of the remaining water. The rest of the water is in the form of water vapours, lakes, rivers and groundwater.

List Of Marine Resources

The global hydrological cycle enables oceans to provide a consistent supply of fresh water for human, animal, and plant utilization.

• The ocean serves as a repository for several compounds involved in biological cycles and various other items.
• Marine vegetation functions as a primary producer.
• Kelp and several marine organisms are utilized as sustenance.
• Iodine and industrial gums are derived from seaweeds.
• Agar is derived from the green algae Gracilaria and Gelidium.
• Algin is extracted from Sargassum and Turbinaria.
• Pearls derived from pearl oysters are utilized as precious adornments.
• Mollusc shells are utilized to produce quicklime.
• Sodium, chloride, magnesium, and bromide are derived from seawater.
• Petroleum and natural gas are extracted from continental shelves.
• The oceans provide as supplies of deuterium, uranium, gold, manganese, iron, lead, and sulfur.

Fresh Water:

Out of the 3%, 77.2% is stored in glaciers and icecaps and 224% is groundwater and soil moisture. The remaining 0.36% is present in lakes, rivers, streams, swamps etc. This fresh water is available for drinking and irrigation purposes. In the atmosphere, there is 0.00 J of water.

Ocean water is also very important for mankind. Man’s direct relation is more with fresh water. Rainfall is due to the evaporation of ocean water and as a result of this fresh water is available. 90% of the total evaporated oceanic water reaches back into the ocean.

Role Of Water In Supporting System:

Water plays a vital role in supporting the system as follows.

1. It has an influence in regulating climate.
2. The ocean acts as a heat bank for coastal regions releasing and absorbing heat.
3. Waterfalls, tides and river currents are used to move machines and generate hydroelectric power.
4. Water is essential for agriculture and industry.
5. It provides a surface for navigation.
6. Water provides the hydrogen required in living systems.

Conservation Of Water Resources:

For the conservation and management of freshwater following methods can be employed

1. Reducing agricultural water wastage by increasing the efficiency of the irrigation system.
2. Afforestation and protection of watersheds to improve economy.
3. Formation of artificial clouds, so that a change can be brought into the atmosphere.
4. Changes in the vegetation of a particular area, so that even in the dry season maximum amount of water can be stored. In addition to this dams should be constructed to stop the drainage of rainwater.
5. Control the distribution of water by constructing big dams.
6. Desalinization of seawater and saline groundwater.
7. Proper utilization of underground water.
8. Attempt to extract minerals from water.
9. Melt the glaciers and snow for use as a freshwater resource.
10. Regular dredging and desolation of water bodies.

Wetlands:

Wetlands are low-lying areas usually covered by shallow water and have characteristic soils and water-tolerant vegetation. Wetlands may be either freshwater or saltwater (coastal). Freshwater wetlands include marshes (where grass-like plants dominate), swamps (where trees or shrubs dominate), and periodically flooded riverine forests found in lowlands along streams.

Wetlands occupy almost 6% of the world’s land surface and provide crucial environmental services. Wetlands are often drained, dredged or filled up for housing and industrial purposes. They are increasingly threatened by agriculture, pollution and engineering constructions (such as dams).

Importance Of Wetlands

1. They serve as groundwater recharge areas.
2. To help clean and purify water runoff.
3. They are highly productive areas.
4. In saltwater wetlands, the mangroves hold sediment and accumulate soil along the shoreline.
5. As mangroves expand into the ocean other plants colonize the soil left behind.

Measures For Salt Water Wetland Conservation: Coastal wetlands are called saltwater wetlands which include highly productive estuaries.

Threats To Biodiversity NEET Exam Preparation

Wetland Conservation:

Wetland conservation programmes are generally based on

1. Preparation of wetland inventories.
2. Identification of wetlands of critical importance for their protection.
3. Checking waste disposal in wetlands.
4. Reduction of excessive inflow of nutrients and silt into wetlands from surrounding uplands by keeping them under plant cover.

NEET Biology Biodiversity and Wildlife Conservation Grasslands

Grasslands, commonly referred to as rangeland, supply feed and shelter for domestic animals and wildlife. In rural regions, dried hay extracted from grasslands, especially from tall grasses, serves as fuel or thatching material.

Grass cover is exceptionally effective in binding soil particles through a densely branching fibrous root system, hence markedly diminishing soil erosion.

• In India, the extent of diverse grass cover, encompassing fallow and wastelands, is approximated to constitute around 18% of the total land area.
• Including the forested region, which constitutes approximately 19% of total land and predominantly facilitates grazing, roughly 37% of land is deemed available for grazing.
• India’s average annual yield of dry grass or hay is approximately 250 million tons.

Degradation of Grassland:

Degradation or destruction of grassland is mainly related to overpopulation. To enhance food production, grasslands possessing fertile soils are ploughed and converted to agricultural lands (for example North American prairies).

In developing countries, grassland areas are frequently overgrazed. For example, the number of animals grazing in the arid and semi-arid regions of India had been found to be 2-10 times greater than the capacity of the grassland to feed the animals.

Management Of Grasslands

1. Protection from grazing
2. Use of rotational grazing
3. Removal of woody bushes or shrubs and weeds.
4. Use of controlled burning to promote recycling of nutrients.
5. Conservation of soil and water by reducing loss of soil and water.

NEET Biology Biodiversity and Wildlife Conservation Forests

A forest is a special biotic community of immense value to the environment and living beings.

• Forests provide a large number of products which are of great economic value such as timber, firewood, bamboo, cane, oils, resins and useful chemicals.
• In India, forests have been reported to cover 22.7% of land (74.8 million hectares).
• Remote sensing surveys have shown forest cover to be about 14%.
• Constitution of Indian forests
  • Tropical dry deciduous forests (38.7%),
  • Tropical moist deciduous forests (30.9%),
  • Tropical thorn (6.9%),
  • Plant sale and teak (13%).
• Forests check soil erosion, control air pollution and provide shelter to a large number of animals.

Conservation of forests involves the extraction of timber and wood on a sustainable basis, replantation of native species on a replaceable basis, and special afforestation programmes.

• The Union and State governments have launched several afforestation programmes.
• The Social Forestry Programme started in 1976, seeks the use of public and common land to produce firewood, fodder, and small timber for the use of the rural community to reduce pressure on existing forests needed for soil and water conservation.

Agroforestry programmes—aim at reviving ancient land use practices (same land used for farming, forestry and animal husbandry).

Urban forestry programme— consists of planting trees for aesthetic purposes in urban areas.

Forest Cover: In India, 74.8 million ha or 22.7% LAPD was under forest cover in 1980 (Central Forestry Commission). It has increased to 75.23 million hectares or 22.96% in 1993. Champion and Seth (1968) have recognised 16 forest types in India. 38.7% area is covered by tropical deciduous forests, 30.9% by tropical moist deciduous forests, 6.9% by tropical thorn, and 13% by Sal and Teak strands.

Threats To Biodiversity NEET Exam Preparation

Biological Methods Of Soil Conservation

1. Contour agriculture
2. Mulching
3. Crop rotation
4. Dry farming.

Restoration Of Soil Fertility

1. The application of biofertilizers is useful in enhancing soil fertility.
2. Various organic farming measures, which provide increased input to soil have long-term beneficial effects on soil fertility.

NEET Biology Biodiversity and Wildlife Conservation Importance Of Forest Resources

Productive Functions

1. Forests Provide Wood. Indian forests yield valuable timber wood like teak, sal, deodar, shisha etc.
2. Forests Provide Paper. The conifers and bamboo are used as raw materials to prepare paper.
3. Medicinal Plants in forests provide medicine of great importance.
4. Forests provide a number of products like resins, gums, rubber, food and insecticides.
5. Forests provide shelter to a variety of animals.
6. Forests also provide the cork for example oak (Quercus)

Protective Functions: Role of forests in the protection of lands. Forests play a vital role in the life and economy of all tribes living in the forests.

1. Forests prevent the erosion of soil by wind and water.
2. Large trees provide shade which prevents the soil from becoming dry and friable during the summer.
3. They check the velocity of raindrops or wind striking the ground and reduce the dislodg¬ing of the soil particles.
4. The root system of plants firmly binds the soil.

Role Of Forests In Retaining Sub-Soil Water: Forests improve the quality of soil by increasing its porosity. The forest soil absorbs water during rains like a giant sponge and does not allow it to evaporate or run off quickly.

It ensures a perennial supply of subsoil water in springs and wells. Thus the hill slopes with vast forest cover in the catchment areas conserve water and gradually release it into streams, rivers and subsoil springs.

Deforestation: According to an estimate; almost 40% of forests have been lost in the tropics and 1% of forests in the temperate region.

• In India, at the beginning of the twentieth century, forests covered about 30% of land whereas by the end of the century, it reduced to 19.4%.
• The National Forests policy (1988) has recommended 33% forest cover for plains and 67% for hills.

Causes For Deforestation.

1. Forests are converted into agricultural lands to feed the growing human population.
2. Forests are cleared for making homes and establishing industries.
3. Trees are felled for timber, firewood, etc.
4. Jhum cultivation in the north-eastern states has contributed to deforestation.

Consequences of Deforestation

1. Carbon dioxide concentration in the atmosphere has increased.
2. There is a loss of biodiversity due to habitat destruction.
3. Deforestation disturbs the hydrological cycle.
4. There is soil erosion and it may lead to desertification in extreme cases.

Forest Conservation: Before man’s evolution, 70% of the land was covered by forests, which is now only 16%. The forests were depleted due to river valley projects, commercial use, agriculture development etc. To stop the destruction of forests, forest management, social forestry and public efforts are also necessary.

Forest management should be such that along with the protection of forests, production should also increase.

Afforestation: Looking at the rapid destruction rate of forests, the National Agriculture Commission started a scheme in 1976 called social forestry. Under this scheme such trees were to be planted which give the fuel wood to the local people, fodder for their animals, tools for agriculture, some teak for making houses and minor forest produce etc.

Many afforestation programmes have been taken in hand by central and state governments.

1. Social Forestry Programme (1976). It requires raising trees for fuel wood, fodder, agricultural implements and fruits on public and common lands for the benefit of rural communities. The programme is aimed at reducing the demand on existing forests needed for soil and water conservation.
2. Agroforestry Programme. It is aimed at reviving the ancient practice of using the same land for farming, forestry and animal husbandry.

Urban Forestry Programme. It is aimed at growing ornamental and fruit trees in urban areas along roads, in private compounds and in common parks.

Threats To Biodiversity NEET Exam Preparation

Ecological Uses

1. Protection of Land. Plant cover protects soil from drastic changes in temperature, action of wind, action of raindrops, holding soil, preventing landslides and making the soil spongy as well as fertile.
2. Retention of Subsoil water. Plant litter and humus prevent run-off, hold water like a sponge and allow percolation, resulting in perennial fresh water through springs.
3. Climate. Moderating and moistening effects
4. Frequency Of Rainfall. Increases. Atmospheric humidity becomes high.
5. Pollution. Forests reduce atmospheric pollution absorbing gases and collecting SPM.
6. Shelter. To wild animals.

NEET Biology Biodiversity and Wildlife Conservation Wild Life

William Hornaday coined the term wildlife when he wrote the book Our Vanishing Wild Life.  Wildlife refers to any living organism in its natural habitat. It includes plants, animals and micro-organisms other than cultivated plants and domesticated animals.

• Wildlife balances the population and maintains the food chain and natural cycle.
• It preserves the environment as a self-sustaining system.
• Wildlife is of great value as a gene bank for feeding programmes in animal husbandry and fishery, which are of great benefit to humans.
• Human activities have hastened the extinction of many species which is otherwise a natural phenomenon.
• The extinction of a species is a part 6f the natural process.
• The destruction of wildlife is on account of food, safety and pleasure; habitat destruction; over-exploitation and international commercial trade.
• The threatened species of plants and animals have been categorised as endangered (E), Vulnerable (V), and Rare (R).
• Conservation is the management of human use of the biosphere so that it may yield the greatest sustainable benefit to the present generation while maintaining its potential to meet the needs and aspirations of future generations.
• For conservation of the wild life rare species of plants and animals have been categorised as endangered, vulnerable and rare according to the degree of danger facing them.
• Steps for conservation of the wildlife include
• Protection of threatened species,
• Preservation of the ecosystem
• Safeguarding of critical habitat.
• Bilateral and multilateral agreements should be made to protect the species whose migratory ranges are over more than one country.

NEET Biology Biodiversity and Wildlife Conservation Concept Of Endangered Species

A species is considered as endangered when its natural regeneration is not able to keep pace with exploitation or destruction by natural and unnatural means.

The International Union for Conservation of Nature and Natural Resources (IUCN) has identified rare species of plants and animals on the following basis:

1. The present and past distribution,
2. The decline in the population in the course of time,
3. Abundance and quality of natural habitat and
4. Biology and potential value of the species.

IUCN has recognised the following categories on the basis given above.

1. Endangered (E). These are the species or taxa facing extinction and whose survival is unlikely if the causal factors continue to operate. The number of these species is reduced to a critical level or whose habitats have been so heavily decreased that they are believed to be in immediate danger of extinction.
2. Vulnerable (V). These are the species which would fall into the category of endangered species in the near future if causal factors continue to operate. The category includes
   • Species of which most or all the populations are decreasing because of over-exploitation, extensive destruction of habitat or other environmental disturbances;
   • Species with populations that have been seriously depleted and whose ultimate security is not yet assured, and
   • Taxa with populations that are still abundant but are under threat from serious adverse factors throughout their range.
3. Rare (R). These are the taxa with small world populations that are not at present endangered or vulnerable but are at risk. These taxa are usually localised within restricted geographical areas or habitats are thinly scattered over a more extensive range.
4. Threatened (T). These are the taxa which fall into any one of the above three categories- endangered, vulnerable and rare. Some species are marked as threatened where it is known that they are endangered, vulnerable or rare but there is not enough information to say which of the three categories is appropriate for them.
5. Out Of Danger (O). These are the taxa which were earlier placed in one of the three above categories but which are now considered relatively secure because of the application of effective conservation methods.
6. Indeterminate (I). These are the taxa suspected of belonging to one of the first three categories but for which insufficient information is currently available.

Endangered Plants: Botanical Survey of India attempted in 1970 to investigate plants belonging to different categories. Under this project, a list of 100 endangered species of plants has been prepared in collaboration with the Forest Research Institute, Dehradun. So far, however, about 900 taxa of plants are listed as endangered or rare in India.

• Estimated number of Plant species: 45,000
• Vascular Plants: 15,000
• Non-flowering plants: 30,000
• No. of species endemic to India: 7,000
• No. of species of ethnobotanical interest: 800
• No. of cultivated species or endemic: 250
• No. of wild forms and relatives of cultivated species: 320

The list of endangered species of plants and animals is given in the Red Data Book. Many countries have prepared their own Red Data Books. Department of Environment, Government of India, has published two volumes of Red Data Book, listing 435 endangered species of plants.

As against the Red Data Book, there is a Green Book. It lists plants grown in protected areas. A Green Book has been prepared, in which hundreds of rare plants have been listed, which are growing in the gardens of the Botanical Survey of India.

In-Situ And Ex-Situ Conservation Methods NEET Biology

List of Some Endangered Plants: The following is a list of some common plants which are reported as endangered, appearing in various books. The list is divided into four groups for the sake of easy information.

1. Endangered Ornamental Plants. The following are some well-known plants grown in gardens:
   • Aerides Ctispum; Fam. Orchidaceae: important for its showy flowers.
   • Cymbidium Macrorhizon; Fam. Orchidaceae, terrestrial leafless orchid, rare occurrence, horticultural importance.
   • Peiphiopedilum Fairieanum; Fam. Orchidaceae; Asian Lady’s Slipper; known for its flowers.
   • Rhododendron Edgeworthii; Fam. Ericaceae; epiphytic ornamental herb of horticultural value.
   • Symploca Chengapae; Fam. Symplocaceae; ornamental tree with fragrant flowers.
2. Endangered Plants Of Medicinal Value. Some of the medicinal plants falling in this category are given below.
   • Atropa Acuminata; Fam. Solanaceae; Sag angur, Angur shefa; this herb is called Indian Belladonna.
   • Commiphora Wightii; Fam. Burseraceae; Guggul; this small tree is a source of oleoresin which among other things is known to reduce cholesterol levels in the blood.
   • Coptis Teeta; Fam. Ranunculaceae; Mishme teeth; herb useful for medicine obtained from rhizomes.
   • Podophyllum Hexandmm; Fam. Podophyllaceae; Papri, Ban-baingan; a drug from rhizomes, besides being stimulant and purgative, has destructive action on cancerous tissues.
   • Ravolfia Serpentina; Fam. Apocynaceae; sarpgandha; air dried roots are useful as antihypertensives and sedatives.
   • Saussurea Lappa; Fam. Asteraceae (Compositae); Kuth, Brahmakamal; roots are used in the treatment of bronchial asthma.
3. Endangered Plants Of Scientific Value. These plants are either botanical curiosities or academically important.
   • Balanophora Involucrata; Fam. Balanophoraceae; fleshy tuberous root parasite of trees.
   • Dischidia Bengalensis; Fam. Asclepiadaceae; leaves form pitchers, and special branched roots develop from the petiole for absorption.
   • Nepenthes Khasiana; Fam. Nepenthaceae; insectivorous pitcher plant.
   • Psilotum Nudum; Fam. Psilotaceae (Pteridophytes); a primitive leafless pteridophyte of academic interest.
   • Sapria Himalayana; Fam. Rafflesiaceae; root parasite with flowers up to 35 cm in diameter, root parasite.
   • Tetracentron Sinense; Fam. Tetracentraceae; a primitive vessels dicotyledonous plant of great academic interest.
4. Endangered Plants Of Economic Importance. Some of the economically useful plants which come under the category of threatened plants are given below.
   • Dioscorea Spp.; Fam. Dioscoreacea; this is known as a source of steroidal hormones.
   • Phyllostachys Bambusoides; Fam. Gramineae (Poaceae); bamboo of great economic value; such as wickerwork, walking sticks, manufacture of writing and printing papers.
   • Pinus Gerardiana; Fam. Pinaceae (Gymnosperms); chilgoza; the seeds called chilgoza are edible.
   • Santalum Album; Fam. Santalaceae; Chandan; useful in perfumery.

NEET Biology Biodiversity and Wildlife Conservation Various Protected Wild Animals In India

1. Reptiles
   1. All species of Monitor Lizard
   2. Water Lizards
   3. Gavialis
   4. Python
   5. Leathery tortoise.
2. Birds
   1. Bustard
   2. Pink-headed ducks
   3. Pheasants
   4. White-eyed ducks.
3. Mammals
   1. Indian Rhinoceros
   2. Lion
   3. Tiger
   4. White tiger
   5. Panther
   6. Snow Leopard
   7. Clouded Leopard
   8. Gazelle
   9. Kashmir Stag
   10. Swamp deer
   11. Musk deer
   12. Lasser Panda
   13. Pangolin
   14. Wild ass
   15. Gibbons
   16. Lion-tailed monkeys
   17. Golden langurs
   18. Nilgiri Langur
   19. Malabar Langur
   20. Lakhi-mpur Langur
   21. Travancore Langur.

In-Situ And Ex-Situ Conservation Methods NEET Biology

Some Endangered Animal Species In India

1. Reptiles
   1. Reticulated Python — Python reticulatus.
   2. Indian Rock Python — Python molurus.
   3. Water Monitor — Varanus salvator.
   4. Common Indian Monitor — Varanus bengalensis.
   5. Tortoise Shell Turtle — Eretmochelys imbricata.
   6. Gavialis
2. Birds
   1. Black-Necked Crane — Grus nigricollis.
   2. Cheer Pheasant — Catreus wallichii.
   3. Himalayan Monal Pheasant — Lophophorus impedance.
   4. Western Tragopan — Tragopan melanocephalus.
   5. Likh Florican — Sypheotides indica.
   6. Great Pied Hornbill — Buceros bicornis.
   7. Great Indian Bustard — Ardeotis nigriceps.
   8. Jerdon’s Courser — Cursorius bitorquatus.
   9. Nilgiri Tahr — Hemitragus hylocrius
   10. White-eyed duck.
3. Mammals
   1. Mouse Deer — Trigulus memmina.
   2. Hangul/Kashmir Stag — Cervus eephus hung.
   3. Thamin/Brow Antlered stag — Cennts eldi eldi.
   4. Four Horned Antelope — Tetracerus quadricornis.
   5. Wild Buffalo — Bubalus bubalus.
   6. Asiatic Wild Ass — Asians hemionus khur.
   7. One Horned Rhino — Rhinoceros unicornis.
   8. Asian Elephant— Eleplias indicus ( = E. maximum).
   9. Red Panda — Ailurus fulgens.
   10. Sloth Bear — Melurus ursinus.
   11. Himalayan Brown Bear — Ursus arctos isabellinus.
   12. Indian Wild Dog — Cam’s alpinus.
   13. Wolf — Canis lupus.
   14. Fishing Cat — Felis viverrina.
   15. Golden Cat — Felis temminki.
   16. Snow Leopard — Panthera uncia.
   17. Clouded Leopard — Neofelis nebulosa
   18. Hoolock Gibbon — Hylobates hoolock.
   19. Nilgiri Langur — Presbytis johni.
   20. Lakhimpur Langur
   21. Tanvancore Langur
   22. Long-Tailed Macaque — Macaco silenus.
   23. Gibbons

NEET Biology Biodiversity and Wildlife Conservation Various Laws For Conservation Of Forest And Wild Life

Forest And Wildlife Laws. Several legal provisions exist in our country to safeguard the national interests related to forests and wildlife. Notable amongst them are listed below:

Forest Act 1927. This act aims to consolidate the law relating to forests, and its basic objectives are:

1. Setting up and managing reserved forests, protected forests and village forests ;
2. Protection of non-government forests and forest land ;
3. Control of movement of forest produce ;
4. Control of cattle grazing.

Wildlife (Protection) Act 1972, (Amended 1991). This act provides for the protection of wild animals, birds and plants, and includes the following objectives:

1. Restriction and prohibition on hunting of animals;
2. Protection of specified plants;
3. Setting up and managing sanctuaries and national parks
4. Empowering zoo authority with control of zoos and captive breeding
5. Control of trade and commerce in wildlife, wildlife products and trophies.

National Forest Policy (1988). The principal aim of our Forest Policy is to ensure environmental stability and maintenance of ecological balance including atmospheric equilibrium which are vital for all life forms, human, animal and plant. The derivation of direct economic benefit (for example production of wood and other materials) is considered subordinate to the principal aim.

NEET Biology Biodiversity and Wildlife Conservation Synopsis

Inexhaustible Resources. These are present in plenty and cannot be exhausted by man’s consumption viz. air, sand, clay etc. Although air will never become limited, its quality can be affected due to the continuous increase in human population.

• Exhaustible Resources can be exhausted by man’s consumption.
• Renewable Resources are those which are being continuously consumed by man but renewed by nature, for example, water, wood, natural pastures, soil living organisms etc. The resources reappear by quick replacement, recycling and reproduction in a particular time.
• Non-renewable resources. They are not renewable after use and are not replenished by nature, for example, fossil fuel, metallic ores viz. copper, iron etc. Fossil fuels include coal, petroleum etc.
• Extensive Plantation of trees is called afforestation.
• The agro-forestry includes a variety of land uses when woody species are grown in combination with herbaceous crops.
• Most biotic resources are renewable
• Deforestation causes extinction of plant, animal and microbial species.
• Grassland with scattered trees is called rangeland
• Wetlands may be either freshwater or saltwater.
• Biomass energy is biomass
• Agar is obtained from marine red algae
• Mine soil can be restored by revegetation

Indian Forests. In India, the forests cover an area of about 8 lakh square km. There are about 15000 species of flowering plants and almost 3000 species of non-flowering plants are present. From the forests, timber, fuel wood, bamboo, medicines, fibres, gum, resins, rubber, aromatic oil, colours, oil, seeds and a number of other small products are obtained, without which our daily life cannot be imagined.

Biodiversity And Wildlife Conservation NEET Notes

India’s Main Forest Areas Are the Himalayan area, valley area, Ganges—Sindhu plains, Rajasthan, Sundarban and eastern and western ghats, south India Andaman Nicobar and Lakshadweep and eastern India.

Forest Cover In India (1999 Estimate)

Differences Between Fresh Water Wetland And Marine Wetland. Freshwater wetlands including marshes, swamps and riverine are highly productive. Marine wetlands include highly productive estuaries and provide food and habitat to marine animals. Mangroves are the dominant plant species.

Differences Between Wetland And Grassland. Wetlands are low-lying areas usually covered by shallow water and have water-tolerant vegetation whereas grassland provides foliage and habitat to domestic animals and wildlife.

Differences Between Deforestation And Desertification. The cutting of forest is termed deforestation and conversion of grassland or forest into desert is desertification.

NEET Biology Biodiversity and Wildlife Conservation Ozone Layer

Ozone occurs in minute traces in the atmosphere. It has a peak concentration of around 25 km above the surface of the earth.

• At no level, the ozone’s concentration is more than a millionth of the main atmosphere.
• If the entire ozone content is compressed at normal pressure and temperature, it will constitute a layer of only 3 mm thick.
• Ozone has played a vital role in the evolution of life. Ozone plays a life-sustaining role by not allowing harmful radiation to reach the earth.
• 12 Mega diversity countries — India is one

Patterns Of Biodiversity

1. Latitudinal gradients.
2. Species area – relationship.

Alexander Von Humboldt = log S = log C + Z log A

Importance Of Species Diversity To Ecosystem

• Stability
• Production
• Ecosystem Health

Loss Of Biodiversity

• Extinct
• Extinct in wild
• Critically endangered
• Vulnerable
• Low risk
• Data Deficient
• Not evaluated.

Causes Of Loss Of Biodiversity

1. Habitat loss and fragmentation.
2. Overexploitation.
3. Alien species invasions.
4. Co-extinctions

Conservation Of Biodiversity

• In-situ Conservation
  1. Hospoli
  2. Protected area,
  3. Sacred grooves
  4. Sacred forests.
  5. Gene banks and Seed banks
• Ex-Situ Conservation
  1. National Parks
  2. Sanctuaries
  3. Biosphere reserves

Biodiversity And Wildlife Conservation NEET Notes

Need For Conservation Of Biodiversity Species

1. Narrow utilitarian
2. Broadly utilitarian
3. Ethical arguments

NEET Biology Biodiversity and Wildlife Conservation Questions From Competitive Examinations

Question 1. Number of Endangered Species of Angiosperms in India:

1. 487
2. 15, 000
3. 5000
4. 3000.

Answer: 4. 3000

Question 2. World Wildlife Fund was organised by UNESCO in:

1. 1961
2. 1983
3. 1931
4. 1915.

Answer: 1. 1961

Question 3. Todaba National Park is located in

1. Mumbai
2. Cochin
3. Chennai
4. Chandrapura

Answer: 4. Chandrapura

Question 4. The species of animal protected in Biligiri Rangaswamy National Park is:

1. Panther
2. Different species of birds
3. Tiger
4. Elephant.

Answer: 4. Elephant.

Question 5. The most threatening factor for the survival of plant biodiversity is:

1. Destruction of natural habitat
2. Biosphere reserve
3. Vulnerable ecosystems like mangroves and wetlands
4. Inaccesibility of habitat.

Answer: 1. Destruction of natural habitat

Question 6. In bioreserves is allowed.

1. Restricted human population
2. Private operations
3. No human population
4. Permanent human population.

Answer: 1. Restricted human population

Biodiversity And Wildlife Conservation NEET Notes

Question 7. Which endangered animal is the source of the world’s finest, lightest, warmest and most expensive wool-the shahtoosh?

1. Chiru
2. Nilgai
3. Cheetal
4. Kashmiri goat.

Answer: 1. Chiru

Question 8. According to Indian Forest policy what percentage of land area should be under forest cover?

1. 13 per cent
2. 23 per cent
3. 33 per cent
4. 43 per cent.

Answer: 3. 33 per cent

Question 9. Species listed in the “Red Data Book” are:

1. Endangered
2. Threatened
3. Vulnerable
4. All the above.

Answer: 4. All the above.

Question 10. Similipal is:

1. Sanctuary
2. National Park only
3. Biosphere Reserve
4. ZOO.

Answer: 3. Biosphere Reserve

Question 11. Which is the most effective way to conserve the plant diversity of an area?

1. By creating biosphere reserve
2. By creating botanical gardens
3. By developing a seed bank
4. By tissue culture method.

Answer: 1. By creating biosphere reserve

Question 12. Which one of the following is a pair of endangered species?

1. Garden lizard and Maxican poppy
2. Rhesus monkey and Sal tree
3. Indian peacock and Carrot grass
4. Hornbill and Indian Aconite.

Answer: 4. Hornbill and Indian Aconite.

Question 13. If the Bengal tiger becomes extinct:

1. Hyaenas and Wolves will become scarce
2. The wild areas will be safe for man and domestic animals
3. Its gene pool will be lost forever
4. The population of beautiful animals like deer will get stabilized.

Answer: 3. Its gene pool will be lost forever

Question 14. Which of the following animals is protected in Kaziranga Sanctuary of Assam?

1. Indian bison
2. Indian lion
3. Indian rhinoceros
4. Indian elephant.

Answer: 3. Indian rhinoceros

Biodiversity And Wildlife Conservation NEET Notes

Question 15. According to IUCN Red List, what is the status of Red Panda (Ailurus fulgens)?

1. Vulnerable species
2. Critically endangered species
3. Extinct species
4. Endangered species.

Answer: 4. Endangered species

Question 16. Biodiversity Act of India was passed by the Parliament in the year:

1. 1996
2. 1992
3. 2002
4. 2000.

Answer: 3. 2002

Question 17. One of the ex-situ conservation methods for endangered species is:

1. Wildlife sanctuaries
2. Biosphere reserves
3. Cryopreservation
4. National parks.

Answer: 3. Cryopreservation

Question 18. Genetic diversity in agricultural crops is threatened by:

1. Introduction of high-yielding varieties
2. Intensive use of fertilizers
3. Extensive intercropping
4. Intensive use of biopesticides.

Answer: 1. Introduction of high-yielding varieties

Question 19. Blackbuck (Autilope cervical) is an example of:

1. Endangered species
2. Extinct species
3. Vulnerable species
4. Conservation-dependent species.

Answer: 3. Vulnerable species

Question 20. Keystone species deserve protection because these

1. Are capable of surviving in harsh environmental conditions
2. Indicate the presence of certain minerals in the soil
3. Have become rare due to overexploitation
4. Play an important role in supporting other species.

Answer: 1. Are capable of surviving in harsh environmental conditions

Question 21. In India, we find mangoes with different flavours, colours, fibre content, sugar content and even shelf-life. The large variation is on account of:

1. Species diversity
2. Induced mutations
3. Genetic diversity
4. Hybridization.

Answer: 3. Genetic diversity

Question 22. Biosphere Reverses differ from national parks and wildlife sanctuaries because in the former:

1. Human beings are not allowed to enter
2. People are an integral part of the system
3. Plants are paid greater attention than the animals
4. Living organisms are brought from all over the world and preserved for posterity.

Answer: 2. People are an integral part of the system

Question 23. Which one of the following is the correctly matched pair of an endangered animal and a National Park?

1. Great Indian Bustard — Keoladeo National Park,
2. Wild ass — Dudhvva National Park
3. Lion — Corbett National Park
4. Rhinoceros — Kaziranga National Park.

Answer: 3. Lion — Corbett National Park

Question 24. Which of the following is considered a “hot spot” of biodiversity in India?

1. Eastern Ghats
2. Aravalli Hills
3. Western Ghats
4. Indo-Gangetic plain.

Answer: 3. Western Ghats

Question 25. Which one of the following is not included under in-situ conservation?

1. Biosphere reserve
2. National Park
3. Sanctuary
4. Botanical garden.

Answer: 4. Botanical garden

Types Of Biodiversity NEET Biology

Question 26. Which of the following parts of an animal and a plant represents endangered organisms in India?

1. Cinchona and Leopard
2. Banjan and Black buck
3. Bentinckia nicobarica and Red Panda
4. Tamarind and Rhesus monkey.

Answer: 3. Bentinckia nicobarica and Red Panda

Question 27. Which one is a critically endangered animal species?

1. Antelope cervicapra
2. Sus salvanius
3. Ailttnts fulgens
4. Caloles versicolor
5. Hyla.

Answer: 2. Sus salvanius

Question 28. Which of the following regions of our country are known for their rich biodiversity?

1. Western ghats and eastern Himalayas
2. Western ghats and Deccan plateau
3. Eastern Himalayas and gangetic plane
4. Trans Himalayas and the Deccan peninsula.

Answer: 1. Western Ghats and the eastern Himalayas

Question 29. Pure clay is not suitable for plant growth because:

1. It is chemically inert
2. It is chemically active
3. It forms a solid non-penetrable mass
4. All of the above reasons.

Answer: 3. It forms a solid non-penetrable mass

Question 30. Humus is an example of:

1. Soil structure
2. Crystalloids
3. Organic colloids
4. None of them.

Answer: 3. Organic colloids

Question 31. Restoration of ecological equilibrium in mined areas can be achieved through:

1. Prevention of grazing
2. Prevention of soil erosion
3. Revegetation of the mined habitats
4. Conversion of mined habitats into agricultural ecosystems.

Answer: 3. Revegetation of the mined habitats

Question 32. In the Northern Indian plains, there is an increase in floods in recent times due to:

1. Soil erosion in the plains
2. Soil conservation on the hills
3. Deforestation in the plains
4. Deforestation in the catchment area.

Answer: 4. Deforestation in the catchment area.

Question 33. Laterization is a process that results in the:

1. Degradation of soil
2. Purification of water
3. Formation of soil
4. Sterilization of soil.

Answer: 3. Formation of soil

Question 34. Which of the following soils cracks and shrinks most as it dries:

1. Porous soil
2. Clay soil
3. Loam soil
4. Sandy soil.

Answer: 2. Clay soil

Question 35. What is the best pH of the soil for the cultivation of plants:

1. 3.4 = 5.4
2. 6.5 = 7.5
3. 4.5 = 8.5
4. 5.5 = 6.

Answer: 4. 5.5 = 6.

Types Of Biodiversity NEET Biology

Question 36. Deforestation causes:

1. Soil erosion
2. Soil pollution
3. Water pollution
4. Noise pollution.

Answer: 1. Soil erosion

Question 37. Which are the dense forests?

1. Tropical evergreen forests
2. Tropical deciduous forests
3. Tropical Savannah
4. Chaparral.

Answer: 1. Tropical evergreen forests

Question 38. Which of the following is the main reason for the extinction of animals?

1. Predation
2. Pollution
3. Destruction of habitat
4. Felling of trees.

Answer: 3. Destruction of habitat

Question 39. Rhizophora occurs in

1. Mangrove
2. Tropical rain forests
3. Tropical deciduous forests
4. Both (2) and (3)

Answer: 1. Mangrove

Question 40. The major fuel component of biogas is:

1. CO
2. CH₄
3. CH₃
4. CO₂

Answer: 2. CH₄

Question 41. Water infiltration will be slowest in:

1. Black cotton soil
2. Sandy soil
3. Loam soil
4. Red soil.

Answer: 1. Black cotton soil

Question 42. The amount of alcohol allowed to be mixed with petrol in India is:

1. 10-15%
2. 10%
3. 5%
4. 2.5%.

Answer: 3. 5%

Question 43. More than 70% of world’s freshwater is contained in:

1. Antarctica
2. Glaciers and Mountains
3. Greenland
4. Polar ice.

Answer: 4. Polar ice.

Question 44. Identify the odd combination of the habitat and the particular animal concerned:

1. Sunderbans – Bengal Tiger
2. Periyar – Elephant
3. Rann on Kutch – Wild Ass
4. Dachigam National Park – Snow Leopard

Answer: 2. Periyar – Elephant

Question 45. One of the endangered species of Indian medicinal plants is of:

1. Ocimum
2. Garlic
3. Nepenthes
4. Podophyllum

Answer: 4. Podophyllum

Question 46. In your opinion, which is the most effective way to conserve the plant diversity of an area?

1. By developing a seed bank
2. By tissue culture method
3. By creating biosphere reserve
4. By creating a botanical garden.

Answer: 3. By creating biosphere reserve

Question 47. Which of the following represents the maximum number of species among global biodiversity?

1. Lichens
2. Fungi
3. Mosses and Fems
4. Algae

Answer: 2. Fungi

Question 48. Manas Sanctuary is located at:

1. Assam
2. Bihar
3. Gujarat
4. Rajasthan.

Answer: 1. Assam

Question 49. Assertion (A): Tropical rainforests are disappearing fast in developing countries such as India.

Reason (R): No value is attached to these forests because they are poor in biodiversity.

1. Both (A) and (R) are true and (R) is the correct explanation of the (A)
2. Both (A) and (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is a true statement but (R) is false
4. Both (A) and (R) are false.

Answer: 3. (A) is a true statement but (R) is false

Question 50. Habitat loss and fragmentation, over-exploitation, alien species invasion and co-extinction are causes of:

1. Population explosion
2. Migration
3. Biodiversity loss
4. Pollution
5. Ecological succession.

Answer: 3. Biodiversity loss

Question 51. The venue and year of the Earth Summit on Conservation of Biodiversity was:

1. South Africa, 2002
2. Rio de Janeiro, 1992
3. Johannesburg, 2004
4. Stockholm, 1974
5. Ramsar, 1974.

Answer: 2. Rio de Janeiro, 1992

Question 52. India became a party to the ‘Convention on Biological Diversity’ in the year.

1. 1994
2. 1993
3. 1992
4. 1983.

Answer: 1. 1994

Question 53. Which one of the following is not observed in biodiversity hotspots?

1. Endemism
2. Species richness
3. Accelerated species loss
4. Lesser inter-specific competition.

Answer: 4. Lesser inter-specific competition.

Threats To Biodiversity NEET Exam Preparation

Question 54. World Summit on Sustainable Development (2002) was held in:

1. Brazil
2. Sweden
3. Argentina
4. South Africa.

Answer: 4. South Africa.

Question 55. Which one of the following has the highest number of species in nature?

1. Fungi
2. Insects
3. Birds
4. Angiosperms.

Answer: 2. Insects

Question 56. Which one of the following shows the maximum genetic diversity in India?

1. Groundnut
2. Rice
3. Maize
4. Mango.

Answer: 2. Rice

Question 57. Which one of the following expanded forms of the following acronyms is correct?

1. IPCC = International Panel for Climate Change
2. UNEP = United Nations Environmental Policy
3. EPA = Environmental Pollution Agency
4. IUCN = International Union for Conservation of Nature and Natural Resources.

Answer: 4. IUCN = International Union for Conservation of Nature and Natural Resources.

Question 58. World Biodiversity Day is observed on:

1. 3rd October
2. 5th June
3. 29th December
4. 22th May.

Answer: 4. 22th May.

Question 59. The highest number of species in the world is represented by:

1. Mosses
2. Algae
3. Lichens
4. Fungi.

Answer: 4. Fungi.

Question 60. The relation between species richness and area is described on a logarithmic scale by the equation [where S = species richness, A = area, Z = slope of the line (regression coefficient), C = Y-intercept]

1. log S = log C – Z log A
2. log S = Z log A
3. log S = log C + Z log A
4. log S = log C
5. log C = log S + Z log A.

Answer: 3. log S = log C

Question 61. Which one of the following is not used for ex situ plant conservation?

1. Seed banks
2. Shifting cultivation
3. Botanical Gardens
4. Field gene banks.

Answer: 2. Shifting cultivation

NEET Biology Environmental Pollution And Global Environmental Issues

Environment: The environment includes air, water and land, it also includes buildings, landscapes, oceans, parks, open spaces, vehicles and noise.

Pollution: Environmental pollution is an unfavourable alteration of our surroundings, largely as a by-product of man’s actions through direct or indirect effects of changes in energy patterns, radiation levels, chemical and physical conditions and abundance of organisms.”

• Pollutants can be natural or nian-nuclei. The agents causing pollution are termed pollutants.
• Pollutants. A pollutant is a substance which may alter environmental constituents or cause pollution. Pollutant is also defined as a constituent in the wrong amount at the wrong place at the wrong time. A pollutant may be a chemical substance, pollen, spores, fungus or other similar substances that may change the natural composition of water, air and soil.

NEET Biology Environmental Issues Air Pollution

Harmful substances are added to the atmosphere by man and atmospheric sources. About 10 x 10¹² tonnes of pollutants are added annually to the atmosphere out of which 5 x 10⁸ tonnes (0.05%) is added by activities of man.

Ambient Air. The air we breathe is termed ambient air

Read and Learn More NEET Biology Notes

Normal Composition Of Clean Air

• Nitrogen: 78.08%
• Oxygen: 20.94%
• Argon: 0.93%
• Carbon dioxide: 0.03%
• Methane: 0.0002%
• Hydrogen: 0.0005%
• Other gases: Traces

Pollutants are classified into gaseous and particulate.

Environmental Issues NEET Notes

Sources Of Air Pollution

• Gaseous Pollutants Of Air include CO, CO₂, NO, NO₂, SO₂, Hydrocarbons, fluorides and photochemical oxidants such as peroxyacyl nitrate (PAN), Ozone (O₃) and aldehydes. They mostly come from motor vehicles and industries. PAN is highly toxic and formed in the air by interaction between nitrogen oxides and hydrocarbons in the presence of sunlight.
• Particulate Pollutants. They also come from industries and automobiles. They include fly ash, soot, metal dust, cotton fibres, asbestos fibres, leads, aerosols Ichlorofluoro-carbon (CFCs), Polychlorinated biphenyls (PSBs), Tobacco smoke, smog, pollen, cysts and bacteria,
• Suspended Particulate Matter (SPM). The solid particles or liquid droplets (aerosols) remain suspended in the air. For example, smoke, soot dust, asbestos etc. SPM above the size of 10 mm is trapped by nasal hair, pharyngeal, tracheal and bronchial mucus. The same are coughed out or deposited in the nose as nasal scales.
• Smaller particles of SPM reach the alveoli. There they may be attacked by phagocytes or pass into living cells. SPM causes irritation in the respiratory tract, bronchitis and lung diseases. These particles may cause asbestosis and pneumoconiosis. They also result in reduced visibility.

Aerosols. These are the chemical substances released into the air with force in the form of vapours from jet aeroplanes.

Source Of Aerosols. Fluorocarbons are released from jet propellants.

• Harmful Effect. These fluorocarbons depict the ozone layer of the stratosphere, thus permitting some harmful ultraviolet radiation to reach Earth and damage the life on this planet. Carbon tetrachloride (CC14) which originates from human activity also damages the atmosphere.
• Agricultural Activities As Source Of Air Pollution: Large amounts of pesticides are used in agriculture. When these are sprayed they pollute the air and cause various types of respiratory disorders.
• Use Of Solvents As a Source Of Air Pollution: The available spray paints and furniture polish nowadays contain various types of volatile organic solvents. The small molecules of these solvents mix with the air and pollute it.
• Atomic Energy As a Source Of Air Pollution: The production of atomic energy requires the use of unstable chemical compounds. As soon as they are produced they begin to disintegrate. As a result, harmful radioactive gamma rays are given out. These rays are harmful to all living organisms.

Radioactive Substances are released by nuclear explosions and war explosives.

Stationary Combustion Sources Of Air Pollution:

The majority of gaseous and particulate air pollution result from human fuel combustion. Coal primarily consists of carbon, along with incombustible sulfur and nitrogen. Petroleum primarily comprises hydrocarbons, sulfur, and nitrogen.

• Upon combustion, fossil fuels generate a variety of oxides with carbon dioxide and water. Coal generates mineral ash, a portion of which is released as fly ash.
• Mobile combustion sources encompass locomotives, automobiles, aircraft, and similar vehicles. The primary contaminants from these sources are carbon monoxide (77.2%), nitrogen (7.7%), and hydrocarbons (13.7%).
• The combustion of petroleum in automobiles containing lead compounds such as tetraethyl lead—Pb(C2H5)4 and tetramethyl lead—Pb(CH3)4, releases different particulate lead compounds. Inhaled lead may impede hemoglobin synthesis.

Control of Air Pollution Emissions:

Air pollution at the source is controlled in two ways

1. By separating the pollutants from the harmless gases, and
2. By converting the pollutants to innocuous products before they are released in the atmosphere.

Environmental Issues NEET Notes

Control Of Pollution From Automobile Exhaust

1. Efficient engines can reduce the unburnt hydrocarbons in auto emissions.
2. The use of catalytic converter filler in the vehicle can convert NO₂ to nitrogen reducing the hazards of NO₂
3. Use of good quality of fuel.
4. Unleaded petrol can reduce the load of lead in the exhaust.
5. The use of CNG (compressed natural gas) lowers the toxic contaminants in the exhaust.

Conversion Of Pollutants. The most important method of conversion of pollutants is oxidation in air.

Common types of Electrostatic precipitators for control of Air Pollution Emissions are Cyclone collectors. Plate-type precipitator and Tube-type precipitator and Lottrell precipitator.

NEET Biology Environmental Issues Global Warming

This refers to the change in the average surface temperature of the globe due to the increasing concentration of greenhouse gases in the atmosphere. Carbon dioxide is the main greenhouse gas. Emissions from the burning of fossil fuels are said to be the main cause of the increase in atmospheric carbon dioxide.

It is estimated that at the present rate of emissions, the global average temperature could rise up to about 4 degrees Celsius in the next 100 years. This will change weather patterns around the globe in turn will have consequences like an increase in sea levels, droughts, desertification, and melting of the glaciers and polar ice sheets.

Climate change will cause serious disruptions in society and may trigger uncertain socio-economic changes. Global warming is considered to be the most important of global environmental concerns and is part of the problem of climate change which is affecting our planet.

Effects Of Global Warming

1. Effect On Weather And Climate,
   • The average temperature of the earth may increase by 1-4° to 5-8°C by the year 2100.
   • Winter precipitation may decrease at lower altitudes.
   • The frequency of droughts and floods may increase.
   • Climatic change is a threat to human health in tropical and subtropical countries.
2. Sea Level Change. Sea levels had been raised by 1 to 2 mm per year during the 20th century. It is predicted that by the year 2100, the global mean sea level can increase up to 0.88 m over the 1990 level. Global warming may contribute to sea level rise due to the thermal expansion of the ocean.
3. Effect On Range Of Species Distribution. Vegetation may extend 250-600 km poleward with a global rise in temperature by 2 to 5°C during the 21st century.
4. Effect On Food Production. Increased temperature will cause an eruption of plant diseases and pests and the vast growth of weeds.

Strategies To Deal With Global Warming: Some of the strategies that could reduce global warming by stabilizing atmospheric concentrations of greenhouse gases include

1. Reducing greenhouse gas emissions by limiting the use of fossil fuels, and by developing alternative renewable sources of energy (for example, wind energy, solar energy, etc.)
2. Increasing the vegetation cover, particularly the forests, for photosynthetic utilization of CO₂
3. Minimizing the use of nitrogen fertilizers in agriculture to reduce NO₂ emissions.
4. Developing substitutes for chlorofluorocarbons.
5. Apart from the above, litigation strategies, and adaptations to address the localized impacts of climate change will be necessary.

CO₂ Fertilization Effect. With a doubling of the atmospheric CO₂ concentration, the growth of many plants, particularly the C₃ species, under favourable conditions of water, nutrients, light and temperature, could increase by about 30%, on average, in the short-term (i.e. up to a few years).

• The response of plants to elevated concentrations of CO₂ is known as the Carbon dioxide fertilization effect. Due to increased CO₂ concentration, the rate of photosynthesis will increase and the stomatal conductance will decrease (due to partial closure of stomata).
• Thus, the transpiration rate may be reduced and consequently, water-use efficiency will increase.

Greenhouse Effect. Greenhouse gases (CO₂ CH₄ CFC and NO₂) allow sun rays of wavelength 0.15 to 4mm on earth but absorb infrared rays emitted from the earth’s surface. This causes an increase in the temperature of the earth. If the temperature of the earth keeps on increasing at this rate, it will cause the melting of ice on the poles which will result in the submerging of many parts of the earth.

Environmental Issues NEET Notes

Main Greenhouse Gases

NEET Biology Environmental Issues Ozone Shield

Chlorine from chlorofluorocarbons (CFCs) and bromine from halogens (C_x F_xBr_x) react with ozone in the presence of UV radiations and destroy the same.

• One molecule of Cl/Br destroys about 100,000 molecules of ozone.
• There is a hole in the ozone shield over Antarctica and less one over the North Pole. 60% of ozone is destroyed over the South Pole in spring.
• Thinning of the ozone shield will allow shorter UV radiations to reach Earth and cause extensive damage including skin cancer.

NEET Biology Environmental Issues Ozone Layer Depletion

The upper part of the atmosphere—15-20 km above the Earth- supports a thin layer of ozone gas which filters out the harmful ultraviolet radiation coming from the Sun. If all the ozone is collected in a thin layer around the globe, its thickness would be just about -01 mm. _x

Scientific investigations going back to several decades have revealed that this life-saving blanket of ozone is thinning out thereby putting life on Earth at risk. Every year, during winter and spring months, the level of ozone concentration over the Antarctic falls dangerously letting ultraviolet rays come in quantities which can damage human health.

• For instance, the increased level of ultraviolet rays can cause skin cancer and eye cataracts. The depletion of the ozone layer takes place due to a reaction between ozone and chlorofluoro¬carbons (CFCs), which are released from aerosol spray cans, polyurethane foams, air conditioners and refrigerators.
• One molecule of chlorofluorocarbon can damage 100,000 molecules of ozone. Already so much ozone has been damaged that even if all the production of the CFCs is halted forthwith, it may take several decades for ozone to recover to its normal levels.
• The size of the ozone hole over Antarctica has been increasing every year. In 1979 the ozone hole area was 0.7 million km². It increased to 27.2 million km² in 1998. This is twice the size of Antarctica.

An equilibrium is established between generation and destruction of 03, leading to a steady state concentration of the ozone layer in the stratosphere between 20 and 26 km above the sea level.

• The thickness of the vertical column of the stratospheric O₃ layer, condensed to standard temperature and pressure, averages 0.29 cm above the equator and may exceed 040 cm above the poles at the end of the winter season. This layer acts as the ozone shield protecting the earth’s biota from the harmful effects of strong UV radiation.
• CFCs produce active Chlorine (Cl with Cl radical) in the presence of UV radiations. These radicals catalytically destroy ozone converting it into oxygen. CH₄ and N₂O also cause ozone destruction.

Ozone Layer As Protective Layer: The ozone layer in the stratosphere is very useful to human beings because it absorbs the major part of harmful ultraviolet radiation coming from the sun. Therefore, it is called a protective layer. However, it has been observed that the ozone layer is getting depleted.

• One of the reasons for the depletion of the ozone layer is the action of aerosol spray propellants. These are the chemicals such as fluorocarbons and chlorofluorocarbons, These compounds react with ozone gas in the atmosphere thereby depleting it.
• Scientists all over the world are worried about the destruction of the ozone layer. If the ozone layer in the atmosphere is significantly decreased, these harmful radiations would reach the earth and would cause much damage such as skin cancer, and genetic disorders in men and other living forms.
• Efforts are being made to find substitutes for these chemicals which do not react with ozone.

Ozone Hole: During the period 1956-1970 the springtime O₃ layer thickness above Antarctica varied from 280-325 Dobson units. Thickness was sharply reduced to 225 DU in 1979 and 136 DU in 1985. The decline in springtime ozone layer thickness is called an ozone hole. It was first noted in 1985 over Antarctica.

Cooling of the stratosphere (where the ozoneosphere is located) will produce a bigger ozone hole not only over Antarctica but also over the Arctic region. The ozone layer will further thin out from the rest of the stratosphere. It will be accompanied by major climatic changes all over the globe. Forests will be wiped out in many places. Radio communication will be disrupted.

Air Pollution Causes And Effects NEET Biology

Effect Of Ozone Depiction. CFC, aerosol depletes the ozone layer in the higher atmosphere. Thinning of the ozone layer permits more harmful ultraviolet light to reach the earth. UV rays cause sunburn, blindness and inactivation of proteins, RNA, DNA and plant pigments.

UV-B Radiations inhibit photosynthesis in most of the phytoplanktons as it penetrates through the clear open seawater. CFCs have produced a hole in the ozone layer over Antarctica, This hole widened from 129 to 133 dobsons in just one year (1994).

NEET Biology Environmental Issues Water Pollution

Domestic and industrial wastes are poured into the water. Polluting strength is characterised by its biochemical oxygen demand (BOD). BOD is the amount of O₂ taken by microorganisms present in water. Its normal limit is 3 ppm. However, the discharge of pollutants may raise BOD to 2500 ppm.

Main Pollutants

1. Compounds of mercury, arsenic and lead present in polluted water are poisonous.
2. Some compounds affect water plants.
3. Organic sulphur compounds interfere with nitrification.
4. Inorganic nitrates and phosphates stimulate excessive plant growth in lakes and reservoirs.
5. Some residues left behind such as organochlorides as a result of the use of certain pesticides are highly persistent and pass through food chains. The pesticides result in the destruction of aquatic life.
6. Change in colour is a very common effect. It is produced by the dyes and inorganic substances like chromium and iron compounds present in the discharges.
7. Turbidity due to very fine suspended materials or colloidal substances makes water unfit for drinking and use in industries.
8. An unpleasant odour is resulted due to the presence of free chlorine, phenol, hydrogen sulphide, ammonia, algae and micro-organisms.
9. Soaps, detergents and alkalies form foam.
10. Fluoride contents of water cause fluorosis.
11. Eutrophication is a natural phenomenon observed in deep lakes. Excessive growth of microorganisms consumes much of dissolved O₂ and other aquatic life such as fishes are deprived of O₂ It occurs due to an increase in pollution content, basically, nitrates and phosphates are the main causes.
12. Oil spills from ships.

The Major Sources Of Pollution Of Indian Rivers

Marine Pollution. The world’s oceans and seas are getting increasingly polluted. The urban and rural waste finds its way through rivers into the seas and oceans. Marine pollution takes the form of oil spills, discharge of heavy metals and halogenated organic compounds into the seas.

• Algal blooms, caused by the flow of chemicals from urban effluents release toxic substances into the water and soak all oxygen from it. The result is that marine life including fish is starved of oxygen and in large numbers.
• This phenomenon is called eutrophication. Some of the harmful chemicals, particularly from industrial wastes, end up in the human food chain. Pollution of sea waters has serious health consequences.

Control Of Water Pollution

1. Sewage should be fully treated before pouring into rivers.
2. Water treatment plants should be implemented in all industries.
3. Chemical oxidation of water is done with the help of ozone. It oxidises water and disinfects the water.
4. Pseudomonas putida is a bacterium which breaks down esteric compounds, so it is used for the removal of oil spills.

Treatment Of Domestic Sewage. The municipal wastewaters are treated in Effluent Treatment Plant (ETP) prior to disposal in water bodies. It consists of 3 steps: primary, secondary and tertiary.

1. Primary Treatment It includes physical processing, such as sedimentation, floatation, and shredding (fragmenting and filtering). These processes remove most of the large debris.
2. Secondary Treatment It is a biological method.
   • Activated Sludge Method. Sewage, after primary treatment, is pumped into an aeration stabilization or oxidation pond. Here, it is mixed with air and sludge containing algae and bacteria. Bacteria consume the organic matter.
   • The process results in the release of CO₂ and the formation of sludge or biosolid. Algae produce oxygen for the bacteria. The water, which is now almost clear of organic matter, is chlorinated to kill microorganisms.
3. Tertiary Treatment. It involves the removal of nitrates and phosphates. The water, after the above treatment, is then released. It can be reused.

Air Pollution Causes And Effects NEET Biology

Fluorosis: Excessive ingestion of fluorides over a long period causes fluorosis.

• Industrial fluorosis is said to affect agricultural and horticultural crops.
• Fluorosis results in various neuro-muscular disorders, gastrointestinal problems, allergies, dental disorders and severe skeletal disorders leading to crippling of people.
• In 13 states in India, the drinking water contains high amounts of fluoride.
• The human body can tolerate a maximum level of fluoride of 1.5 parts per million (mg/1 water).

NEET Biology Environmental Issues Soil Pollution

It is a result of human activities, such as the dumping of wastes, the use of agrochemicals mining operations and urbanization. Alteration in soil by addition and removal of materials leading to reduced productivity is called soil pollution. Here, soil productivity includes both the quantity and tire quality of the produce.

Soil Pollutants. Substances which reduce the productivity of the soil are regarded as soil pollutants.

1. Soil pollution may be due to: Soil pollutants which include
   • Pesticides,
   • Fertilisers,
   • Industrial wastes,
   • Salts,
   • Radio-nuclides (W) concrete,
   • Asphalt,
   • Tin, iron, lead, copper, mercury, aluminium and
   • Plastics,
   • Discarded food,
   • Paper and
   • Carcasses.
2. The direct effect of dumping of industrial wastes and use of pesticides.
3. Pollutants washed out of the atmosphere, for example, acid rain. All these pollutants alter the basic structure and fertility of the soil. Microorganisms are killed, which also alter soil composition.
4. Intensive farming with poor drainage is also damaging large areas of land in India.

Control Measures Used For Controlling Soil Pollution: Soil pollution caused by solid wastes can be corrected by the following methods

1. Salvage. Articles which can be recycled should be removed from garbage, for example, metals, glass, plastic, polythene, paper, rags, etc. It involves the collection and categorization of waste.
2. Transfer Stations. They are meant for temporary storage and bulk transport of garbage for safe disposal.
3. Burning. This is a common method for reducing the bulk of waste. Rubbish and garbage are commonly burnt in open spaces. It, however, releases offensive odour and smoke.
4. Incineration. Waste is burnt aerobically at 900-1000°C. The hot gases and smoke are further passed into a chamber where the temperature is 1300°C. It burns the smoke particles.
5. Sewage sludge and industrial wastes are used as bedding material for road construction.
6. Recycling Of Wastes. Paper, glass, polythene and metals can be recycled. Though paper recycling is a bit costlier, it saves a lot of wood. For example, one tonne of recycled paper saves 17 medium-sized trees from felling. Recycling of metals not only saves the scarce resource but is also cheaper and less polluting.

NEET Biology Environmental Issues Noise Pollution

It is a result of modern industrialized urban life. It damages the power of hearing as well as the general health of man. The unit of measurement of sound is Bel (B) commonly used as decibel (dB).

• The most immediate and acute effect of noise pollution is impairment of hearing.
• The physiological effects of sound pollution are an increase in the rate of heartbeats, constriction of blood vessels, digestive spasms, and dilation of the pupil of the eye.
• The normal human hearing range is 50Hz to 15000Hz frequencies.
• Frequencies below 50Hz are called infrasonic (infrasound) and above 15000Hz are ultrasonic (ultrasound).
• Prolonged exposure to noise levels of 80 dB or more leads to loss of hearing ability.

Green Muffler:

Cultivation of vegetation beside roadways to mitigate noise pollution.

NEET Biology Environmental Issues Radioactive Pollution

Sources of environmental radiation are both natural and man-made. The natural sources comprise cosmic rays which reach the surface of the earth from space and terrestrial radiations from radio-nuclides present in the earth’s crust. Many radio-nuclides like radium 224, uranium 235, uranium 238. thorium 232, radon 222, potassium 40 and carbon 14 occur naturally in rocks, soil and water.

• An atomic nucleus as characterised by its atomic number and its neutron number is called a nuclide.
• Each radio-nuclide has a constant decay rate.
• Half-life is the time needed for half of the atoms to decay. This may vary from a fraction of a second to thousands of years.
• Usually, the nuclides with long half-lives are the main sources of environmental concern.
• The human species is the final victim of radioactive pollution as it is at the end of all reactions and interactions.
• Polonium-210. Automobile exhausts have this radioactive carcinogen probably as a companion of antinock lead added to gasoline.
• Radon. A rare radioactive gaseous element is now found to be emitted from several ingredients causing leukaemia, brain tumours and kidney cancers.
• Effects of Radiation Pollution. High doses cause instant death. Low doses cause cancer and mutations which are harmful for the next generations also.

Air Pollution Causes And Effects NEET Biology

Three common dangerous radioactive elements present in nuclear fallout and enter in our bodies:

• Cesium¹³⁷  replaces Na and K in muscles.
• Strontium⁹⁰ replaces calcium in bone and causes bone cancer and leukaemia.
• Iodine¹³¹-overactivates thyroid and damages lymph nodes and bone marrow.

The human species is the only species that actively plays with radioactive materials.

Control Measures: The radio-nuclides are separated by coagulation, and precipitation exchanges and the concentrated or solid radioactive parts are stored or buried.

• The concentrated radioactive parts of wastes are stored in specially insulated tanks.
• Wastes containing materials with half-life cannot be discharged at all.
• Small quantities of the concentrated radioactive part of the wastes can be converted into solids such as concrete, glass or ceramic materials.
• Radioactive wastes are locked in insulated concrete-filled sealed drums and then burst or discharged at least 1000 fathoms deep in the sea.
• Chornobyl (Ukraine, April 1986) Reactor burst due to overheating causing leakage of radioactive substances.

Sources Of Industrial Pollution

Radioactive Pollution Memory Points

• Biotic Index. It is the idea of pollution of a particular water body. Some organisms are used as indicators of water pollution and are classified into the following categories
  • Class 1. Organisms. Caddis fly, Mayfly (pollution intolerant).
  • Class 2. Organisms. Dragonfly, shrimps, Planaria (mild pollution indicators).
  • Class 3. Organisms. Mosquito larva, chironomids, Tubifex (heavy pollution indicators).
• Biotic index = number of class 1 organisms + number of class 2 organisms.
• Any aquatic body with a biotic index of more than 15 is clean, lower than 10 is polluted.
• Algal Genus Index (AGI). The presence of 20 or more genera of algae in a water body is an indication of high organic pollution. The growth of less than 5 genera of algae is an indication of clean water.
• Silent Spring. A novel written by Rachel Carson (1962) mentions the effect of DDT on birds. DDT use has been banned in the U.S.A. since then.
• Grey Snow. Occurred in Norway due to soot from the industrial Ruhr area of Germany.
• Minamata Disease. Named after Minamata Bay in Japan where mercury-rich waste from an industrial complex was dumped.
• Gulf War (1990). Fire from oil wells changed the colour of clouds and rain in north India.
• Water pollution leads to the formation of Heat Islands.

Degradation Of Agricultural Land: Over 87 million hectares of agricultural land in India is prone to degradation by severe erosion.

• To minimise soil erosions, practices like contour farming, creation of shelter belts, revegetation of steep slopes, appropriate cropping patterns, etc., are followed.
• In India, there is an immediate prospect of reclaiming 4 million ha of ravines and gullies, 16.73 million ha of culturable wastelands, 9.82 million ha of current fallows, 2.5 million ha of alkaline soil and 5.5 million ha of coastal sandy area.
• Under the seventh five-year plan, an area of 1.5 million ha has been taken up for reclamation.

Degradation Of Agricultural Land Desertification. Desertification is defined as the degradation of land in arid and semi-arid areas due to a variety of reasons. One-fourth of the planet’s area, about 100 countries and about 1 billion people, are affected by the ever-growing problem of desertification.

• The Causes Of Desertification Are Many: overgrazing, climate change, water shortage, overcultivation of land, unsustainable agricultural practices, etc. Desertification has a direct effect on the livelihood of people.
• Droughts and famines are the immediate consequences of desertification. It also leads to human and animal migrations, and social and Inter-state, conflicts. It is conjectured that in the 21st century, conflicts over water and land will rise sharply.

Degradation Of Agricultural Land Synergism: It is increased toxicity by reactions among primary pollutants. Photochemical smog and London smog (or sulphurous smog) are examples of synergism.

Water Pollution Sources And Control Measures NEET

Degradation Of Agricultural Land Tobacco Smoke. Tobacco smoke contains at least seven polycyclic hydrocarbons and CO radioactive polonium 210. Both are carcinogens.

• An average smoker has the risk of developing and dying from lung cancer ten times more than a non-smoker.
• The risk of lung disease is six times that of heart disease of an average smoker as compared to a non-smoker.
• BOD is measured by placing a sample of water containing a known amount of oxygen for five days at 20°C in the dusk. After five days, the oxygen content is measured. A high Biological Oxygen Demand (BOD) indicates a high level of microbial pollution.

NEET Biology Environmental Issues Synopsis

The Environment Protection Act 1986, The Insecticide Act, 1968, The Water (Prevention and Control of Pollution) Act, 1974, and The Air (Prevention and Control of Pollution) Act 1981 are concerned with the protection of air, water and soil.

• The increased amounts of greenhouse gases in the atmosphere are affecting the global climate and this phenomenon is called global change.
• Greenhouse gases are resulting in global warming.
• Radioactive substances are another source of air.
• water and soil pollution. High doses of radiation are fatal.
• High-intensity sound or noise generated by industrial establishments, defence materials and practices, air travel, automobiles and domestic appliances affect human well-being and communication.

Zone-wise Permissible Ambient Noise Levels

• Major issues of global environmental change are global warming and stratospheric ozone depletion.
• Naturally occurring greenhouse gases like carbon dioxide, methane and N₂O in the atmosphere absorb longwave radiations and help maintain the average temperature of Earth around 15°C.
• The increase in concentrations of greenhouse gases is causing enhanced greenhouse effect, increased global temperature, sea level rise, and change in rainfall patterns etc.
• Stratospheric ozone plays a vital role by protecting living organisms from the harmful effects of ultraviolet radiation.
• Ozone hole refers to the thinning of the stratospheric ozone layer during spring.
• The ozone hole was discovered over Antarctica, but it also occurs over the Arctic region.
• Man-made chemicals like CFCs are the major cause of ozone depletion.

Differences Between Point And Non-Point Sources Of Water Pollution

The largest source of air pollution in big cities is auto-mobiles.

• Some of the harmful trace metals are antimony, arsenic, beryllium, cadmium, germanium, lead, mercury, nickel, selenium, vanadium and yttrium.
• Ozone Day is observed on 16th September.
• The ozone hole is most prominent in Australia.
• Ozone, PAN (Peroxy acyl nitrate), HNO₃, and H₂SO₄ are secondary pollutants. Ozone is one gas that is harmful as well as useful for human beings.
• Lead is released during the burning of petroleum.
• Lead is absorbed by the body and inhibits haemoglobin formation.
• Lead also causes deterioration of the central nervous system.
• In Delhi and Kolkata, pollution is due to automobiles and fire.
• In Mumbai, the main source of pollution is industries. DDT is a chlorinated hydrocarbon and shows biomagnification.
• In India, the concentration of DDT in the fat tissue of people is 18-31 ppm.
• According to the reports of the World Resources Institute (an international research organization), almost four million children die each year due to respiratory infections acquired due to pollution,
• Freon gas (a chlorolluoro compound) used in aerosol sprays and jet propulsion is responsible for the depletion of the ozone layer.
• SO₂ emitted from the Mathura refinery is supposed to damage the marble of the Taj Mahal as it converts CaCO₃ (marble) into unstable calcium sulphate.

Environment Pollution Case Study:

Controlling Vehicular Traffic – Use of CNG

• Euro 2 norms = Bharat 2
• Euro 3 norms from April 1, 2005
• Euro 4 Norms from April 1, 2010

Integrated Wastewater Treatment

• Conventional sedimentation, filtering and chlorine treatment.
• Growing/Algae, Fungi, Bacteria in Marshland
• Remedy for Plastic Waste. Formation of polyblend and use in roads,
• Organic farming – Beekeeping, dairy management, water harvesting, composting and agriculture

People Participation In Conservation Of Forests – Chipko Movement, Joint Forest Management

• CPCP – Central Pollution Control Board
• SPM – Suspended Particulate Matter
• CNG – Compressed Natural Gas
• CFCs- Chlorofluoro Carbon
• B- Bel (Unit of Sound)
• dB- Decibel
• BOD- Biological Oxygen Demand
• DO- Dissolved Oxygen
• FOAM- Friends of the Areata Marsh
• ppm- parts per million
• ppb- parts per billion
• e-waste- electronic waste
• DB- Dobson unit
• ODS- Ozone-depleting substance

Water Pollution Sources And Control Measures NEET

Smog – Smoke + Fog classical smog (London smog) Los Angeles smog (Photo-chemical)

Acid Rains NO₂ + SO₂ + Water

Ozone depletion

Global warming: Temp of the earth has increased by 0. 6°C doing the last century

• Environment (Protection) Act 1986
• Air (Prevention and Control of Pollution) Act 1981 amended in 1983
• Water (Prevention and Control of Pollution) Act 1974.

Green House Gases

• CO₂ = 60%
• Methane = 20%
• CFCs = 14%
• N₂O = 6%

NEET Biology Environmental Issues Questions From Competitive Examinations

Question 1. Depleting of ozone umbrella is due to:

1. CFCs
2. PAN
3. CO₂
4. Coal burning.

Answer: 1. CFCs

Question 2. The American aquatic weed, which had become a trouble in India is?

1. Dolicus
2. Hibiscus
3. Eicchhomia
4. Hispinosa.

Answer: 3. Eicchhomia

Question 3. Which of the following causes the greenhouse effect?

1. Oxygen and hydrogen
2. Carbon dioxide and nitrogen
3. CO₂ and chlorohydrocarbons
4. Nitrogen and sulphur dioxide.

Answer: 3. CO₂ and chlorohydrocarbons

Question 4. NEERI is:

1. National Environmental Engineering Research Institute
2. National Ecological and Environment Research Institute
3. National Eugenics and Ecological Research Institute
4. National Ethological and Ecological Research Institute.

Answer: 1. National Environmental Engineering Research Institute

Question 5. As it passes into the food chain, the concentration of DDT:

1. Remains same
2. Decreases
3. Increases
4. Unpredictable.

Answer: 3. Increases

Question 6. Carbon monoxide kills because it destroys:

1. Haemoglobin
2. Phytochrome
3. Cytochrome
4. Both 1 and 2

Answer: 1. Haemoglobin

Question 7. DDT concentration recorded in the human body has been:

1. 0.3 – 0.7 ppm
2. 1.3 – 3.1 ppm
3. 13 – 13 ppm
4. 30 – 70 ppm.

Answer: 3. 13 – 13 ppm

Question 8. Lead is considered mainly:

1. Soil pollutant
2. Water pollutant
3. Air pollutant
4. Noise pollutant.

Answer: 3. Air pollutant

Water Pollution Sources And Control Measures NEET

Question 9. Which one of the following is not a pollutant?

1. CO₂
2. CO
3. SO₂
4. NO₂

Answer: 1. CO₂

Question 10. A person has an impaired nervous system and signs of madness due to continued intake of metal-contaminated water. The metal is:

1. Lead
2. Calcium
3. Manganese
4. Mercury.

Answer: 1. Lead

Question 11. What is the intensity of sound in normal conversation?

1. 10 – 20 decibels
2. 30 – 60 decibel
3. 70-90 decibel
4. 120- 150 decibels.

Answer: 2. 30 – 60 decibel

Question 12. The reason for lung cancer is:

1. Coal mining
2. Calcium fluoride
3. Cement factory
4. Bauxite mining.

Answer: 3. Cement factory

Question 13. The result of the Ozone hole is:

1. Global Warming
2. Acid rain
3. Greenhouse effect
4. The UV radiations reach the earth.

Answer: 4. The UV radiations reach the earth

Question 14. Ozone hole means:

1. Hole in the stratosphere
2. The same concentration of ozone
3. Decrease in concentration of ozone
4. Increase in the concentration of ozone.

Answer: 3. Decrease in concentration of ozone

Question 15. Ganga Action plan was started in:

1. 1947
2. 1956
3. 1982
4. 1985.

Answer: 4. 1985.

Question 16. Fluoride pollution mainly affects:

1. Kidney
2. Heart
3. Brain
4. Teeth.

Answer: 4. Teeth.

Question 17. E. coli is used as an indicator organism to determine the pollution of water with:

1. Pollen of aquatic plants
2. Heavy metals
3. Faecal matter
4. Industrial effluents.

Answer: 3. Faecal matter

Question 18. BOD is a measure of:

1. Amount of oxygen needed by green plants during the night
2. Industrial wastes poured into water bodies
3. Amount of co inseparably combined with haemoglobin
4. The extent to which water is polluted with organic compounds.

Answer: 4. Extent to which water is polluted with organic compounds.

Question 19. The frequent occurrence of water blooms in a lake indicates which of the following?

1. Deficiency of nutrients
2. Deficiency of oxygen
3. Excessive availability of nutrients
4. Absence of herbivores in the lake.

Answer: 3. Excessive availability of nutrients

Question 20. A range of loudness of sound of 70-90 decibels is rated as:

1. Very loud
2. Painful
3. Quiet
4. Uncomfortable.

Answer: 4. Uncomfortable.

Question 21. SO₂ pollution affects:

1. Nucleus
2. Mitochondria
3. Ribosomes
4. Vacuole.

Answer: 2. Mitochondria

Question 22. The Chornobyl nuclear tragedy occurred on which date?

1. 9th August 1943
2. 9th August 1945
3. April 1986
4. 3rd December 1984.

Answer: 3. April 1986

Question 23. Expand BOD:

1. Biological oxygen demand
2. Biosynthetic oxygen demand
3. Biogeochemical oxygen destroyer
4. Biogeochemical oxygen dimension.

Answer: 1. Biological oxygen demand

Water Pollution Sources And Control Measures NEET

Question 24. The term ‘Bio-magnification’ refers to the:

1. Growth of organisms due to food consumption
2. Increase in population size
3. Blowing up of environmental issues by man
4. Increase in cone, of non-degradable pollutants as they pass through the food chain.

Answer: 4. Increase in a cone, of non-degradable pollutants as they pass through the food chain.

Question 25. This acts as a bioindicator of air pollution:

1. Alga
2. Lichen
3. Pinus
4. Mustard
5. Fern.

Answer: 2. Lichen

Question 26. In 1984, the Bhopal gas tragedy took place because methyl isocyanate:

1. Reacted with ammonia
2. Reacted with CO₂
3. Reacted with water
4. Reacted with DDT.

Answer: 3. Reacted with water

Question 27. Lead cone, in blood is considered alarming if it is:

1. 30 μg/100 ml
2. 4-6 μg/100 ml
3. 10 μg/100 ml
4. 20 μg/100 ml.

Answer: 2. 4-6 μg/100 ml

Question 28. Blood analysis of a patient reveals a usually high quantity of carboxyhaemoglobin content. Which of the following conclusions is most likely to be correct? The patient has been inhaling polluted air containing unusually high content of:

1. Chloroform
2. Carbon dioxide
3. Carbon monoxide
4. Carbon disulphide.

Answer: 3. Carbon monoxide

Question 29. Escherichia coli is used as an indicator organism to determine pollution of water with:

1. Industrial effluents
2. Pollen of aquatic plants
3. Heavy metals
4. Faecal matter.

Answer: 4. Faecal matter.

Question 30. Which of the following is considered most effective in developing roads:

1. Bitumen and plastic
2. Plastic and polyblend
3. Bitumen and polyblend
4. Bitumen and recycled e-waste.

Answer: 3. Bitumen and polyblend

Question 31. Pollution of SO₂ destroys:

1. Lichen
2. Fungi
3. Algae
4. Fishes.

Answer: 1. Lichen

Question 32. A lake with an inflow of domestic sewage rich in organic waste may result in:

1. Death of fish due to lack of oxygen
2. Death of lake very soon due to algal bloom
3. Increased production of fish due to a lot of nutrients
4. Increased population of aquatic web organisms.

Answer: 1. Death of fish due to lack of oxygen

Question 33. Nitrogen oxides produced from the emission of automobiles and power plants are the sources of fine airborne particles which lead to:

1. Industrial smog
2. Diy acid deposition
3. Wet acid deposition
4. Photochemical smog.

Answer: 4. Photochemical smog.

Water Pollution Sources And Control Measures NEET

Question 34. The noise produced in the office is normally at the level of:

1. 20 db
2. 30 db
3. 40 db
4. 60 db.

Answer: 4. 60 db.

Question 35. Photosynthetic Active Radiation (PAR) has the following range of wavelengths:

1. 400 – 700 nm
2. 450 – 950 nm
3. 340 – 450 nm
4. 500 – 600 nm.

Answer: 1. 400 – 700 nm

Question 36. Which of the following is not used for disinfection of drinking water?

1. Phenyl
2. Chloramine
3. Chlorine
4. Ozone.

Answer: 2. Chloramine

Question 37. Which one of the following pairs is mismatched?

1. Biomass burning – release of CO₂
2. Fossil fuel burning – release of CO₂
3. Nuclear power  – radioactive wastes
4. Solar energy – the greenhouse effect.

Answer: 4. Solar energy – the greenhouse effect.

Question 38. Identify the correctly matched pair

1. Kyoto Protocol — Climatic change
2. Montreal Protocol — Global warming
3. Ramsar Convention — Groundwater pollution
4. Basal Convention — Biodiversity conservation.

Answer: 1. Kyoto Protocol — Climatic change

Question 39. Formation of non-functional methaemoglobin causes blue-baby syndrome. This is due to:

1. Deficiency of iron in food
2. Excess of nitrates in drinking water
3. Increased methane content in the atmosphere.
4. Excess of arsenic concentration in the drinking water.

Answer: 2. Excess of nitrates in drinking water

Solid Waste Management Strategies NEET Study Material

Question 40. Which one of the following statements pertaining to pollutants is correct?

1. DDT is a non-biodegradable pollutant
2. Excess fluoride in drinking water causes osteoporosis
3. Excess cadmium in drinking water causes black foot disease
4. Methylmercury in water may cause “Itai-itai” disease.

Answer: 1. DDT is a non-biodegradable pollutant

Question 41. Match the following and choose the correct combination from the options given:

1. 1 = D, 2 = C, 3 = B, 4 = A
2. 1 = A, 2 = C, 3 = B, 4 = D
3. 1 = C, 2 = C, 3 = D, 4 = A
4. 1 = C, 2 = B, 3 = A, 4 = A
5. 1 = C, 2 = D, 3 = A, 4 = B.

Answer: 4. 1 = C, 2 = D, 3 = A, 4 = B.

Question 42. Examples of regional pollution are:

1. Acid rain
2. Smog
3. Both (1) and (2)
4. None of these.

Answer: 3. Both (1) and (2)

Question 43. The greenhouse effect is due to:

1. CFC + N₂
2. CFC + CO
3. CFC + O₂
4. CFC + CO₂

Answer: 4. CFC + CO₂

Question 44. Due to industrialization since 1940 how much per cent of CO₂ is increased in the environment?

1. 10%
2. 5%
3. 20%
4. 15%.

Answer: 1. 10%

Question 45. The greenhouse effect is the cumulative result of the influences of certain gases. Identify the gas which is not involved in this influence:

1. Methane
2. Nitrogen
3. Carbon dioxide
4. Chlorofluorocarbon.

Answer: 2. Nitrogen

Question 46. Montreal Protocol which calls for appropriate action to protect the ozone layer from human activities passed in the year:

1. 1985
2. 1986
3. 1988
4. 1987.

Answer: 4. 1987.

Question 47. The limit of BOD prescribed by the Central Pollution Control Board for the discharge of industrial and municipal wastewater into natural surface waters is:

1. < 100 ppm
2. < 30 ppm
3. < 10 ppm
4. < 3.0 ppm.

Answer: 2. < 30 ppm

Question 48. Photochemical smog pollution does not contain:

1. Carbon dioxide
2. PAN (peroxy acyl nitrate)
3. Ozone
4. Nitrogen dioxide.

Answer: 1. Carbon dioxide

Solid Waste Management Strategies NEET Study Material

Question 49. Which of the following strategies is not a correct approach to reduce global warming?

1. Reducing greenhouse gas emissions by limiting the use of fossil fuels
2. Increase the vegetation cover particularly the forest for photosynthetic utilization of CO₂
3. Minimizing the use of nitrogen “fertilizers in agriculture for reducing N₂Oemission
4. Increasing the use of air conditioners, refrigeration units and production of plastic foams and propellants in aerosol spray cans.
5. Developing substitutes for chlorofluorocarbons.

Answer: 4. Developing substitutes for chlorofluorocarbons.

Question 50. Match the following items in column A with column B and choose the correct answer.

1. 1 – B, 2 – C, 3 – E, 4 – A, 5 – D
2. 1 – E, 2 – C, 3 – A, 4 – B, 5 – D
3. 1 – C, 2 – C, 3 – E, 4 – A, 5 – B
4. 1 – E, 2 – D, 3 – C, 4 – B, 5 – A
5. 1 – B, 2 – E, 3 – D, 4 – C, 5 – A

Answer: 3. 1 – C, 2 – C, 3 – E, 4 – A, 5 – B

Question 51. Pollution from animal excreta and organic waste from the kitchen can be most profitably minimized by:

1. Storing them in underground storage tanks
2. Using them for producing biogas
3. Vermiculture
4. Using them directly as biofertilizers.

Answer: 2. Using them for producing biogas

Question 52. The Montreal Protocol refers to:

1. Persistent organic pollutants
2. Global wasting acid climate change
3. Substances that deplete the ozone layer
4. Biosafety of genetically modified organisms.

Answer: 3. Substances that deplete the ozone layer

Question 53. Which one of the following is an environment-related disorder with the correct main cause?

1. Black lung disease (pneumoconiosis) found mainly in workers in stone quarries and crushers
2. Blue baby disease (methaemoglobinaemia) due to heavy use of nitrogenous fertilizers in the area
3. Non-Hodgkin’s Lymphoma is found mainly in workers involved in the manufacture of neem-based pesticides
4. Skin cancer is mainly in people exposed to benzene and methane.

Answer: 1. Black lung disease (pneumoconiosis) is found mainly in workers in stone quarries and crushers

Question 54. In which one of the following the BOD (Biochemical Oxygen Demand) of sewage (S), distillery effluent (DE), paper mill effluent (PE) and sugar mill effluent (SE) have been arranged in ascending order?

1. SE < PE < S < DE
2. PE < S < SE < DE
3. S < DE < PE < SE
4. SE < S < PE < DE.

Answer: 2. PE < S < SE < DE

Question 55. In a coal-fired power plant, electrostatic precipitators are installed to control the emission of:

1. NO_X
2. SPM
3. CO
4. SO₂

Answer: 2. SPM

Question 56. Ultrasound of how much frequency is beamed into the human body for sonography?

1. 15-30 MHz
2. 1-15 MHz
3. 45-70 MHz
4. 30-45 MHz.

Answer: 2. 1-15 MHz

Question 57. Which one of the following is not a bioindicator of water pollution?

1. Blood-worms
2. Stone flics
3. Sewage fungus
4. Sludge-worms.

Answer: 2. Stone flics

Question 58. An increase of BOD in water leads to:

1. Increase in the dissolved O₂ concentration
2. Increase in the dissolved  O₂ concentration
3. Maintenance of dissolved O₂ concentration at the same level
4. No effect on dissolved O₂ concentration.

Answer: 2. Increase in the dissolved O₂ concentration

Question 59. Freon gas causing stratospheric O₂ depletion is mainly released from:

1. Refrigerator
2. Automobile
3. Thermal Power Plant
4. Steel Industry.

Answer: 1. Refrigerator

Solid Waste Management Strategies NEET Study Material

Question 60. Mercury pollution causes

1. Black foot disease
2. Itai-itai disease
3. Blue-baby syndrome
4. Minamata disease
5. Skeletal fluorosis.

Answer: 4. Skeletal fluorosis.

Question 61. Which one of the following is the correct percentage of the two (out of the total of 4) greenhouse gases that contribute to the total global warming?

1. N₂O6%,CO₂86%
2. CO₂40%,CFCs30%
3. Methane 20%, N₂O18%
4. CFCs 14% methane 20%.

Answer: 4. CFCs 14% methane 20%.

Question 62. A lake near a village suffered heavy mortality of Fish within a few days. Consider the following reasons for this:

1. Lots of urea and phosphate fertilizers were used in the crops in the vicinity.
2. The area was sprayed with DDT by an aircraft
3. The lake was turned green and stinky.
4. Phytoplankton populations in the lake declined initially thereby greatly reducing photosynthesis.

1. 1 and 2
2. 2 and 3
3. 3 and 4
4. 1 and 3.

Answer: 2. 2 and 3

Question 63. Which one of the following pairs of gases is the major cause of the “Greenhouse effect”?

1. CO₂ and O₃
2. CO₂ and CO
3. CFCs and SO₂
4. CO₂ and N₂O

Answer: 4. CO₂ and N₂O

Question 64. Eutrophication is often seen in:

1. Deserts
2. Freshwater lakes
3. Ocean
4. Mountains.

Answer: 2. Freshwater lakes

Question 65. Which one of the following statements is wrong in the case of the Bhopal tragedy?

1. Methyl Isocyanate gas leakage took place
2. Thousands of human beings died
3. Radioactive fallout engulfed Bhopal

Answer: 3. Radioactive fallout engulfed Bhopal

Question 66. In an area where DDT had been used extensively, the population of birds declined significantly because:

1. Earthworms in the area were eradicated
2. Cobras were feeding exclusively on birds
3. Many of the bird’s eggs laid did not hatch
4. Birds stopped laying eggs.

Answer: 3. Many of the bird’s eggs laid did not hatch

Question 67. The Kyoto Protocol was endorsed at:

1. CoP – 5
2. CoP – 6
3. CoP – 4
4. CoP – 3.

Answer: 4. CoP – 3.

Question 68. Autecology is the:

1. Relation of a population to its environment
2. Relation of an individual to its environment
3. Relation of a community to its environment
4. Relation of a biome to its environment.

Answer: 2. Relation of an individual to its environment

Question 69. Ecotone is:

1. A polluted area
2. The bottom of a lake
3. A zone of transition between two communities
4. A zone of developing community.

Answer: 3. A zone of transition between two communities

Greenhouse Effect And Global Warming NEET Exam Preparation

Question 70. Biosphere is:

1. A component of the ecosystem
2. Composed of the plants present in the soil
3. Life in outer space
4. Composed of all living organisms present on Earth which interact with the physical environment.

Answer: 4. Composed of all living organisms present on earth which interact with the physical environment.

Question 71. The ecological niche is:

1. The surface area of the ocean
2. An ecologically adapted zone
3. The physical position and functional role of a species within the community
4. Formed of all plants and animals living at the bottom of a lake.

Answer: 3. The physical position and functional role of a species within the community

Question 72. According to Allen’s Rule, the mammals from colder climates have:

1. Shorter ears and longer limbs
2. Longer ears and shorter limbs
3. Longer ears and longer limbs
4. Shorter ears and shorter limbs.

Answer: 4. Shorter ears and shorter limbs.

Question 73. Salt concentration (Salinity) of the sea measured in parts per thousand is:

1. 10-15
2. 30-70
3. 0-5
4. 30-35.

Answer: 4. 30-35.

Question 74. Formation of tropical forests needs mean annual temperature and mean annual precipitation as:

1. 18 – 25°C and 150 – 400 cm
2. 5 – 15°C and 50 – 100 cm
3. 30 – 50°C and 100 – 150 cm
4. 5 – 15°C and 100 – 200 cm.

Answer: 1. 18 – 25°C and 150 – 400 cm

Question 75. Which of the following forest plants controls the light conditions at the ground?

1. Lianas and climbers
2. Shrubs
3. Tall trees
4. Herbs.

Answer: 3. Tall trees

Question 76. What will happen to a well-growing herbaceous plant in the forest if it is transplanted outside the forest in a park?

1. It will grow normally
2. It will grow well because it is planted in the same locality
3. It may not survive because of changes in its microclimate
4. It grows very well because the plant gets more sunlight.

Answer: 3. It may not survive because of changes in its microclimate

Question 77. If a population of 50 Paramoecium present in a pool increases to 150 after an hour, what would be the growth rate of the population?

1. 50 per hour
2. 200 per hour
3. 5 per hour
4. 100 per hour.

Answer: 4. 100 per hour

Question 78. What would be the per cent growth or birth rate per individual per hour for the same population?

1. 100
2. 200
3. 50
4. 150.

Answer: 2. 200

Question 79. A population has more young individuals compared to older individuals. What would be the status of the population after some years?

1. It will decline
2. It will stabilise
3. It will increase
4. It will first decline and then stabilise.

Answer: 3. It will increase

Question 80. What parameters are used for tiger census in our country’s national parks and sanctuaries?

1. Pug marks only
2. Pug marks and faecal pellets
3. Faecal pellets only
4. Actual head counts.

Answer: 2. Pug marks and faecal pellets

Question 81. Which of the following would necessarily decrease the density of a population in a given habitat?

1. Natality > mortality
2. Immigration > emigration
3. Mortality and emigration
4. Natality and immigration.

Answer: 3. Mortality and emigration

Question 82. A protozoan reproduces by binary fission. What will be the number of protozoans in its population after six generations?

1. 128
2. 24
3. 64
4. 32.

Answer: 3. 64

Question 83. In 2005, for each of the 14 million people present in a country, 0.028 were born and 0.008 died during the year. Using the exponential equation, the number of people present in 2015 is predicted as:

1. 25 million
2. 17 million
3. 20 million
4. 18 million.

Answer: 2. 17 million

Greenhouse Effect And Global Warming NEET Exam Preparation

Question 84. Amensalism is an association between two species where:

1. One species is harmed and another is benefited
2. One species is harmed and the other is unaffected
3. One species is benefited and the other is unaffected
4. Both species are harmed.

Answer: 2. One species is harmed and the other is unaffected

Question 85. Lichens are the associations of:

1. Bacteria and fungus
2. Algae and bacterium
3. Fungus and algae
4. Fungus and virus.

Answer: 3. Fungus and algae

Question 86. Which of the following is a partial root parasite?

1. Sandalwood
2. Mistletoe
3. Orobanche
4. Ganoderma.

Answer: 2. Mistletoe

Question 87. Which one of the following organisms reproduces sexually only once in its lifetime?

1. Banana plant
2. Mango
3. Tomato
4. Eucalyptus.

Answer: 4. Eucalyptus.

Question 88. Decomposers like fungi and bacteria are:

1. Autotrophs
2. Heterotrophs
3. Saprotrophs
4. Chemo-autotrophs

Choose the correct answer

1. 1 and 3,
2. 1 and 4
3. 2 and 3
4. 1 and 2

Answer: 3. 2 and 3

Question 89. The process of mineralisation by microorganisms helps in the release of:

1. Inorganic nutrients from humus
2. Both organic and inorganic nutrients from detritus
3. Organic nutrients from humus
4. Inorganic nutrients from detritus and the formation of humus.

Answer: 1. Inorganic nutrients from humus

Question 90. Productivity is the rate of production of biomass expressed in terms of:

1. (kcal m^-3) yr^-1
2. g^-2 yr^-1
3. g^-1 yr^-1
4. kcal m^-2 yr^-1

1. 2,
2. 3,
3. 2 and 4
4. 1 and 3.

Answer: 3. 2 and 4

Environmental Issues NEET Notes

Question 91. An inverted pyramid of biomass can be found in which ecosystem?

1. Forest
2. Marine
3. Grassland
4. Tundra.

Answer: 2. Marine

Question 92. Which of the following is not a producer?

1. Spirogyra
2. Agaricus
3. Volvox
4. Nostoc.

Answer: 2. Agaricus

Question 93. Which of the following ecosystems is most productive in terms of net primary production?

1. Deserts
2. Tropical rain forests
3. Oceans
4. Estuaries.

Answer: 2. Tropical rainforests

Question 94. The pyramid of numbers is

1. Always upright
2. Always inverted
3. Ether upright or inverted
4. Neither upright nor inverted.

Answer: 3. Ether upright or inverted

Question 95. Approximately how much of the solar energy that falls on the leaves of a plant is converted to chemical energy by photosynthesis?

1. Less than 1%
2. 2 – 10%
3. 30%
4. 50%.

Answer: 2. 2 – 10%

Question 96. Among the following, where do you think the process of decomposition would be the fastest?

1. Tropical rain forest
2. Antarctic
3. Dry arid region
4. Alpine region.

Answer: 1. Tropical rainforest

Question 97. How much of the net primary productivity of a terrestrial ecosystem is eaten and digested by herbivores?

1. 1%
2. 10%
3. 40%
4. 90%.

Answer: 2. 10%

Question 98. During the process of ecological succession, the changes that take place in communities are:

1. Orderly and sequential
2. Random
3. Very quick.
4. Not influenced by the physical environment

Answer: 1. Orderly and sequential

Question 99. Climax community is in a state of:

1. Non-equilibrium
2. Equilibrium
3. Disorder
4. Constant change.

Answer: 2. Equilibrium

Question 100. Among the following biogeochemical cycles which one does not have losses due to respiration?

1. Phosphorus
2. Nitrogen
3. Sulphur
4. All of the above.

Answer: 4. All of the above.

Environmental Issues NEET Notes

Question 101. The sequence of communities of primary succession in water is:

1. Phytoplankton, Sedges, Free-Floating Hydrophytes, Rooted Hydrophytes, Grasses And Trees.
2. Phytoplankton, Free-Floating Hydrophytes, Rooted Hydrophytes, Sedges, Grasses And Trees.
3. Free-floating hydrophytes, Sedges, Phytoplankton, Rooted Hydrophytes, Grasses And Trees.
4. Phytoplankton, Rooted Submerged Hydrophytes, Floating Hydrophytes, Reed Swamp, Sedges, Meadow And Trees.

Answer: 4. Phytoplankton, Rooted Submerged Hydrophytes, Floating Hydrophytes, Reed Swamp, Sedges, Meadow And Trees.

Question 102. The reservoir for the gaseous type of bio-geochemical cycle exists in

1. Stratosphere
2. Atmosphere
3. Ionosphere
4. Lithosphere.

Answer: 2. Atmosphere

Question 103. If the carbon atoms fixed by producers already have passed through three species, the trophic level of the last species would be.

1. Scavenger
2. Tertiary producer
3. Tertiary consumer
4. Secondary consumer.

Answer: 3. Tertiary consumer

Question 104. Which of the following types of ecosystem is expected in an area where evaporation exceeds precipitation, and mean annual rainfall is below 100mm?

1. Grassland
2. Shrubby forest
3. Desert
4. Mangrove.

Answer: 3. Desert

Question 105. The zone at the edge of a lake or ocean which is alternatively exposed to air and immersed in water is called:

1. Pelagic zone
2. Benthic zone
3. Lentic one
4. Littoral zone.

Answer: 4. Littoral zone.

Question 106. Edaphic factor refers to:

1. Water
2. Soil
3. Relative humidity
4. Altitude.

Answer: 2. Soil

Question 107. Which of the following is an ecosystem service provided by a natural ecosystem?

1. Cycling of nutrients
2. Prevention of soil erosion
3. Pollutant absorption and reduction of the threat of global warming
4. All of the above.

Answer: 4. All of the above.

Question 108. Which of the following countries has the highest biodiversity?

1. Brazil
2. South Africa
3. Russia
4. India.

Answer: 1. Brazil

Question 109. Which of the following is not a cause for the loss of biodiversity?

1. Destruction of habitat
2. Invasion by alien species
3. Keeping animals in zoological parks
4. Over-exploitation of natural resources.

Answer: 3. Keeping animals in zoological parks

Question 110. Which of the following is not an invasive alien species in the Indian context?

1. Lantana
2. Cynodon
3. Parthenium
4. Eichhornia.

Answer: 2. Cynodon

Question 111. Where among the following will you find pitcher plants?

1. Rain forest of North-East India
2. Sunderbans
3. Thar Desert
4. Western Ghats.

Answer: 1. Rain forest of North-East India

Question 112. Which one of the following is not a major characteristic feature of biodiversity hotspots?

1. A large number of species
2. Abundance of endemic species
3. A large number of exotic species
4. Destruction of habitat.

Answer: 4. Destruction of habitat.

Question 113. Match the animals given in column A with their location in column B:

Choose the correct match from the following:

1. 1-A, 2-C, 3-B, 4-D
2. 1-D, 2-C, 3-A, 4-B
3. 1-C, 2-A, 3-B, 4-D
4. 1-C, 2-A, 3-D, 4-B.

Answer: 4. 1-C, 2-A, 3-D, 4-B.

Question 114. What is common to the following plants: Nepenthes, Psilotum, Ramvolfia and Aconitum?

1. All are ornamental plants
2. All are phylogenic link species
3. All are prone to over-exploitation
4. All are exclusively present in the Eastern Himalayas.

Answer: 3. All are prone to over-exploitation

Question 115. The one-homed rhinoceros is specific to which of the following sanctuaries?

1. Bhitar Kanika
2. Bandipur
3. Kaziranga
4. Corbett park.

Answer: 3. Kaziranga

Question 116. Amongst the animal groups given below, which one has the highest percentage of endangered species?

1. Insects
2. Mammals
3. Amphibians
4. Reptiles.

Answer: 3. Amphibians

Question 117. Which one of the following is an endangered plant species of India?

1. Rauwolfia serpentina
2. Santalwn album (Sandalwood)
3. Cycas be done
4. All of the above.

Answer: 4. All of the above.

Question 118. Non-biodegradable pollutants are created by:

1. Nature
2. Excessive Use Of Resources
3. Humans
4. Natural Disasters.

Answer: 3. Humans

Question 119. According to the Central Pollution Control Board, particles that are responsible for causing great harm to human health are of diameter:

1. 2.50 micrometres
2. 5.00 micrometres
3. 10.00 micrometres
4. 7.5 micrometres.

Answer: 1. 2.50 micrometres

Question 120. The material generally used for soundproofing of rooms like a recording studio and auditoriums, etc. is:

1. Cotton
2. Coir
3. Wood
4. Styro Foam.

Answer: 4. Styro Foam.

Question 121. Compressed Natural Gas (CNG) is:

1. Propane
2. Methane
3. Ethane
4. Butane.

Answer: 2. Methane

Question 122. The world’s most problematic aquatic weed is:

1. Azolla
2. Woljjia
3. Economia
4. Trapa.

Answer: 3. Eichomia

Question 123. Which of the following causes biomagnification?

1. SO₂
2. Mercury
3. DDT
4. Both 2 and 3

Answer: 4. Both 2 and 3

Question 124. The expanded form of DDT is:

1. Dichloro Diphenyl Trichloroethane
2. Dichloro Diethyl Trichloroethane
3. Dichloro Dipyrydyl Trichloroethane
4. Dichloro Diphenyl Tetrachloroacetate.

Answer: 1. Dichloro Diphenyl Trichloroethane

Question 125. Which of the following materials takes the longest time for biodegradation?

1. Cotton
2. Paper
3. Bone
4. Jute.

Answer: 3. Bone

Question 126. Choose the incorrect statement.

1. The Montreal Protocol is associated with the control of the emission of ozone-depleting substances
2. Methane and carbon dioxide are greenhouse gases
3. Dobson units are used to measure oxygen content
4. The use of incinerators is crucial to the disposal of hospital waste.

Answer: 3. Dobson units are used to measure oxygen content

Question 127. Among the following which one causes more indoor chemical pollution?

1. Burning coal
2. Burning cooking gas
3. Burning mosquito coil
4. Room spray.

Answer: 3. Burning mosquito coil

NEET Biology Principles And Processes Of Biotechnology

It pertains to the industry of advancements in research procedures and instruments within the biological sciences.

• The genesis of biotechnology is rooted in the depths of human history. At the inception of civilization, alcohol derived from fermented steep liquor or plant juices was likely the earliest result of biotechnology.
• Biotechnology is the application of biological organisms or their derivatives in industrial operations.
• Modern biotechnology refers specifically to techniques and production technol
• ogies that entail genetic engineering.
• The European Federation of Biotechnology (EFB) characterizes biotechnology as the amalgamation of natural sciences with organisms, cells, their components, and molecular analogs for the development of products and services; it includes both conventional perspectives and contemporary molecular biology.

Some Of The Biotechnological Products And Processes Are

1. Recombinant DNA vaccines.
2. Synthesis of a gene and introduction of it into a target cell/organism.
3. Gene therapy.
4. In vitro fertilization for production of test tube babies.
5. Production of many biological compounds such as vaccines, antibodies vitamins, antibiotics, hormones, etc.

The organisms involved in industrial biotechnology may be as complex as cattle or as simple as a single-celled yeast (Saccharomyces cerevisiae.)

Read and Learn More NEET Biology Notes

Bioreactor: The fermentation tank where fermentation is carried out in the presence of micro-organisms.

Biotechnology is closely linked to the development in the 1970s of genetic engineering (the directed alteration of genetic material). Substances that have been produced in this manner include human interferon (a natural virus-fighting substance), human insulin, and human growth hormone.

• Biotechnology has advanced rapidly in the last two decades due to advances in biology, microbiology, biochemistry, immunology, molecular biology, genetic engineering, and chemical engineering.
• Any organism can be used in biotechnology, for example, cattle, pigs, sheep, horses, monkeys, yeast, and a large number of microorganisms. For better yield, it is imperative to select a suitable strain/variety and evolve a suitable technique for the extraction and purification of the product.
• The first use of biotechnology must have been in pre-historic times when humans discovered the fermentation of alcoholic beverages and dairy products.

Genetic Engineering: It is a technique for artificially and deliberately modifying DNA (genes) to suit human needs. It is also called recombinant DNA technology or DNA splicing. It is a kind of biotechnology.

Principles Of Biotechnology: The two core techniques that enabled the birth of modern biotechnology are

1. Genetic engineering technique of altering the nature or genetic material and/ or introducing it into another host organism to change its phenotype.
2. Techniques to facilitate tile growth and multiplication of only the desired microbes or cells in large numbers, under sterile conditions for the manufacture of biotechnological products.

Biotechnology Principles And Processes NEET Notes

Steps In Genetic Engineering (Recombinant DNA Technology)

1. Identification and isolation of agronomically important genes.
2. Cloning of isolated genes in a vector.
3. Introduction of the gene into plant protoplast cells/tissues with the use of gene transfer method.
4. Culture and regeneration of complete plant on suitable selection medium.
5. Integration of foreign genes in the transgenic plants by using molecular techniques.

With the help of restriction enzymes DNA is cut at specific sites and then joined with DNA of plasmids or phages. Then these plasmids or phages known as vectors are introduced into a bacterium. The process is known as transformation.

With the division of bacteria, desirable quantities of that particular DNA segment can be obtained. The key tools needed for the recombinant DNA technology to be accomplished are:

1. Cell culture with desired DNA
2. Restriction enzymes
3. DNA polymerase
4. Ligases
5. Vector (s)
6. Host organism/cell.

NEET Biology Principles And Processes Of Biotechnology Cloning Vectors

Vectors And Their Types: A vector is defined as a DNA molecule capable of self-replication and used as the carrier of DNA segments to be cloned (Gene). In an actual sense, it is required for transferring and cloning the gene in a suitable host or bacterium.

• The gene is inserted in the vector forming Recombinant DNA or Recombinant vector. The recombinant vector is also called the hybrid vector or chimeric vector (chimera = a mythological monster with a lion’s head, goat’s body, and serpent’s tail).
• The vectors can be cloning vectors i.e., those which isolate, characterize, and clone genes, or expression vectors i.e., those which not only allow multiplication (cloning) but may also be manipulated in such a way that the inserted gene may express in the host.

1. Use Of Plasmids as Genetic Material: Plasmids are obtained from bacteria. They are treated with restriction endonuclease enzyme to obtain the fragments of the desired genome. They are allowed to fuse with the help of DNA ligase enzyme. The recombinant plasmids thus formed are used as genetic material.
   • Plasmid: Additional DNA rings present in bacteria can be elaved by R.E. (Restriction Endonuclease), and can be joined with foreign DNA by ligase.
   • Ti plasmids of Agrobacterium and Ri plasmid of Agrobacterium rhizogenes are best-known vectors in higher plants.
   • The Plasmids Normally Used As The Vectors Are: The size of plasmids ranges from 1 x 10⁶ to 200 x 10⁶ daltons. These can be of the following types
     • Single copy plasmids i.e., those which occur one plasmid per cell.
     • Multiple copy plasmids i.e., those which occur 10 to 20 copies per cell.
     • There are also plasmids that, are under the relaxed replication control, thus permitting their accumulation in very large numbers i.e., up to 1000 copies per cell. These are the plasmids that we use for cloning purposes due to their increased yield potential.
2. Bacteriophage DNA: Lambda (X) phage is another very useful vector for Gene cloning in bacteria. Plasmid vectors described above are normally used to clone DNA segments of small size i.e., up to 10 kilo bases.
   • However, while preparing a genomic library for a eukaryote with quite large DNA fragments or even whole genomes the requirements of cloning are fulfilled by lambda phage derivatives used for transferring genetic material from one bacterium to the other.
   • From these cloning of 20-25 kilobases is possible. These consist of linear double-stranded DNA molecules which have been engineered in a way that their lytic cycle is possible but a lysogenic cycle is not possible.
   • The Lambda Phage Genome is λ about 50 kbp circular DNA. It follows either a lytic path or a lysogenic path. Lytic one may be switched towards lysogeny and vice versa. An important feature of the lambda genome is that only about 60% genome is required for the lytic growth of phage and the central 40% can be replaced by foreign DNA.
     • The percentage of foreign DNA can be increased also but a maximum up the 75-95% of the wild genome. This is made possible by removing some of the non-essential parts of the phage genome but only up to a certain limit.
   • The Lambda Cloning Vectors Are Of Two Types:
     • The insertion vector, which accepts inserts only 2 kbp long at a single multiple cloning site λ gt 10 and λ gt 11 vectors.
     • The replacement vectors, which accept inserts 9-23 kbp long with involvement of replacement of a non-essential part (stuffer) of the genome, for example, EMBL3 and EMBL4 vectors.
3. Plant And Animal Vectors.
4. Jumping Genes (Transposons)
5. Artificial Chromosomes Of Bacteria, Yeast, And Mammals.
6. Cosmids: These are the vectors that can accommodate DNA segments up to 45 kbp. These are actually plasmid particles to which specific DNA sequences, namely those for the cos sites are inserted.
   • Since the cos sites enable the DNA to be packed in the phage (λ) particle we can say that cosmids allow the packaging of DNA in phage in vitro thus permitting their purification.
   • Like plasmids, these cosmids also perpetuate in bacteria. The advantage of cosmids for cloning is that its efficiency is high enough to produce a complete genome library of 10⁶ – 10⁷ clones from a mere Img of insert DNA. The disadvantage is its inability to accept more than 40- 50 kbp of DNA.
7. Phagemids: These arc plasmids with a fragment of filamentous phage DNA, thus combining the desirable features of both.
   • Segments of foreign DNA cloned in them are multiplied as plasmid vectors, but when these plasmid vectors are infected with a filamentous phage called helper phage, the phagemid genome present already behaves like a phage.
   • As a result of this the phagemid generates multiple copies of one strand of it and the associated DNA inserted in it.
   • The single strand can be purified from these phage particles and used for:
     • Sequencing
     • Site-directed mutagenesis
     • Synthesis of strand-specific probes

Phagemids have been developed by inserting intergenic regions of a variety of filamentous phages into plasmids.

Origin Of Replication (Ori)

• This is a sequence of base pairs on DNA where replication starts.
• Any piece of DNA linked to this sequence can be made to replicate within the host cells.
• This sequence is also responsible for controlling the copy number of the linked DNA.

Biotechnology Principles And Processes NEET Notes

Selectable Marker

• A marker is a gene that helps in selecting those host cells that contain the vector (transformant) and eliminating the non-transformants.
• Common selectable markers for E. coli include the genes encoding resistance to antibiotics such as ampicillin. chloramphenicol, tetracycline, and kanamycin or the gene for β galactosidase which can be identified by a color reaction.

Enzymes Used In Genetic Engineering: The following Enzymes are used

1. Lysing Enzyme: It is used to open up cells to get DNA for genetic experiments. Lysoenzyme and Lysozyme arc are commonly used to dissolve bacterial cell walls.
2. Cleaving enzymes to break DNA molecules; of 3 types
   • Exonuclease cuts off nucleotides from 5′ or 3′ end.
   • Endonuclease cleaves DNA at any point except ends.
   • Restriction Endonuclease. It cleaves DNA duplex at specific points → Discovered by Arbern Nathans and Smith (1962) in Bacteria.
3. Uses Of Restriction Enzymes
   1. Restriction enzymes are used to cut a source DNA into small fragments for the isolation of a desired gene to be cloned.
   2. They are used to cut the vector DNAs at well-defined sites for cloning purposes.
   3. They are used to cut out unwanted sequences from natural vector DNAs to construct active vectors.
   4. They are used to cut a large DNA into small fragments for nucleotide sequencing.
   5. They are used to construct restriction maps of DNAs.
   6. They are used to cut DNAs to determine variant sequences among the DNAs of closely related individuals by restriction fragment length polymorphism (RELP).
4. DNA Polymerase. Help in the formation of DNA strands on DNA template.
5. Joining Enzyme (Ligase): Join and reseal the gaps in DNA fragments.

Fragmentation DNA: Fragmentation of DNA is carried out by incubating the purified. DNA molecules with suitable restriction enzymes at optimal conditions of temperature anil pH.

Biotechnology Principles And Processes NEET Study Material

Isolation Of DNA (Gene) Of Interest

• The fragments of DNA are separated by a technique called gel electrophoresis.
• The DNA is cut into fragments by restriction endonucleases.
• These fragments are separated by a technique called gel electrophoresis.
• Agarose, a natural polymer obtained from seaweeds is used as the matrix.
• DNA fragments being negatively charged, are separated by forcing them to move through the matrix towards the anode under an electric field.
• The DNA fragments separate/resolve according to their size.
• The separated molecules are stained by ethidium bromide and visualized by exposure to UV- radiation, as bright orange colored bands.
• The separated bands of DNA (on the gel) are cut from the gel and extracted from the gel piece (elution).
• Such DNA fragments are purified and used for constructing recombinant DNA by joining them with cloning vectors.

Amplification Of The DNA/Gene Of Interest.

• Amplification refers to the process of making multiple copies of the DNA segment in vitro.
• It employs polymerase chain reaction (PCR).
• The process was designed by K. Mullis.
• This technique involves three main steps :
  1. Denaturation
  2. Primer annealing and
  3. Extension of primers.
• The double-stranded DNA is denatured by using high temperatures.
• Two sets of primers are used; primers are the chemically synthesized short segments of DNA (oligonucleotides), that are complementary to the segment of DNA (of interest).

Ligation Of The DNA Fragment With The DNA Of The Vector.

• After cutting the source DNA segment and the vector DNA (to make the space for source DNA), the two are mixed and incubated with ligase under suitable conditions.
• This results in the formation of recombinant DNA (rDNA)

Transfer Of Recombinant DNA Into The Host.

• The bacterial cells must be made competent to take up DNA; this is done by treating them with a specific concentration of calcium, that increases the efficiency with which DNA enters the cell through the pores in its cell wall.
• Recombinant DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice followed by placing them at 42°C and then putting them back on ice.
• Microinjection is a method in which the recombinant DNA is directly injected into the nucleus of the animal cell with the help of microneedles or micropipettes.
• Gene gun or biolistics is a method suitable for plant cells, where cells are bombarded with high-velocity microparticles of gold or tungsten coated with DNA.
• Disarmed pathogens are used as vectors; when they are allowed to infect the cell, they transfer the recombinant DNA into the host.

Culturing The Transgenic Cell.

• The cell containing the foreign gene (transgene) is cultured on a suitable medium.
• The cells multiply and make clones.

Extraction Of The Desired Product.

• The transgene expresses itself in the form of protein (s) under appropriate conditions.
• The product (s) can be extracted from the medium by employing a suitable procedure.
• Bioreactors are used for processing large volumes of culture to obtain the product of interest in sufficient quantities.

Biotechnology Principles And Processes NEET Study Material

Downstream Processing

• The product obtained is subjected to a series of processes (collectively called downstream processing) before it is made into a finished product ready for marketing.
• The two main processes are (1) separation and (2) purification.
• The product is then formulated with suitable preservatives.
• Such formulations have to undergo clinical trials, in the case of drugs.

Restriction Enzymes, Their Source, And The Target DNA Sequence With Cleavage Site

NEET Biology Principles And Processes Of Biotechnology Steps Of Genetic Engineering (RDNA Technology)

Isolation Of DNA

• DNA has to be isolated in pure form for the action of restriction enzymes.
• DNA can be released from the cells by digesting the cell envelope by the use of enzymes like lysozyme for bacterial cells, chitinase for fungal cells, and cellulose for plant cells.
• Since DNA is intertwined with histone proteins and RNAs, proteins are removed by treatment with proteases and RNAs by ribonucleases. o Other impurities are removed by employing suitable treatments.
• The purified DNA is precipitated by the addition of chilled ethanol; it is seen as a fine thread in suspension.

Importance Of Genetic Engineering Includes The Following :

• Gene Splicing: In Eukaryote, DNA is made up of exon (coding segment) and intron (Non-coding segment) or junk gene. This is also called the concept of split genes. It was discovered by RJ. Roberts and Phillip Sharp Nobel Prize in Physiology and Medicine (1993).
• As far as transcription is concerned, entire DNA is transcribed to form mRNA. (heterogeneous) mRNA : (heterogeneous mRNA); If segments of mRNA corresponding to intron are removed, and remaining mRNA segments (corresponding to exon) are joined together, the mRNA (fully translatable) is called processed or spliced RNA.

NEET Biology Principles And Processes Of Biotechnology Production Of Various Drugs And Chemicals

Numerous medications, vaccines, pharmacological agents for the treatment of diverse ailments, and hormones have been created via genetic engineering (recombinant DNA technology), with several currently undergoing release.

 A few are described below:

NEET Biology Principles And Processes Of Biotechnology DNA Cloning

To clone a specific gene, namely a DNA segment, it is essential to possess a pure fragment of DNA that encompasses that gene. There are various methods to acquire DNA. Single-stranded mRNA undergoes enzymatic conversion to double-stranded DNA. The resultant double-stranded DNA is termed complementary DNA (cDNA).

Biotechnology Principles And Processes NEET Question Bank

Clone DNA Can Be Obtained By

1. Separation of those segments of DNA which are to be cloned.
2. λ phage is used to join the DNA segment vector.
3. To get more of isolated clones these vectors and DNA segment is inserted in the host cell where the division it provides many copies of the wanted DNA segment.
4. Selection of wanted clone.
5. Store the clones in the Gene Bank.

• It is easy to prepare a clone when the size of DNA segment is 10kb or more otherwise recombination is difficult.
• According to Boffey (1987), to get a segment of 10kb DNA 1.5 x 10³ colonies are to be raised of the E. coli genome and in Homo sapiens, 2 x 10⁶ colonies are to be raised.
• To get more number of clones host cells are cultured in a culture medium and the wanted gene is separated by the use of a restriction enzyme and then stored.
• If a particular gene is needed, it is taken from the gene bank inserted into the vector, and taken to the host cell.

NEET Biology Principles And Processes Of Biotechnology Organism Cloning

Production of individuals having identical genetic makeup from one parent through asexual reproduction is the cloning of organisms. Clones are exact genetic replicas of an individual. Clones of plants, bacteria, and protozoa can be easily obtained by vegetative propagation and asexual reproduction.

The technique involves the artificial transplantation of the diploid nucleus into enucleated egg cells. These cells grow and develop into a young one similar to the parent whose diploid nucleus was transplanted.

Importance Of Cloning

1. New organisms with high and desired characteristics can be obtained in pure form.
2. Specific compounds for medicines that are made available by the specific organism can be obtained in high amounts by cloning.
3. Organs could be formed by cloning methods for transplantation so that they can be accepted by the human system without any rejection.
4. The main organs of transplantation are the Liver, Cornea, Heart, Kidney Skin, etc.
5. The success of animal cloning also has some adverse effects. Man has thought of producing human clones which is unethical and has adverse society, religion, and the law would not permit this as they are afraid of the time when a man can clone a criminal then what be the fate of society?

Biotechnology Principles And Processes NEET Question Bank

VNTRs (Variable Number Tandem Repeats). The VNTRs of two persons may be of the same length in the sequence at certain sites but vary at others. Half of the VNTRs of the child resemble that of the mother and the other half with that of the father.

• Gene Cloning: A foreign DNA (useful in genetic engineering) is combined with a vector and multiplied faithfully.
• Organism Cloning Nucleus of the ovum (IN) is removed and replaced by the nucleus of the diploid cell of the same organism. Now the egg with 2N nucleus is trans¬ferred to the uterus of the mother to have a normal pregnancy and delivers a clone of itself.
• Dr. Steven Stice and James of Advanced Cell Technology Corporation, Texas (USA), developed a technique for cloning genetically engineered calves that will be able to produce medicines for humans in their milk: The first cloned calves; George and Charlie were born in January 1998. Thus cloned cows are called Living Pharmaceutical factories (L.P.F.)

NEET Biology Principles And Processes Of Biotechnology Genomics

The term genomics was introduced by Thomas Roderick to describe the scientific discipline of mapping, sequences, and analysis of genes. In fact genomics is the study of genomes. All the DNA in the cells of an organism, say for our cells from skin or muscle or brain and everything including genes, is its genome.

Our body contains 100 million cells of over 260 different kinds. However, in most cases complete set of instructions in each is the same, needed to make a whole new human being. In all, there are 23 different chromosomes containing packed DNA in a haploid set of the human genome. Additional DNA is in the cell’s mitochondria which is inherited from one’s mother.

• Genomics is subdivided into structural genomics and functional genomics.
  • Structural Genomics is the study of genome structure and deals with the complete nucleotide sequences of organisms.
  • Functional Genomics is the study of genome function which includes transcriptome and proteome.
• Transcriptome is a complete set of RNAs transcribed from a genome.
• The proteome is a complete set of proteins encoded by a genome and aims at the deter¬mination of the structure and functions of all the proteins in living organisms.
• The nucleotide sequences of the genomes of two subspecies of rice were published in April 2002.
• The human body contains 100 million cells of over 260 different kinds.
• There is a complete set of instructions in each of the cells needed to make a whole new human being.
• There are 23 different chromosomes containing packed DNA in a haploid set of the human genome.
• Additional DNA is in the cell’s mitochondria which is inherited from one’s mother.

Revelations Of Genome: The details of the findings of our genome have revealed some startling facts. Being the most complex organism, we were expected to have more than 100,000 genes. Instead, the human gene count is much lower than expected, approximately 30,000 to 40,000 genes

Additional DNA is in the cell’s mitochondria which is inherited from one’s mother.

Biotechnology Principles And Processes NEET Mcqs

Revelations Of Genome: The details of the findings of our genome have revealed some startling facts. Being the most complex organism, we were expected to have more than 100,000 genes. Instead, the human gene count is much lower than expected, approximately 30,000 to 40,000 genes.

1. Bacteriophage: 10 thousand base pairs.
2. Escherichia coli: 4,7 million base pairs 4,000 genes.
3. Saccharomyces cerevisiae: 2 million base pairs 6,000 genes
4. Caenorhabditis elegans: 97 million base pairs 18,000 genes
5. Drosophila melanogaster: 180 million base pairs 13,000 genes
6. Human: 3 billion base pairs cells 30,000 genes
7. Lily: 106 billion base pairs per cell.

NEET Biology Principles And Processes Of Biotechnology Human Genome Protect

Additional DNA is in the cell’s mitochondria which is inherited from one’s mother. Many countries are working together with the National Institute of Health and Department of Energy USA., to decipher the human genome to know the position and function of each and every gene of the genome.

• Jean Dausset 1983 first thought about the human genome project. He worked on the Human Leucocyte antigen system (HLAS) helping in organ transplantation.
• The easiest way of getting DNA is by taking blood samples.
• The genome project was carried out by DNA mapping, DNA sequencing, and functional analysis of DNA.
• DNA mapping is done by using molecular markers. The simple sequence repeat is prepared and known as Sequence Tagged Site.
• DNA sequencing is known by the DNA sequence of the mouse. Small segments of DNA are taken and sequenced.
• Functional analysis of DNA is carried out by cDNA analysis of brain tissue, by computerized analysis of the sequence of genes, and by fixing the function of genes in the effect of mutation.
• The human genome has 22 pairs of autosomes and one pair of sex chromosomes. The genes are present in linear positions on chromosomes and approximately 1,00,000 genes are present in the genome.
• Renato Dulbecco (Virologist) of Italy started work on a human genome project in 1986.
• Nobel laureate Jean Dausset for the first time produced a genome map under a human genome project in 1994.
• The human genome is nearly deciphered by now (2000).
• Human beings are 99.9 percent identical with each other at the DNA level.
• Every alive human being is exactly the same and even bacteria are our cousins in code.
• Different human genes vary widely in length often over thousands of base pairs.
• While b-globin and insulin genes are less than 10 kilobase pairs, the gene responsible for Duchenne Muscular Dystrophy on ‘X’ chromosome is made up of 2400 kilo-base pairs which is probably the longest gene known.
• Though the lily plant produces fewer proteins than human beings, it has 18 times more DNA.
• Only less than 2 percent of the genome is known to include the exons, the protein-coding sequences.
• Approximately 1 million copies of short 5 to 8 base pair repeated sequences clustered around the centromeres and near the ends of the chromosomes represent ‘the junk DNA’.

NEET Biology Principles And Processes Of Biotechnology Gene Bank And Genomic Library

It is the collection of cloned DNA segments obtained from the complete genome. Gene bank is prepared by Shotgun experiments where the whole cell is stored as a random and unknown clone.

NEET Biology Principles And Processes Of Biotechnology Protein Engineering

The ability to change the amino acid sequence of a protein by altering the sequence of its cDNA is known as protein engineering.

• By site-directed mutagenesis technique, a new cDNA is created which is identical to the natural one except for changes designed by man.
• This DNA is used to generate protein in bacteria to transfect cell lines, or to create transgenic organisms.
• Protein engineering is used to study the proteins, to compare the catalytic properties of the normal and mutated form of an enzyme, etc.
• This technique is used to identify the particular charged amino acid residue responsible for the selectivity of ion channels.
• Nowadays protein engineering is used to generate a number of new proteins as a tool for scientific research, medical, and industrial purposes.

Biotechnology Principles And Processes NEET Mcqs

NEET Biology Principles And Processes Of Biotechnology Hybridoma Technology

Hybridoma is a hybrid cell obtained by the fusion of B-lymphocyte and cell (cell of antibody system of B-lymphocyte).

• Hybridoma cells can grow for an indefinite period and can produce antibodies because of the B-lymphocyte genome.
• Monoclonal antibodies are obtained from the in vitro culture of hybridoma cells.
• Hybridoma technology is developed in 1975 by G. Kohler and C. Milstein for which they were awarded the Nobel Prize in 1984.
• Antibodies obtained by this process are antigen-specific.

NEET Biology Principles And Processes Of Biotechnology DNA Fingerprinting

DNA Fingerprinting technique was developed by Alec Jeffreys (1985, 86) at Leicester University, United Kingdom.

Inheritance of DNA is very stable, Every person has a specific pattern of DNA sequence which shows a combination of the DNA sequence of both mother and father. The study of DNA fingerprints helps in the establishment of the identity of a person, the identification of criminals in case of murder or rape, and paternity tests in case of disputed parentage.

Principle of DNA Fingerprinting. It has been established that the DNA of a person carries some specific sequences of nucleotides that do not carry any information for proteins. Important for DNA typing profiling or fingerprinting are short nucleotide repeats that vary in number from person to person, but are inherited.

• These are the Variable Number Tandem Repeats or VNTRs. The VNTRs of two persons may be of the same length and sequence at certain sites but vary at others.
• In this example, a child might inherit a chromosome with six tandem repeats from the mother and the same tandem repeated four times in the homologous chromosome inherited from the father. Note that the half of VNTR alleles of the child resemble that of the mother and half that of the father.
• For DNA fingerprinting, DNA is isolated from any body cell or even from blood stains, semen stains, or hair roots. These cells are subjected to Southern blotting.
• In India first test of DNA fingerprinting was done in June 1989 to settle a disputed parentage in Madras. The laboratory for DNA fingerprinting is situated in Hyderabad at the Centre for Cell and Molecular Biology (CCMB).

Southern Blotting: A mixture of DNA fragments is separated by gel electrophoresis. DNA bands are denatured into single strands by an alkali solution. These DNA strands are fixed on the nitrocellulose membrane. This DNA is used for hybridization with the help of specific labeled DNA probes.

Then membrane is washed for any unbound DNA autoradiographs are taken and studied and DNA hybridization is done with the help of specific DNA probes. Polymorphism of DNA is revealed which shows very stable inheritance and is used for identification of a person.

Biotechnology Principles And Processes NEET Exam Preparation

Application Of DNA Fingerprinting

• Identify criminals in forensic laboratories.
• Determine paternity, who is the true biological father or mother of a child?
• Verify whether a hopeful immigrant is, as he or she claims, really a close relative of already an established resident.
• Identify racial groups to rewrite biological evolution.

DNA Footprinting. It is done to determine the location and lengths of binding sites of various proteins that bind to DNA. It is also possible to determine the sequence of the binding sites.

NEET Biology Principles And Processes Of Biotechnology Questions From Competitive Examinations

Question 1. Restriction endonucleases are used as:

1. Molecular build-up at nucleotides
2. Molecular degradation to DNA breakup
3. Molecular knives for cutting DNA at specific sites
4. Molecular cement to combine DNA sites.

Answer: 3. Molecular knives for cutting DNA at specific sites

Question 2. A somatic plant cell has the potential to develop into a full plant. This is called

1. Totipotency
2. Gene cloning
3. Tissue culture
4. Regeneration.

Answer: 1. Totipotency

Question 3. Enzymes breaking nucleic acids into nucleotides are called:

1. Hydrolases
2. Amylases
3. Nucleic acids
4. Nucleases.

Answer: 4. Nucleases.

Biotechnology Principles And Processes NEET Exam Preparation

Question 4. Recombinant DNA technology is related with:

1. Stanley Cohen and Harbert Boyer
2. Bateson and Punnet
3. Huxley and Harvey
4. Schleiden and Schwann.

Answer: 1. Stanley Cohen and Harbert Boyer

Question 5. Cosmid is:

1. Extragenetic material in Mycoplasma
2. Circular DNA in bacteria
3. Extra DNA in bacteria
4. Fragment of DNA inserted in bacteria for forming copies.

Answer: 4. Fragment of DNA inserted in bacteria for forming copies.

Question 6. Match the correct one

1. RNA Polymerase-RNA primer
2. Respiration-lysosome
3. Restriction enzyme-genetic engineering
4. Central dogma-DNA structure.

Answer: 3. Restriction enzyme-genetic engineering

Question 7. Plasmid is used as a carrier because:

1. It has both ends with replicating points
2. It has no free ends
3. It is circular DNA with the capacity to bind, with eukaryotic DNA
4. All Of the above.

Answer: 3. It is circular DNA with a capacity to bind, with eukaryotic DNA

Question 8. The Ti plasmid used in genetic engineering is obtained from:

1. Bacillus thuringeinsis
2. Agrobacterium rhizogenes
3. Agrobacterium tumifaciens
4. Escherichia coli.

Answer: 3. Agrobacterium tumefacient

Biotechnology Principles And Processes NEET Previous Year Questions

Question 9. The function of polymerase chain reaction (PCR) is:

1. Translation
2. Transduction
3. DNA amplification
4. None of these.

Answer: 3. DNA amplification

Question 10. The genetically engineered bacterium used in the production of:

1. Thyroxine
2. Human insulin
3. Epinephrine
4. Cortisol.

Answer: 2. Human insulin

Question 11. Abnormal gene is replaced by normal genes through:

1. Gene Therapy
2. Medicines
3. Cloning
4. Radiation.

Answer: 1. Gene Therapy

Question 12. In genetic engineering, the term vector is applied to:

1. Plasmid
2. Sources of DNA
3. Cell which receives
4. Virus.

Answer: 1. Plasmid

Question 13. Gene therapy involves

1. Introducing a normal gene in a cell
2. Eliminating defective and useless genes
3. Treating of defective genes with radiation
4. Replacement of defective genes with normal ones.

Answer: 4. Replacement of defective genes by normal ones

Question 14. Which of the following enzymes is used in genetic engineering?

1. Translocase
2. Topoisomerase
3. DNAse
4. Restriction endonuclease.

Answer: 4. Restriction endonuclease.

Question 15. The transgenic animals are those which have:

1. Foreign RNA in all its cell
2. Foreign DNA in all its cells
3. Foreign DNA in some of its cells
4. Both 1 and 3

Answer: 2. Foreign DNA in all its cells

Question 16. The known sequence of DNA that is used to find complementary DNA strands is:

1. Vector
2. Plasmid
3. DNA probe
4. Recombinant DNA.

Answer: 3. DNA probe

Question 17. Totipotency in the cell is:

1. Flower in a culture medium
2. Development of fruit from a flower in a culture medium
3. Development of an organism from a cell in a culture medium
4. Development of all tissues of all kinds from a cell in a culture medium.

Answer: 3. Development of an organism from a cell in a culture medium

Biotechnology Principles And Processes NEET Previous Year Questions

Question 18. The nuclease enzyme, which begins its attack from the free end of a polynucleotide, is?

1. Exonuclease
2. Kinase
3. Polymerase
4. Endonuclease.

Answer: 1. Exonuclease

Question 19. DNA fingerprinting method is very useful for:

1. DNA tests for identity and relationships
2. Forensic studies
3. Polymorphism
4. All of the above.

Answer: 4. All of the above.

Question 20. Reverse transcriptase:

1. Disintegrates host DNA
2. Translates host DNA
3. Transcribes viral RNA to DNA
4. Polymerises host DNA.

Answer: 3. Transcribes viral RNA to DNA

Question 21. Boviene spongiform encephalopathy disease is equal to:

1. KalaAzar
2. Parkinson’s disease.
3. Creutzfeldt-Jacob disease
4. None of the above.

Answer: 3. Creutzfeldt-Jacob disease

Question 22. A clone of sheep Dolly has been made by :

1. Gene transfer
2. Somatic cell cloning
3. Nucleus transfer
4. Germinal cell cloning.

Answer: 3. Nucleus transfer

Question 23. Which one of the following bacteria has found extensive use in genetic engineering work in plants?

1. Agrobacterium tumefaciens
2. Clostridium septicum
3. Xanthomonas citri
4. Bacillus coagulens.

Answer: 1. Agrobacterium tumefaciens

Question 24. Improvement of the genotype of an organism by the addition of some foreign genes is:

1. Genetic diversity
2. Gene handling
3. Tissue culture
4. Genetic engineering.

Answer: 1. Genetic diversity

Question  25. A variable number of tandem repeats (VTNRs) in the DNA molecule are highly useful in:

1. Monoclonal antibody production
2. DNA fingerprinting
3. Recombinant DNA technology
4. Stem cell culture.

Answer: 2. DNA fingerprinting

Question 26. The first clone animal of the world is:

1. Molly sheep
2. Polly sheep
3. Dolly sheep
4. Molly goat.

Answer: 1. Molly sheep

Question 27. In transgenics, the expression of transgene in the target tissue is known by:

1. Enhancer
2. Transgene
3. Promoter
4. Reporter.

Answer: 4. Reporter

Question 28. DNA fingerprinting is related to:

1. Molecular analysis of profiles of DNA samples
2. Analysis of DNA samples using imprinting devices
3. Techniques used for molecular analysis of different specimens of DNA
4. Techniques used in the identification of fingerprints of different persons.

Answer: 1. Molecular analysis of profiles of DNA samples

Question 29. Which of the following is specifically used in genetic engineering?

1. Ligase
2. Gyrase
3. DNA polymerase
4. Restriction endonuclease.

Answer: 4. Restriction endonuclease

Question 30. Molecular scissors, which cut DNA at specific sites:

1. Ligase
2. Cellulase
3. Pectinase
4. Polymerase.
5. Restriction endonuclease.

Answer: 3. Polymerase

Question 31. Plasmids are extrachromosomal circular DNA molecules:

1. Which have their own point of replication and can replicate independently
2. Which have their own point of replication but cannot replicate independently
3. Which do not have their own point of replication and cannot replicate independently of bacterial chromosomal DNA
4. None of the above.

Answer: 1. Which have their own point of replication and can replicate independently

Biotechnology Principles And Processes NEET Previous Year Questions

Question 32. Identify the plasmid:

1. Alu I
2. Hindffl
3. Eco RI
4. pBR 322.

Answer: 4. pBR 322.

Question 33. Natural genetic engineer is:

1. Bacillus subtillis
2. Pseudomonas spp.
3. Escherichia coli
4. Agrobacterium tumefaciens.

Answer: 4. Agrobacterium tumefaciens

Question 34. The most thoroughly studied of the known bacteria-plant interaction is the:

1. Plant growth simulation by phosphate-solubilising bacteria
2. Cyanobacterial symbiosis with some aquatic ferns
3. Gall formation on certain angiosperms by Agrobacterium
4. Nodulation of Sesbania stems by nitrogen-fixing bacteria.

Answer: 3. Gall formation on certain angiosperms by Agrobacterium

Question 35. What does Bt stand for the popular crop Bt cotton?

1. Best
2. Best type
3. Biotechnology
4. Bacillus tomentosa.
5. Bacillus thuringiensis.

Answer: 5. Bacillus thuringiensis

Question 36. DNA fingerprinting technique was first developed by:

1. Jeffreys, Wilson, and Thein
2. Schleiden and Schwann
3. Edward and Steptoe
4. Boysen and Jensen.

Answer: 1. Jeffreys, Wilson and Thein

Question 37. What is the first step in the Southern Blotting technique?

1. Isolation of DNA from a nucleated cell such as the one from the scene of crime
2. Denaturation of DNA on the gel for hybridization with a specific probe
3. Production of a group of genetically identical cells
4. Digestion of DNA by restriction enzyme.

Answer: 4. Digestion of DNA by restriction enzyme

Question 38. An example of gene therapy is:

1. Production of injectable hepatitis b vaccine
2. Production of vaccines in food crops like potatoes which can be eaten
3. Production of test tube babies by artificial insemination and implantation of fertilized eggs
4. Introduction of the gene for adenosine deaminase in persons suffering from severe combined immunodeficiency (SCID).

Answer: 4. Introduction of gene for adenosine deaminase in persons suffering from severe combined immunodeficiency (SCID)

Question 39. The total number of nitrogenous bases in human ge¬nome is estimated to be about:

1. 35 million
2. 3.1 billion
3. 3.5 million
4. 35 thousand.

Answer: 2. 3.1 billion

Question 40. The name of the drug used in cancer treatment produced by using biotechnology is:

1. HGH
2. TSH
3. Insulin
4. Interferon
5. Terramycin.

Answer: 4. Terramycin

Biotechnology Principles And Processes NEET Notes

Question 41. Which of the following pairs is correctly matched?

1. Central dogma-Codon
2. Okazaki fragments-Splicing
3. RNA polymerase-RNA primer
4. Restriction enzymes- Genetic engineering.

Answer: 2. Okazaki fragments-Splicing

Question 42. Tj plasmid is used for making transgenic plants. It is obtained from:

1. Azotobacter
2. Agrobacterium
3. Rhizobium in leguminous root
4. Yeast.

Answer: 2. Agrobacterium

Question 43. Somaclonal variation can be obtained by:

1. Hybridization
2. Tissue culture
3. Application of colchicine
4. Irradiation with gamma rays.

Answer: 2. Tissue culture

Question 44. The enzyme used for cutting DNA segments in genetic engineering is:

1. ATPase
2. Ligase
3. DNA polymerase
4. Restriction endonuclease.

Answer: 2. Restriction endonuclease

Question 45. Widely used tools in the genetic engineering of crop plants is:

1. Protoplast fusion
2. Transposon
3. Microinjection
4. Agrobacterium mediation.

Answer: 4. Agrobacterium mediation

Question 46. Which one of the following hydrolyses internal phosphodiester bonds in a polynucleotide chain?

1. Lipase
2. Protease
3. Exonuclease
4. Endonuclease.

Answer: 4. Endonuclease

Question 47. There is a restriction endonuclease called £coRI. What does the “co” part in it stand for?

1. Coli
2. Coelom
3. Coenzyme
4. Colon.

Answer: 1. Coli

Biotechnology Principles And Processes NEET Study Material

Question 48. Agarose extracted from seaweeds finds use in:

1. Spectrophotometry
2. Tissue culture
3. Gel electrophoresis
4. PCR.

Answer: 3. Gel electrophoresis

Question 49. Given below is a sample of a portion of the DNA strand giving the base sequence on the opposite strands. What is so special shown in it?

5′ _____ GAATTC _______ 3′

3′ ______ CTTAAG _______ 5′

1. Replication completed
2. Deletion mutation
3. Start codon at the 5’ end
4. The palindromic sequence of base pairs.

Answer: 4. Palindromic sequence of base pairs

Question 50. In DNA fingerprinting which of the following is true?

1. VNTR is used as a probes
2. Specific metabolic genes are used as probes
3. Housekeeping or luxury genes are used as probes
4. All of the above.

Answer: 1. VNTR is used as probes

Question 51. The matching sequence of DNA between two pieces of evidence, one of the criminals with the suspect is known as:

1. DNA fingerprinting
2. DNA amplification
3. Gene mapping
4. DNA resolution.

Answer: 1. DNA fingerprinting

Question 52. A technology which has found immense use in solving cases of disputed parentage is:

1. DNA fingerprinting
2. Polymerase chain reaction
3. Recombinant DNA technology
4. Monoclonal antibody production.

Answer: 1. DNA fingerprinting

Question 53. The first hormone prepared by genetic engineering is:

1. Insulin
2. Oxytocin
3. Adrenaline
4. Somatotropin.

Answer: 1. Insulin

Question 54. The first biochemical to be produced commercially by microbial cloning and genetic engineering is:

1. Interferon
2. Penicillin
3. Human insulin
4. Fertility factors.

Answer: 3. Human insulin

Question 55. Which of the following statements is true?

1. In the historic cloning experiment of Dr. Wilrnut, the transplanted nucleus was taken from an udder cell
2. Mammalian characters appeared first in dinosaurs
3. The heart of mammals is incapable of being in vitro
4. The pyramid of biomass is upright in the pond ecosystem.

Answer: 1. In the historic cloning experiment of Dr. Wilrnut, the transplanted nucleus was taken from an udder cell

Question 56. Protoplasts of two different species are fused in:

1. Dona propagation
2. Organography
3. Micropropagation
4. Somatic hybridization.

Answer: 4. Somatic hybridization

Biotechnology Principles And Processes NEET Question Bank

Question 57. cDNA probes are copied from the messenger RNA molecules with the help of:

1. Restriction enzymes
2. Reverse transcriptase
3. DNA polymerase
4. Adenosine deaminase.

Answer: 4. Adenosine deaminase

Question 58. The electroporation procedure involves:

1. Fast passage of food through sieve pores in phloem elements with the help of electric stimulation
2. Opening of stomatal pores during the night by artificial light
3. Making transient pores in the cell membrane to introduce gene constructs
4. Purification of saline water with the help of a membrane system.

Answer: 3. Making transient pores in the cell membrane to introduce gene constructs

Question 59. Which one of the following is a correct statement

1. “Bt” in “Bt-cotton” indicates that it is a genetically modified organism produced through biotechnol¬ogy
2. Somatic hybridization involves the fusion of two complete plant cells carrying desired genes
3. The anticoagulant hirudin is produced from transgenic Brassica napus seeds
4. The “Flavr Savr” variety of tomatoes has enhanced the production of ethylene which improves its taste.

Answer: 3. The anticoagulant hirudin is being produced from transgenic Brassica napus seeds

Question 60. A tumor-inducing plasmid widely used in the production of transgenic plants in that of:

1. Escherichia coli
2. Bacillus thuringiensis
3. Staphylococcus aureus
4. Agrobacterium tumefaciens.

Answer: 4. Agrobacterium tumefaciens

Question 61. The common bacterium used in genetic engineering is:

1. E. coli
2. Diplococcus
3. Rhizobium
4. Spirillium.

1. a = 3, b = 1, c = 5, d = 4
2. a = 1, b = 2,c = 3, d = 4
3. a = 2, b = 1, c = 3, d = 4
4. a = 4, b = 3, c = 1, d = 2
5. a = 3, b = 1, c = 5, d = 2.

Answer: 1. a = 3, b = 1, c = 5, d = 4

Question 62. Match The following and choose the correct combination from the options given:

Answer: 5

Question 63. Choose the correct statement with reference to ‘Dolly’:

1. She was created by taking the nucleus from unfertilized eggs and cytoplasm from unfertilized eggs
2. She was created by taking the nucleus from udder cells and cytoplasm from unfertilized eggs
3. She was created by taking cytoplasm from udder cell and nucleus from unfertilized eggs
4. She was created by taking cytoplasm from udder cell and nucleus from fertilized eggs
5. She was created inside the test tube.

Answer: 2. She was created by taking the nucleus from udder cells and cytoplasm from unfertilized eggs

Question 64. Find the incorrect statement:

1. Gene therapy is a genetic engineering technique used to treat disease at the molecular level by replacing defective genes with normal genes
2. Calcitonin is a medically useful recombinant product in the treatment of infertility
3. Bt toxin is a biodegradable insecticide obtained from Bacillus thuringiensis
4. Trichoderma sp. is a biocontrol agent for fungal diseases of plants
5. Totipotency is the potential ability of a cell to develop into a complete plant.

Answer: 2. Calcitonin is a medically useful recombinant product in the treatment of infertility

Question 65. Production of a human protein in bacteria by genetic engineering is possible because:

1. Bacterial cell can carry out the rna splicing reactions
2. The human chromosome can replicate in bacterial cell
3. The mechanism of gene regulation is identical in humans and bacteria
4. The genetic code is universal.

Answer: 4. The genetic code is universal

Question 66. Two microbes found to be very useful in genetic engineering are:

1. Diplococcus sp. and Pseudomonas sp.
2. Crown gall bacterium and Caenorhabditis elegans
3. Escherichia coli and Agrobacterium tumefaciens

Answer: 3. Escherichia coli and Agrobacterium tumefaciens

Question 67. What is the function of Restriction endonuclease?

1. Restricts the synthesis of DNA inside the nucleus
2. Synthesizes DNA
3. Cuts the DNA molecule randomly
4. Cuts the DNA molecule at specific sites.

Answer: 4. Cuts the DNA molecule at specific sites

Biotechnology Principles And Processes NEET Mcqs

Question 68. A genetically engineered micro-organism used successfully in bioremediation of oil spills is a species of:

1. Trichodenna
2. Xanthomonas
3. Bacillus
4. Pseudomonas.

Answer: 4. Pseudomonas

Question 69. The construction of the first recombinant DNA was done by using the native plasmid of:

1. E.coli
2. Salmonella typhimurium
3. B.thuringiensis
4. Yeast
5. Agrobacterium.

Answer: 2. Salmonella typhimurium

Question 70. The basis of DNA fingerprinting is:

1. The double helix
2. Errors in the base sequence
3. Polymorphism in sequence
4. DNA replication
5. DNA coiling.

Answer: 3. Polymorphism in sequence

Question 71. The linking of antibiotic resistance gene with the plasmid vector became possible with:

1. DNA ligase
2. Exonucleases
3. Endonucleases
4. DNA polymerase.

Answer: 1. DNA ligase

Question 72. Gel electrophoresis is used for:

1. Isolation of DNA molecule
2. Cutting of DNA into fragments
3. Separation of DNA fragments according to their size
4. Construction of recombinant DNA by joining with cloning vectors.

Answer: 3. Separation of DNA fragments according to their size

Question 73. Which one of the following palindromic base

1. 5′ _______ GATATG ______ 3′
   3′ _______ CTACTA ______ 5′
2. 5′ _______ GAATTC ______ 3′
   3′ _______ CTTAAG ______ 5′
3. 5′ _______ CACGTA ______ 3′
   3′ _______ CTCAGT ______ 5′
4. 5′ _______ CGTTCG ______ 3′
   3′ _______ ATGGTA ______ 5′

Answer:

2. 5′ _______ GAATTC ______ 3′
3′ _______ CTTAAG ______ 5′

Question 74. An improved variety of transgenic basmati rice:

1. Gives a high yield and is rich in Vitamin A
2. Is completely resistant to all insect pests and diseases of paddy
3. Gives a high yield but has no characteristic aroma.
4. Does not require chemical fertilizers and growth hormones.

Answer: 1. Gives high yield and is rich in Vitamin A

Question 75. Genetic engineering has been successfully used to produce:

1. Transgenic models for studying new treatments for certain cardiac diseases
2. Transgenic cow-Rosie which produces high-fat milk for making ghee
3. Animals like bulls for farm work as they have superpower.
4. Transgenic mice for testing the safety of the polio vaccine before use in humans.

Answer: 4. Transgenic mice for testing the safety of polio vaccine before use in humans

Question 76. The genetically modified (GM) brinjal in India has been developed for:

1. Enhancing shelf life
2. Enhancing mineral content
3. Drought-resistance
4. Insect-resistance.

Answer: 4. Insect-resistance

Question 77. PCR and Restriction Fragment Length Polymorphism are the methods for:

1. Genetic transformation
2. DNA sequencing
3. genetic fingerprinting
4. Study of enzymes.

Answer: 4. Study of enzymes

Question 78. For transformation, microparticles coated with DNA are to be bombarded with gene guns made up of:

1. Platinum or Zinc
2. Silicon or Platinum
3. Gold or Tungsten
4. Silver or Platinum.

Answer: 3. Gold or Tungsten

Question 79. Which of the following is not correctly matched for the organism and its cell wall degrading enzyme?

1. Plant cells – Cellulase
2. Algae – Methylase
3. Fungi – Chitinase
4. Bacteria – Lysozyme

Answer: 2. Algae – Methylase

NEET Biology Organisms and Populations Main Branches Of Ecology

Ecology:

Science examines the interaction between an organism and its external environment.

• The word was introduced by Reiter (1865) and subsequently defined by Haeckel (1866) as the examination of reciprocal interactions between organisms and their environment.
• The term ecology originates from the Greek words oikos, meaning “place to live,” and logos, meaning “study.” E.P. Odum characterized it as the examination of the structure and function of nature.

NEET Biology Organisms And Populations Notes

Autoecology. Study of an individual organism or a particular species in relation to its environment.

Synecology. Study of groups of organisms (communities) in relation to their environment.

Conservation Ecology. It deals with the proper management of natural resources for the benefit of human beings.

Production Ecology. It deals with the gross and net production of organic matter content in different kinds of ecosystems so that proper land management may be achieved.

Ecological Energetics. It is concerned with the energy conservation and flow in the organisms within the ecosystem.

Radiation Ecology. It deals with the study of radioactive substances and radiation in the surroundings.

Space Ecology. This is concerned with a possible visit to and return from neighboring planets and its effects.

Estuarine Ecology. It deals with the study of organisms in estuarine points.

Read and Learn More NEET Biology Notes

Microbial Ecology. It is concerned with the studies of various principles that govern the distribution of microorganisms as algae, fungi, bacteria, etc. in nature.

Gynecology. Study of ecological adaptations in relation to genetic variability.

Paleoecology. Study of the relationship between organisms and the environment of the past.

Applied Ecology. Application of ecological concept for human welfare.

Silviculture. Study of maintenance and preservation of forests.

Organisms And Populations NEET Notes

System Ecology and Ecosystem Modeling. Data on ecological investigation are being computerized to formulate and describe the structure and function of ecosystems by preparing verbal, graphic, and mathematical models and equations and utilization in various ecological investigations.

Statistical Ecology. It deals with statistical studies on populations, sampling techniques, and community problems.

Pollution Ecology. It deals with the study of the effects of environmental pollutants on organisms and other objects.

Demoecology. Study of a population in relation to its environment.

Bioecology. Shelford and Clements used the term bioecology for the integrated study of plant ecology and animal ecology.

NEET Biology Organisms and Populations Level Of Organisation

Organism: Basic unit of study in ecology.

Population: Group of individuals of the same species inhabiting a given area.

Community Assemblage of different kinds of populations, living under the same set of environmental conditions interacting with each other. A biological community has a distinct species composition and structure.

Ecosystem A community integrated with its physical environment through the exchange of energy and recycling of nutrients.

Biome It is an ecosystem spread over a large area and defined by specified latitude, precipitation, temperature, flora, and fauna.

Biosphere Sum total of all biomes form a biosphere (The inhabited part of the earth is known as a biosphere.)

Landscape It is a part of the geographical region which is well-demarcated and consists of a large number of different types of ecosystems.

NEET Organisms And Populations Chapter Notes

NEET Biology Organisms and Populations Environment, Habitat, And Niche

The Environment Sum total of all biotic and abiotic factors that surround and potentially influence an organism is termed environment. It can be studied on

Large Scale Climate

Small Scale Microclimate

Organisms interact with their environment at several spatial and time scales. for example,

1. Bacteria – fraction of cm³
2. Tree-large area.

Weather: Short-term property of the atmosphere (such as temperature, pressure, humidity, rainfall, sunshine, cloud cover, and wind) at a given place and time which reflects hourly, daily, or weekly changes that constitute weather.

Weather changes with change in any of these atmospheric factors and has little impact on the flora and fauna of a place.

Climate average weather of an area is known as climate. It is affected by two factors

1. Temperature
2. Rainfall

Both these factors are determined by input of solar radiations which is turn depend on the latitude of that particular region.

NEET Biology Organisms And Populations Important Points

Climatic Zones

1. Tropical (0° – 20° latitude)
2. Sub-tropical (20° – 40° latitude)
3. Temperate (40° – 60° latitude)
4. Arctic and Antarctic (60° – 80° latitude)

Temperature decreases with an increase in latitude/altitude

Organisms And Populations NEET Notes

In Tropical Region Mountain: All 4 climatic Zones

1. Alpine
2. Temperature
3. Sub-tropical
4. Tropical

Temperature Zone Mountain: 2 climatic zones

1. Alpine
2. Temperate

Microclimate Climate conditions prevailing at a local scale or Immediate surrounding of plants and animals. for example: the interior of a forest is more humid than a nearby nonforested area.

Habitat Place occupied by an entire biological community for example: a pond, desert, river, or valley.

Microhabitat Part of habitual having a specific property for example edge of a pond, forest floor, or tree trunk.

Niche Or Ecological Niche (Grinnel) Refers to a specific place in a habitat occupied by a species where it can show all its activities and is characterized by the type of food available, amount of light available, and range of tolerance.

A habitat supports many species and has many niches but no two species can occupy the same niche.

Ecological Equivalents: Two different types of organisms which are living in different habitats but occupy the same niche for example both owls and cats feed on shrews and mice.

NEET Biology Organisms And Populations Organism And Its Environment

Ecology at the orgasmic level is also called physiological ecology because it explains how different organisms are adapted to their environment for survival and reproduction.

The climate of a particular region is affected by two factors i.e. temperature, and precipitation (rainfall and snowfall). Annual variations in the intensity and duration of temperature (seasons) and annual variations in precipitation are responsible for the formation of major biomes like desert rainforests, deciduous forests, and tundra.

• Regional and local variations within each biome form a variety of habitats (places occupied by a population or an entire biological community) of India.
• On this planet, life not only exists in favorable habitats but also in extreme and harsh habitats such as the Rajasthan desert, rain-soaked Meghalaya forests, streams, deep oceans, trenches, high mountain tops, boiling thermal springs, compost pits, permafrost polar regions and even in our intestines.

NEET Biology Organisms And Populations Important Points

The most important environmental factors that cause of physical and chemical conditions of different habitats are:

1. Temperature
2. Water
3. Light
4. Soil

Habitat includes not only abiotic (physio-chemical) components but also biotic components like pathogens, parasites, predators, and competitors of the organisms with which they interact constantly.

Over some time, organisms had through natural selection evolved adaptations for their survival and reproduction in different types of habitats.

NEET Biology Organisms and Populations Major A Biotic Factors

Temperature: It is the degree of hotness and coldness of a substance. It is the most ecologically relevant environmental factor. It is affected by altitude, latitude, topography, and Vegetation.

1. Tropical zone > 24°C Megatherm
2. Subtropical zone 17° – 24°C Mesotherm
3. Temperature 7° – 17°C Microtherm
4. Arctic/Antarctic <7° Hekistotherm

Temperature varies seasonally and decreases progressively from the equator towards the poles and from plains to the mountain top. There are however unique habitats, such as thermal springs and deep-sea hydrothermal vents where average temperature exceeds 100°C.

Temperature governs the geographical distribution of many plants and animals for example,

1. Mango trees do not and cannot grow in temperate countries like Canada and Germany.
2. Snow leopards are not found in Kerala forests.
3. Tuna fish are rarely found beyond tropical latitudes in oceans.

Temperature greatly affects living organisms because it affects the kinetics of enzymes and through it the basal metabolism, activity, and other physiological functions of the organisms.

• Organisms that can endure large fluctuations in temperature and can tolerate a wide range of temperatures are called eurythermal, for example, Artemesia, plants of temperate regions.
• Most of the organisms are restricted to a narrow range of temperatures, such organisms are called steno thermals, for example, palms (seashore), and plants in warm tropics.
• The levels of thermal tolerance of different species determine to a large extent their geographical distribution. In recent years, as the average global temperature is gradually increasing it is going to affect the distributional range of many species, particularly thermals.

Effects Of Temperature: Temperature affects – growth, metabolism, reproduction, sex ratio distribution coloration behavior, and morphology.

Water: Next to temperature, water is the most important factor influencing the life of organisms. Life is not possible without water.

Plants and animals show modifications according to the availability of water in the area and the requirements of conserving the obtained water. Plants in dry areas are called xerophytes. These plants develop modifications to increase water absorption and reduce transpiration.

Organisms And Populations NEET Notes

NEET Biology Organisms and Populations Soil Profile

It is the vertical section of the soil showing various layers or horizons. It consists of the following horizons:

1. Horizon ‘A’. It is the uppermost horizon of the soil called as topsoil. It shows maxi-mum biological activity. Due to having most of the plant’s roots, soil flora, and fauna in this layer, its thickness varies from a few centimeters to 3 meters. It is differentiated into 4-sublayers. The superficial sublayers of litter and duff are designated as Aoo and Ao. These are sometimes excluded from horizon ‘A’ and included under horizon ‘O’ of their own. Horizon A is subdivided into the following sublayers:
   • Aoo(O₁)(Litter layer). It is the uppermost sublayer containing freshly fallen undecomposed organic debris of dead leaves, bark, flowers, fruits, and animal remains.
   • Ao(O₂)(Duff layer). Below Aoo, the organic matter is found under different stages of decomposition. Small insects, bacteria, and fungi are in abundance.
   • A₁(Humus layer). It is dark and rich in organic matter which is finely divided, amorphous, dark brown, black colored, and mixed with mineral matter forming humus.
   • A₂ This region is of light color and has poor inorganic matter. Mineral matter has leached down due to heavy rains.
2. Horizon ‘B’ or Sub-soil. It is rich in mineral matter and very poor in organic matter. Biological activity is very little due to poor aeration. Roots of only large trees and shrubs reach in this region.
3. Horizon ‘C’ or Zone of regolith. It is composed of partly weathered parental rocks.
4. Horizon ‘R’. It is the lowermost layer of soil, consisting of rocks (unweathered) called Sub-Soil.

Comparison Of Soil Profile

NEET Biology Organisms And Populations Revision Notes

NEET Biology Organisms and Populations Responses To Abiotic Factors (Organisms Response)

Organisms are often found living under varied environmental conditions which will not permit all biochemical reactions and physiological functions to proceed with maximal efficiency and so cannot enhance the overall fitness of the species.

• During the course of millions of years of their existence, many species have evolved a relatively constant internal environment, despite varying external environmental conditions. This constancy may be in terms of optimal temperature and osmotic concentrations of body fluids.
• A process by which the organisms, keep the internal environment constant is called homeostasis.
• To further explain this concept, if an example is taken of a person who is able to perform best when the temperature is 25°C and wishes to maintain it so, even when it is hot or cold outside can be achieved by using an air-conditioner is summer and heater in winters.
• Then performance would be always maximal, regardless of the weather around. This homeostasis is obtained through technology. It occurs through an expenditure of external energy.
• Organisms maintain homeostasis through physiological means which requires an expenditure of internal energy of the body. However, all organisms are not able to spend so much energy on maintaining homeostasis.
• So, to meet stressful abiotic conditions organisms regulate, conform, migrate, and suspend their activities.

Regulate: Some organisms are able to maintain homeostasis by physiological means which ensures constant body temperature, constant osmotic concentration, etc. All birds and mammals, and a very few vertebrate and invertebrate species are indeed capable of such regulation (thermoregulation and osmoregulation).

• Animals having a regulated body temperature are called endothermic homoithermal or warm-blooded animals. The success of mammals is largely due to their ability to maintain a constant body temperature and because of this they thrive well whether they live in Antarctica or in the Sahara desert.
• The mechanisms used by most mammals to regulate their body temperature are similar to the ones that we humans use. We maintain a constant body temperature of 37°C. In summer, when the outside temperature is more than our body temperature, we sweat profusely.
• In winter when the temperature is much lower than 37 °C, we start to shiver, a kind of exercise which produces heat and raises the body temperature. Plants, on the other hand, do not have such mechanisms to maintain internal temperatures.

Conform: the majority of animals (99%) and nearly all plants cannot maintain a constant internal environment. They do not have a temperature-regulating mechanism. The temperature of such organisms changes with the surrounding temperature. Such animals arc called ectothermit poikilothermal or cold-blooded animals.

• In aquatic animals, the osmotic concentration of the body fluid changes with that of the ambient water osmotic concentration. Such plants and animals that change their internal environment in response to the external environment are called conformers.
• Although regulators are most benefitted hut still conformers have not evolved to become regulators. It is comparable to the situation, where a person will sweat in summer because cannot afford an air-conditioner so will continue with sub-optimal performance in the hot summer months.
• Thermoregulation is energetically expensive for many organisms. This is particularly true for small animals like shrews and hummingbirds. Heat loss or heat gain is a function of surface area.
• Since small animals have a larger surface area relative to their volume, they tend to lose body heat very fast when it is cold outside; they have to expend much energy to generate body heat through metabolism.
• This is the main reason why very small animals are rarely found in polar regions. During the course of evolution the costs and benefits of maintaining a constant internal environment the taken into consideration.
• There are some organisms that are intermediate between conformers and regulators. They are able to maintain homeostasis up to a certain limit beyond which they behave like conformers. They are known as partial regulators.
• If the stressful external conditions arc localized or remain only for a short duration, the organisms have two other alternatives.

Migrate: The organism can move away temporarily from the stressful habitat to a more hospitable area and return when the stressful period is over. Like a person moving from Delhi to Shimla for the duration of summer.

Many animals, particularly birds, during winter, undertake long-distance migrations to more hospitable areas. Every winter the famous Keoladeo National Park (Bharatpur) in Rajasthan receives thousands of migratory birds coming from Siberia and other extremely cold northern regions.

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Suspend (Stop For A Time): In bacteria, fungi, and lower plants, various kinds of thick-walled spores are formed which help them to survive unfavorable conditions and germinate only on the availability of a suitable environment.

In higher plants, seeds and some other vegetative reproductive structures serve as means to tide over periods of stress besides helping in dispersal. They do so by reducing their metabolic activity and going into a state of dormancy. In animals, the organism, if unable to migrate, might avoid the stress by escaping in time. It is of three types :

• Hibernation i.e. winder sleep for example Bears.
• Aestivation i.e. summer sleep for example Some snails and fish.
• Diapause: Under unfavorable conditions, many zooplankton in lakes and ponds are known to enter diapause a stage of suspended development. Diapause is a stage in the development of certain animals during which developmental growth is suspended during winter when days are short.

Organisms And Populations NEET Chapter Summary

NEET Biology Organisms and Populations Ecological Levels Of Organisation

The ecological levels of the organization are an organism, population, community, ecosystem, biome, and biosphere.

• Organisms are the basic unit of study in ecology. At the organismic level, we intend to study form, physiology and behavior, distribution, and adaptations in relation to environmental conditions.
• Species is a group of organisms interbreeding among themselves to produce fertile young ones of their own kind.
• Population Level. Individuals of a species living in an area form a freely interbreeding group called a population, for example, all individuals of elephants living in an area constitute a population.
• Community Level. Populations of different species present in an area develop interdependence and interactions to form a well-knit group called a community or biotic community.
• Ecosystem Level. The biotic community of a segment of nature interacts with abiotic factors to form an ecosystem. An ecosystem is generally a self-sufficient unit that has its own flow of energy, biogeochemical cycles, and system of controls.
• A landscape is a unit of land with a natural boundary having a mosaic of patches.
• Biome Level. A number of ecosystems are associated with forming a bigger organization specific to a geographic area or climate. It is called a biome. Some examples of biomes are deserts, temperate deciduous forests, tropical rainforests, etc.
• Environment is sum total of all biotic and abiotic components.
• The short-term properties of the atmosphere such as temperature, pressure, humidity, rainfall, sunshine, cloud cover, and wind at a given place and time are termed weather.
• Climate. It is the average weather of an area.
• Biosphere. It is the largest biological system on a global scale which occurs in the whole living mantle of the earth. The biosphere has the highest level of organization. It is made of several biomes.
• The different climatic regions are tropical, subtropical, temperate arctic, and antarctic.
• Habitat is the natural place of living of an organism.

Differences Between Habitat And Environment

Differences Between Habitat And Microhabitat

Microclimate. It represents the climatic conditions that prevail at a local scale, or in areas of limited size such as the immediate surroundings of plants and animals. Microclimate generally differs from the prevailing regional climatic conditions. For example, in a forest, dense foliage reduces the amount of light reaching the ground.

This also results in a changed air temperature profile. The daytime air temperature inside the forests is lower than outside. Also, the interior of a forest may be more humid than a nearby non-forested area.

Organisms And Populations NEET Chapter Summary

NEET Biology Organisms and Populations Ecological Niche

The ecological Niche of an organism represents the range of conditions that it can tolerate, the resources it utilizes, and its functional role in the ecological system. The ecological niche involves not only the physical space occupied by an organism, but also its functional role in the community (i.e., a trophic position occupied), and its position in environmental gradients including other conditions of existence. The term ‘niche’ was for the first time used by Grinncl. (1971)

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Kinds Of Ecological Niche

1. Trophic Niche. It is associated with the trophic position of an organism. For example. the two aquatic bugs. Corixa and Nototiccta live in the same habitat, i.e., pond but occupy different trophic niches.
2. Spatial Or Habitat Niche. It is concerned with the physical space occupied by an organism. The best example of spatial or habitat niche is provided by the distribution of seven species of millipedes in the forest floor of a maple-oak forest (O’Neill, 1967).
   • All seven species occur in the same general habitat, i.e., forest floor, and belong to the same trophic level (that is all are decomposers in their role as detrivores). Another example is provided by the three species of fungi colonizing the decaying culms of fodder grass, for example, Setaria glauca.
   • These all fungi live in the habitat, the decaying internodes. and they all belong to the same trophic level (decomposers).
3. Multifactor Or Hypervolume Niche. Multifactor (hypervolume) niche concept was developed by G.E. Hutchinson (1965) of Yale University. He suggested that if we measure the range of some environmental variable (for example, temperature) over which a particular species can live and reproduce we put this on a graph.

We then do the same for another environmental variable (for example, humidity) and put this on the second axis of the graph. The space that is enclosed will represent the niche of the species.

Since there are a large number (n) of other environmental factors, both abiotic and biotic, that affect the population, the niche is n-dimensional hypervolume, an abstraction since we are able to draw only with respect to three dimensions. This is considered to be the fundamental niche of the species.

Organisms And Populations Class 12 Notes For NEET

NEET Biology Organisms And Populations Environmental Factors And Their Importance To Plants And Animals

Environmental Factors Include:

1. Light
2. Temperature
3. Humidity
4. Wind
5. Rainfall
6. Water
7. Atmospheric gases.

1. Importance Of Light. It is important for photosynthesis, flowering in plants, bird migration, reproductive activities, biological rhythms, plant growth, metabolism, and periodicity.
2. Effect Of Temperature. It is the most important factor affecting almost all activities of organisms. Most organisms can survive in the temperature range of 5°-35° C (except certain bacteria) cyanobacteria, shelled protozoa.
3. Importance Of Humidity. It is the number of water vapors present in the atmosphere. Absolute humidity is maximum near the equator and gradually decreases towards the poles. It plays an important role in the life of plants as well as animals.
   • It promotes the growth of epiphytes example, orchids, and other plants that support animal life.
   • It regulates the evaporation of water from the body of land organisms in transpiration and perspiration.
4. Importance Of Wind. Air in motion is called wind. Its direct effects are physical or mechanical while indirect effects are physiological. Wind modifies the humidity. Dry winds diffuse the dwarfing of plants. Wind helps in pollination, and dispersal of fruits and seeds and prevents frost damage.
   • Sometimes shrubs and trees are planted to protect the field against wind. Such structures are known as windbreaks or shelter belts. These plants (trees) are planted at 90° to the wind velocity.
   • It affects both plants and animals (more effects on plants) in the following ways :
     • Strong winds cause soil erosion reducing soil fertility. These also cause desertification by shifting of sand particles to fertile areas.
     • These cause lodging (flattening of plants against the ground) of plants like wheat, rice, maize, oats, sugarcane, etc.
     • These increase the rates of evaporation and transpiration leading to desiccation which causes dwarfism in the plants.
5. Importance Of Rainfall. Rainfall is the source of groundwater and relative humidity (the ratio of the pressure of water vapors in the air to the vapor pressure of the air when saturated with water vapors at the same temperature). The amount of annual rainfall greatly affects the vegetation as well as the animal population of a particular region.
6. Importance Of Water. Water is essential for life. It covers more than 70% of the earth’s surface and forms the most extensive habitat for the organisms. Types of plants and animals distributed in water bodies greatly depend upon the nature of water (freshwater or seawater). Land plants derive water from the soil while land animals derive water from pools, ponds, lakes, rivers, springs, etc.

NEET Biology Organisms and Populations Tolerance Factors Determine Distribution Of Species

Range Of Tolerance:

• Biological species exhibit varying degrees of tolerance to environmental variables.
• These components exhibit variability in their impact, and anyone present in minimal quantity may constitute a limiting factor.
• The reaction of an organism to varying gradients of a singular environmental element, such as temperature, sunlight, or nutrient concentration, produces a bell-shaped curve as illustrated.

Different Layers Of Atmosphere

Organisms And Populations Class 12 Notes For NEET

NEET Biology Organisms and Populations Zones In The Lake

Shelford proposed the law of tolerance which states that organisms show all grades of tolerance and may have a wide range of tolerance of one factor and a very narrow range for another. Some additional principles of the law of tolerance may be stated as follows:

1. Organisms may have a wide range of tolerance for one factor and a narrow range for another.
2. Organisms with a wide range of tolerance for all the factors are likely to be most widely distributed.
3. When conditions are not optimum for a species with respect to a particular environmental factor, the limits of tolerance may be reduced with respect to other factors.
4. The limits of tolerance for reproductive individuals, seeds, eggs, embryos, and larvae are usually narrower than for non-reproductive adult plants or animals. For example, adult blue crabs and many other marine animals can tolerate brackish water or fresh water with a high chloride content, but their larvae cannot live in such water and hence, they cannot reproduce in rivers and are not established there permanently.

To describe a species with a narrow range of tolerance for a particular factor, we use the prefix sten., for those with a wide range, we use the prefix eury. The term steno¬thermal and eurythermal, refer to temperature tolerance.

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Liebig’s Law of Minimum. This law states that the growth of the plant is dependent on the amount of the foodstuff which is to it in minimum quantity.

• This statement is later on combined with a law of limiting factors first proposed by the British physiologist.
• Blackmann who investigated the factors affecting the rate of photosynthesis and found that the rate is governed by the level of the one factor operating at a limiting intensity.
• The two concepts combined form the so-called Liebig-Blackmann law.
• However, two additional principles must be added.
• The first is a constraint that Liebig’s law is strictly applicable only under steady-state conditions, i.e., when the inflow of energy and materials balances the outflow.
• The second important consideration is the factor interaction. Thus, a high concentration of some substance, or the action of some factor other than the minimum one, may modify the rate of utilization of the latter. In other words, a high level of one factor or substance will modify the limiting effect of another, a process known as factor interaction.

Organisms And Populations Class 12 Notes For NEET

NEET Biology Organisms and Populations Species And Population

The individual is the most concrete entity with a distinct structure and definite function.

• Individual organisms of the same kind form higher units such as family, herd, population, and species.
• Out of the above list, the species and population are the most universal and stable units.
• Species include closely related, morphologically similar individuals who interbreed among themselves to produce the fertile young ones of their own type. Members of species may show individual variation, and sexual dimorphism and may occur as varieties. Polymorphic species have many specialized morphic forms which perform certain functions.
• Different species may be bred artificially, but do not interbreed freely in nature.
• New species evolve from pre-existing species by modifications.
• All species show various cooperative and competitive interactions among their members.
• Many species of animals have a definite home range in which their members find food and mates. Different groups form their territories which are often marked and guided by their members.
  a Members of species show intraspecific competition for food, territory, rank, and mate. Cooperation and sexual reproduction are the most fundamental and universal interactions.
• Demography is the branch of the study of different aspects of the human population.

A population is a group of organisms of the same species living in a definite area at a given time.

Human Racers

• Negroids
  • Dark skin
  • Warty Hair
  • Thick lips
• Caucasoids
  • Light to dark skin
  • Blue to dark-eye
  • Medium to thin
  • Abundant body
• Mongoloid
  • Yellow to brown skin
  • Brown eye
  • Medium to thin lips
  • Few body hairs

A set of local populations connected by dispersing individuals is called metapopulation,

• Population has group characteristics, like density, natality, mortality, dispersal, distribution, biotic potential, and growth forms,
• Population density is determined by the total number of individuals per unit space at a specific given time.
• The size of the population is also affected by the natality (birth) and mortality (death) rate. It is also regulated by food, space, disease, and other natural factors, Human populations are characterized by rapid growth, wide distribution, and perennial reproductive activity.
• Socio-cultural factors determine the human populations.
• The inherent maximum capacity of an organism to reproduce or increase in number is termed biotic potential (r).
• The environmental check on population size or its biotic potential is called environmental resistance (k).
• The growth of population can be measured as an increase in its size over a period of time.
• An S-shaped growth curve is obtained for most of populations,
• No single population can live in isolation in a natural environment,
• A biotic community is an association of several populations belonging to different species living in a common environment and interacting with one another,
• The various species in a community share a common environment and are related by direct or indirect interactions.

Organisms And Populations Class 12 Notes For NEET

NEET Biology Organisms and Populations Biotic Community

A population of a single species is not a viable entity or unit by itself. An association of a number of different species in a common environment that can survive in nature is called
biotic communities such as pond communities, forest communities, etc.

Biotic Isolation. The occurrence of organisms living in isolation from other organisms.

Biotic Stability. Tendency in which a biotic community becomes stable.

• It depends upon species diversity; the presence of biological contest, population density, and the carrying capacity of the environment. The larger the number of species present in a biotic community, the more stable it is.
• The relationship between one species and another within a community has evolved through their interactions, based on the requirement and mode of obtaining food and shelter and also on the habits of the species.

Characters In Community Analysis

1. Species composition
2. Dominance
3. Physiognomy and stratification.
4. Species diversity
5. Keystone and link species.
6. Ecotones and Edge effect.

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Earth’s Vegetation Can Be Divided Into Different Zones Based On Altitude.

1. Upto 1800 feet—Tropical rain forest.
   • Tropical moist deciduous with 1000-1500 mm rainfall
   • Tropical moist evergreen with 2500 mm rainfall.
2. 18001—4000 feet—Grassland or desert, savannah
3. 4000’—7500 feet—Temperate deciduous forest. Oak is common
4. 7500—12000 feet— Coniferous forest (Temperate evergreen forests) for example Pinus, Abies, Picea.
   • 12000 feet is regarded as a tree or timberline. Above this height of plants decreases.
5. 12500—14500 feet— Alpine vegetation (tundras)

NEET Biology Organisms and Populations Biotic Stability

A biotic community is formed of large numbers and very diverse types of populations of plants, animals, and microbes which differ taxonomically from each other. All these populations are essential for biotic stability

Biotic Stability Definition: Absence of major fluctuations in the population and ability to undergo homeostasis after a disturbance). So stability amongst diversity is an important feature of a biotic community.

Elton (1958) stated that the stability of a biotic community is mainly governed by the number of species in it and the interactions between them. The larger the number of species in a community, the more stable it will be because:

1. These provide alternative sources of food.
2. Proper dispersal of different species so decreases the spreading of epidemics.
3. Adjustment between members of different species using the same resource.
4. Reduction of intraspecific interactions.
5. Presence of biological control.

A monoculture community (having a population of single plant species) for example Eucalyptus or Casuarina acts as a paradise for pests and pathogens so is likely to be wiped out by fungal diseases or pests.

But in a polyculture community (having many populations of different plant species), only one species may be affected by a disease whereas the rest would survive. So a polyculture Tropical rain forest biome is more stable than a Tundra biome.

Organisms And Populations Class 12 Notes For NEET

Behavioral Strategies Of Adaptations In Animals

NEET Biology Organisms and Populations Migration

Migration involves long-distance or short-distance movement of animals from one place to another. Many organisms that fly or swim undertake extensive migration as depicted below:

Migration As A Strategy Of Adaption In Animals

NEET Biology Organisms and Populations Ecads

Ecads are alternatively known as ecophenes. An ecad of a plant species is a group of individuals that, while sharing the same genetic lineage, display notable variations in vegetative traits, such as leaf count on the stem, morphology, and dimensions.

• These differences are solely environmental and thus transient or reversible. A shift from one ecad variety to another may occur due to a change in habitat.
• Thus, the appearance of all ecads would be analogous if they were relocated to the same habitat.
• A multitude of ecads has been recorded across several species. Ramakrishnan (1960) noted that Euphorbia hirta, belonging to the  Euphorbiaceae family, exhibits two ecads in India:
• One that thrives in arid, compact soil (prostrate type) and another that flourishes along footpaths subjected to trampling (prostrate compact type).

NEET Biology Organisms and Populations Aquatic Thermal Zonatiqn

Based on temperature, as many as three aquatic strata have been differentiated where the temperature ranges between 5° to 23° C. This stratification becomes distinct in lakes during summer.

Epilimnion. It is the uppermost zone where the temperature decreases gradually.

Thermocline Or Metalimnion. It is the middle short zone where the temperature falls rapidly.

Hypolimnion. It is the lowermost or the bottom zone where the temperature gradients are not distinct. Its temperature may go up to 5° C.

Nocturnal. Active at night (moths, owls, bats, cockroaches).

Diurnal. Active during the day (butterflies, sparrows, crows, pigeons).

Auroral. Active at dawn only.

Vespernl. Active at dusk only. (Rabbit)

Adaptations In Organisms NEET Study Material

Crepuscular. Active at dawn and dusk (Rabbit).

• Long Day Plants Raddish, spinach
• Short Day Plants: Xanlhium, dahlia
• Day Neutral Plants: Tomato
• Desiccation: Transpiration rate exceeds absorption.
• Pyric Factor: It refers to fire.
• Lentic: Pertaining to standing water.
• Lotic: Pertaining to flowing water.

Organisms And Populations Class 12 Notes For NEET

NEET Biology Organisms and Populations Hydrologic Adaptation

On the basis of water requirement and the type of soil, Warming, (1909) differentiated three major and thirteen minor types of plant communities as under:

1. Hydrophilous:
   • Hydrophytes: Plants living in water,
   • Helophytes: Plants living in marsh,
2. Xerophilous:
   • Oxylophytes: Plants growing on acidic soil,
   • Lithophytes: Plants growing on rocks,
   • Halophytes: Plants growing on saline soil,
   • Psammophytcs: Plants growing on sand and gravel,
   • Chersophytes: Plants growing on wastelands,
   • Psyehrophytes: Plants growing on cold soil,
   • Eremophytes: Plants growing in desert and steppe,
   • Psilophytes: Plants growing in savannah.
   • Sclerophyllous Formations: Include forests of shrubs and trees having sclerenchyma in the leaves.
   • Coniferous Formations: Include forests of conifers.
3. Mesophilous:
   • Mesophytes: Terrestrial plants growing in normal habitat.

NEET Biology Organisms and Populations Adaptations Of Different Kinds

The ecological adaptation of the three major groups i.e., hydrophytes, mesophytes, and xerophytes shall now be dealt in some detail are as follows.

Hydrophytes: The hydrophytes are generally classified into the following five categories

1. Free Floating: for example Lemna, Wolffia, Spirodela, Pistia, Eichhomia etc.
2. Submerged Floating: for example Utricularia, Ceratophyllum, Najas etc.
3. Rooted Submerged: for example Hydrilla, Vallisneria, Potamogeton etc.
4. Rooted With Floating Leaves: for example Nymphaea, Victoria, Trapa, etc.
5. Rooted Emergents: for example Ranunculus, Sagittaria etc.

Hydrophytes Morphological Adaptation

1. Roots absent (Ceratophyllum, Wolffia ) or poorly developed.
2. Root hair is absent in floating forms or poorly developed.
3. Root cap absent, root pockets may be present (Eichhomia, Pistia).
4. In some forms (Utricularia, Jussiea) floats may be present.
5. In a few forms rhizomes (Nymphaea, Nelumbo) or stolons (Pistia, Eichhomia) may be present.
6. Stems may be long, thin, slender, and elastic (Hydrilla).
7. Leaves may be dissected (Uricularia, Ceratophyllum) or ribbon-shaped (Vallisneria).
8. Leaves sometimes with bulbous/swollen base (Eichhomia, Trapa).
9. Heterophylly present in emergent forms (Ranunculus, Sagittaria).

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Mesophytes: The mesophytes can be classified into two community groups as under

1. Herbaceous communities,
2. Communities of woody plants.

The former communities are represented by herbaceous flora which is distinguishable into arctic and alpine grasslands, meadows and pastures, and croplands. The communities of woody plants comprise mesophytic bushlands, deciduous forests, and evergreen forests. The evergreen forests include antarctic forests, sub-tropical forests, and tropical rainforests.

The Mesophytes Are Characterized By:

1. Root system well developed with distinct root cap and root hair.
2. The shoot system is well organized; stems are generally aerial, sometimes underground or sub-aerial.

Xerophytes: The xerophytes are generally described as‘ plants of dry habitat’. They are generally classified into the following three categories

1. Ephemeral Annuals. These plants escape dryness externally as well as internally. Hence they are also called ‘Draught resistant’. Argemone indica. Solariumxanthocarpum etc.
2. Succulents. They suffer dryness externally but escape internally due to the presence of fleshy water storage tissue for example Opuntia, Aloe, Agave, Euphorbia sp.
   • Succulent Xerophytic Plants Are Of the Following Types:
     1. Chylocaulous stores the water in their succulent stem for example Opuntia, Euphorbia, etc.
     2. Chylophyllous stores the water in their leaves for example Agave, Aloe, Tradescantia, etc.
     3. Chylorhizous stores the water in their roots for example Asparagus.
3. Non-succulent. They escape dryness externally as well as internally. They are the true xerophytes, for example, Calotropis procera, Casurina, Acacia nelotica, Zizyphus jitjuba, Capparis apliylla, etc.

On the basis of leaves, the xerophytes are sometimes classified into four groups.

1. Microphyllous. They have leaves with very much reduced surface.
2. Malacophyllous. They have fleshy leaves.
3. Trichophyllous. They have hair on the leaf surface.
4. Sclerophyllous. They have sclerenchyma inside the leaves.

Organisms And Populations Class 12 Notes For NEET

Xerophytes Morphological Adaptations

1. The root system is very well developed, even longer than the shoot.
2. Root cap present, root hair extensively developed,
3. Stems short, dry, hard, and rough.
4. Presence of thick bark.
5. Often phylloclades and cladodes are present.
6. Leaves may be absent or reduced to spines or scales.
7. Leaves usually with reduced surface.
8. Stipules are spiny in many species (Acacia, Capparis, Zizyphus).
9. Rarely phyllodes are present.
10. Leaf surface shiny or hairy.
11. Rolling of leaves in some plants.

Halophytes: Plants growing on saline soil are called as halophytes. On the basis of salt contents, they have been divided into three categories by Inveron, 1936 as under

1. Oligohalophytes. They grow where NaCI concentration ranges between 0.01 to 0.1%,
2. Mesohalophytes. They grow where NaCI concentration ranges between 0.1% to 1.0%
3. Euhalophytes. They grow where NaCI concentration is 1.0% or more.

The Angiospermic Coastal Halophytes Are Of Two Types;

1. Hydrohalophytes. They remain in the water.
2. Hygrohalophytes. They are low coastal types.
   • Swamp halophytes
   • Marsh halophytes

The Halophytes Are Classified As Under.

1. Lithophilous. They grow on rocks.
2. Pssamophilous. They grow on sand.
3. Psilophilous. They grow in savannah.
4. Halophilous. They occur in saline soil.

Halophytes Adaptations

1. Presence of shallow root.
2. Presence of necrotrophic roots.
3. Root buttresses-shaped.
4. Leaves thick, succulent.
5. Show viviparous germination.
6. Presence of thick cuticle.
7. Root cover of star-shaped cells.
8. Thick-walled hypodermis.
9. Aerenchyma present.
10. Sclereids and H-shaped spicules are present.
11. Vascular tissue is well developed.
12. Multilayered cork in roots.
13. Leaves generally hypostomatic
14. Mesophyll is well differentiated.
15. Water-storing tissue extensively developed.
16. Presence of sunken stomata.
17. Possess low chlorophyll contents.
18. Show a high rate of transpiration.

Some of the common halophytes are Spertina altemilora, Aegiceras majus, Avicennia, officinalis, Rhizophora mucronata etc.

Cryptophytes (Geophytes ). Plants grow below the soil with underground buds such as bulbs and rhizomes. They are found in arid zones.

Hemicryptophytes. Perennial plants with buds in or just below the soil surface. Examples. Most of the biennial and perennial herbs.

Chasmophytes. Plants growing in rock crevices.

Calciphvtes. Plants usually grow in soil rich in calcium for example Euphorbia, and Lindernbergia.

Adaptations In Organisms NEET Study Material

Chamaeophytes. Surface plants with prostrate habitats have buds on the surface of the ground.

Annual Ephemerals. Plants that are capable of withstanding adverse conditions in the form of seeds.

Cryophytes. Plants growing on ice: Rhododendron, Betula. (Cushion-shaped dwarf shrubby vegetation)14500 feet up-ward—Snow line.

Organisms And Populations Class 12 Notes For NEET

Types Of Vegetation On The Basis Of Rainfall

1. Forests. Moderate to heavy rainfall occurring throughout the year in warm tropics produces evergreen rainforests. Heavy rainfall occurs in 7-8 months a year and produces deciduous forests. Areas having little summer but sufficient winter rainfall produce only scrub forests.
2. Grassland. The places receiving high summer rainfall and low winter rainfall develop grasslands, which may be of two types.:
   • Prairie. A tract of grassland without any trees is called a prairie.
   • Savannah. A grassland with scattered trees is called a savannah.
3. Desert. Deserts develop in places having very low summer and winter rains.

NEET Biology Organisms and Populations Biological Rhythms Are Of 3 Types

Circadian Rhythms for example opening and closing of stomata, nyctinastic movements, etc.

Tidal/Lunar Rhythms are associated with some particular moon phase for example, Spawning in Nereis, a menstrual cycle of 28 days in the human female.

Annual/Seasonal Rhythms are associated with some specific season of the year for example, hibernation in winter, aestivation in summer, shedding of leaves, flowering, etc.

NEET Biology Organisms and Populations

Biotic Community: It is a grouping of different but interdependent and interacting populations of different species that live together in a given locality. For example, pond community forest community

Population: In ecology, it is a group of individuals of the same species inhabiting the same area and functioning as a unit of a biotic community. or

• It is a unit of a biotic community made up of a near-permanent group of interbreeding individuals of a species found in a particular area at a given time.
• Although the term interbreeding is applied for sexual reproduction, a group of individuals produced from even asexual reproduction is also considered as population, for example, all the cormorants in wetlands, all rats in an abandoned dwelling, teakwood trees in a forest tract, bacteria in a culture plate and lotus in a pond.
• Natural selection operates at the population level to evolve the desired traits, although, it is the individual organism, who has to cope with the changed environment.
• A population has certain qualities that an individual organism does not have. For example, individuals may have deaths and births but the population has birth rates and death rates.
• Population ecology is, therefore, an important area of ecology, because it links ecology to population genetics and evolution.

Important Characteristics/ Attributes Of A Population Are

1. Birth Rate (Natality): It is expressed as an increase in a number of births with respect to a number of individuals in a population. for example, If in a pond there were 20 lotus plants last year and through reproduction 8 plants are added so the current population is 28 then the birth rate is 8/20 = 0.4 offspring per lotus per year.
2. Death Rate (Mortality): It is expressed as a decrease in the number of deaths with respect to the total number of individuals in the population. for example, If 4 individuals in a laboratory population of 40 fruit flies died during a specified time interval (say a week) then the death rate in the population during that period is 4/40 = 0.1 individual per fruit fly per week.
3. Sex Ratio: An individual has sex (male or female) but a population has sex ratio (for example 60% of the population are females and 40% males).
4. Age Distribution: Various groups in the population determine its reproductive status.
   • Three ages are referred to as ecological ages
     • Pre-reproductive
     • Reproductive
     • Post-reproductive
5. Age Pyramids: A graphic representation of different age groups found in a population with pre-productive groups at the base, reproductive ones in the middle, and post-reproductive groups at the top is called age pyramid. Depending upon the proportion of age groups we have three types of population and pyramids.
   • Growing/Expanding Population (Triangular Age Pyramid): When a number of pre-reproductive individuals form the largest group. It shows positive growth.
   • Stable Population (Bell-shaped Age Pyramid): When a number of pre-reproductive individuals in almost equal to reproductive individuals. Population growth is zero.
   • Declining Population (Urn-Shaped Age Pyramid): When a number of reproductive individuals is more than the number of pre-reproductive individuals. A number of post-reproductive individuals are also sizeable. It shows negative growth.
6. Carrying Capacity (K): The maximum number of individuals of a population that can be sustained indefinitely in a given habitat, represents its carrying capacity. At K, the growth rate is equal to zero, Beyond K, population size decreases.
7. Biotic Potential Vs Environment Resistance: An environmental check on population size or its biotic potential, is called environment resistance. Environmental resistance represents the limiting effect of abiotic (i.e. H₂O and space) and biotic factors (i.e. food and competition) that do not allow the organization to attain its biotic potential and keep the population size at a much lower level.
   • Environmental resistance = \(\frac{K – N}{K}\).
8. Population Size: The size of the population is dependent upon the outcome of competition with another species, the impact of the predator, or the effect of the use of pesticides.
   • Population size also called population density, (designated as N) is generally measured in numbers or in percent cover or biomass, per unit area for example with respect to number it can be as low as 10 (Siberian cranes at Bharatpur wetlands in any year) or go into millions (Chlamydomonas in a pond).
   • Although the total number is the most appropriate measure of population density, in some cases, it may not depict the correct role of a species in a large community. for example in a forest area, if there are 200 Parthenium plants and only one Banyan tree with a large canopy, we cannot say the population density of Banyan is low.
   • In such cases, percent cover or biomass is taken as a measure of population size.
   • If the population is large and counting is not possible, then relative densities are taken into consideration.
   • for example number of fish caught per trap is a good enough measure of the total population density in the lake.
   • Sometimes population size is indirectly estimated without actually counting them.
   • The Tiger census in National Parks and tiger reserves is often based on pug marks and fecal pellets.

Organisms And Populations Class 12 Notes For NEET

Adaptations In Organisms NEET Study Material

Population Growth: The size of a population for any species keeps changing in time, depending on various factors including food availability, predation pressure, and changing weather conditions.

These changes in the population density give some idea of whether it is flourishing or declining. The density of a population in a given habitat during a given period fluctuates due to changes in four basic processes, two of which (natality and immigration) contribute an increase in population density and two (mortality and emigration) to a decrease.

1. Natality: Refers to the number of births during a given period in the population that are added to the initial density.
2. Mortality is the number of deaths in the population during a given period.
3. Immigration is the number of individuals of the same species that have come into the habitat from elsewhere during the time period under consideration.
4. Emigration is the number of individuals in the population who left the habitat and went elsewhere during the time period under consideration.

So, if N is the population density at time t, then its density at time t + 1 is N_t+1 = N_t+ [(B + 1)-(D + E)]

Under normal conditions, birth and death are the most important factors influencing population density, the other two factors, assuming importance only under special conditions, for example, if a new habitat is just being colonized, immigration may contribute more significantly to population growth than birth rates.

Growth Models: The growth of a population with time shows specific patterns resulting in different types of growth forms. These are

1. Exponetial Growth/J-growth Form: When food and space for a population are unlimited, each species has the ability to realize fully its inherited potential to grow, as Darwin observed while developing his theory of natural selection. Then the population grows in an exponential or geometric ratio.

If in a population of size N, the birth rates (not total number but per capita births) are represented as b and death rates (per capita death rates) and d, the increase or decrease in N during a unit period t(dN/dt) will be dN/dt = (b-d)xN

Let (b-d) = r, the n dN/Dt = rN

The r in this equation is called the intrinsic rate of natural increase and is a very important parameter selected for assessing the impacts of any biotic or abiotic factor on population growth. example, for the Norway rat the r is 0.015, and for the flour beetle is 0.12.

In 1981 the r value for the human population in India was 0.0205.

The above equation describes the exponential or geometric growth pattern of a population and results in a J-shaped curve when we plot N in relation to time.

We can derive the integral form of the exponential growth equation as N_t = N₀ e^rt

Where,

N_t = population density after time t

N₀ = population density at time zero

r = intrinsic rate of natural increase

e = the base of natural logarithms (2.71828)

Population Growth Models NEET Exam Preparation

Any species growing exponentially under unlimited resource conditions can reach enormous population densities in a short time. Darwin showed how even a slow-growing in animal like an elephant could reach enormous numbers in the absence of checks.

2. Logistic Growth, S-Shaped, Or Sigmoid Growth Form: In nature, populations do not have unlimited resources at their disposal. This leads to competition between individuals for limited resources. So in nature, exponential growth usually is not common.

• Many countries have realized this fact and introduced various restraints to limit human population growth. In nature, a given habitat has enough resources to support the maximum possible number, beyond which no further growth is possible.
• This limit is called as nature’s carrying capacity (K) for that species in that habitat. A population growing in a habitat with limited resources shows initially a lag phase, followed by a phase of increase (log phase) and decrease (declining phase), and finally, the population density reaches the carrying capacity (Stationary phase, Asymptote).
• A graph of N in relation to time (t) results in a sigmoid curve.

This type of population growth is called Verhulst-Pearl Logistic Growth as explained by the following equation

dN/dt = rN (\(\frac{K-N}{K}\))

where N = Population density at time t

r = intrinsic rate of natural increase

K = Carrying capacity

Since resources for growth for most animal populations become limited sooner or later, the logistic growth model is considered a more realistic one.

Life history Variation: Populations evolve to maximize their Darwinian fitness (high r-value) in their habitat. It is known that in nature

1. Some species live very long (for example, humans) some only for a short time (for example insects),
2. Some breed only once in their lifetime (for example pacific salmon fish, bamboo) while others breed many times during their lifetime (for example, most birds and mammals,
3. Some produce a large number of small-sized offspring (for example, oysters, and pelagic fishes) while others produce a small number of large-sized offspring (for example birds, and mammals).
4. Ecologists suggest that life history traits of organisms have evolved due to the restrictions imposed by the abiotic and biotic components of their habitat.

Population Interactions: In nature animals, plants, and microbes cannot live in isolation, but interact in various ways to form a biological community. Three types of factors govern the ecological interaction amongst different populations of a biotic community i.e.

1. Requirement and mode of obtaining food.
2. Type and area of shelter.
3. Habits of different populations.

Interspecific interactions arise from the interactions of populations of two different species.

These could be

1. Beneficial (+ ve)
2. Detrimental (-ve)
3. Neutral (0)

All types of interactions have been called symbiosis by DeBary. (Later on, the term symbiosis became synonymous with mutualism).

Organisms And Populations Class 12 Notes For NEET

NEET Biology Organisms and Populations Interaction

Positive Interaction. Commensalism, proto-co-operation, and mutualism arc the interaction between two different species and limit the growth and distribution.

Negative Interaction. Amensalism, parasitism, predation, and competition are the negative interactions that govern the growth and distribution.

Neutral Interaction. In which neither of the two species is benefited nor harmed. According to Me Dougal symbiosis when conjunctive type (permanent) may be social or nutritive. When it is of disjunctive type (non-permanent) also it may be social or nutritive, The nutritive type may be antagonistic or reciprocal.

Clark differentiates symbiosis and antagonism as two distinct types of relationship. Burk Holder, however, differentiates at least nine types of relationships such as neutralism, competition (direct interference/resource use types), amensalism, parasitism, predation, commensalism, protocol operation, and mutualism.

NEET Biology Organisms and Populations Predation

It is a direct biological relationship between two species wherein one species (the predator) lethally consumes the other species (the prey) for sustenance. Consequently, a predator-prey dynamic exists.

• Insectivorous plants, including Drosera, Utricularia, Dionaea,
• Aldrovanda, Pinguicula, Nepenthes, Sarracenia, Cephalotus,
• Darlingtonia, and Heliamphora, exemplify predation effectively. These plants consume insects and microorganisms to address their nitrogen shortage.
• Herbivores consume not only herbs but also shrubs and trees. The plants are adversely affected to varying extents by grazing and browsing.
• Annuals endure more intensive grazing compared to perennials.
• Selective grazing results in an increase in the prevalence of unpleasant, thorny, and shrubby plants.
• Consequently, biodiversity is diminished. This also diminishes the humus content of the soil.
• Nevertheless, grazing and browsing contribute to a notable rise in soil nitrogen levels through the deposition of excreta from grazing animals. A frog functions as both a predator and prey.

Population Growth Models NEET Exam Preparation

Interactions Amongst Different Species

NEET Biology Organisms and Populations Scavenging

Is also a direct relationship where an animal feeds on another dead animal that has died naturally or has been killed by another animal.

NEET Biology Organisms and Populations Parasitism

It is a relationship between two species in which one (parasite) is nearly dependent on the other (host) and may cause disease.

Characters Of Parasites

1. Small size population.
2. They are host-specific.
3. they have higher biotic potential.
4. They have poor means of dispersal and require special structures to reach or invade the host.
5. They alter the population growth of the host.
6. They cause weakness in the host.

The gainer is called a parasite and the loser is the host. The host is always larger than the parasite. On the basis of the position of the host, the parasites are classified into two categories ectoparasite and endoparasite. The endoparasite lives inside the host whereas the ectoparasite lives on the surface.

• The parasitism may be total or partial. The former remains a parasite throughout its life and is wholly dependent whereas the latter is only partly dependent upon the host showing a tendency towards free living. On the basis of their location on a specific body part, the parasites have been categorized as stem, root, or leaf parasites.
• The plants of Cuscula are total stem parasites whereas those of Orobanche, Rafflesia, Balanopliora, etc. are total root parasites. The partial stem parasites are Dendrophoe, and Viscum whereas Santalum and Thesiiun are partial root parasites.

Numerous fungi (Albugo, Puccinia, Ustilago, etc.), bacteria (Xanthomonas, Pseudomonas, Mycobacterium, Vibrio, Leptospira, etc.), and viruses are parasites on plants and animals. In the same way, several protozoans (Plasmodium, Entamoeba, etc.), flatworms, tapeworms, and roundworms live as endoparasites on other animals. A few insects occur as ectoparasites on other animals. Besides, these ectoparasites may carry fungi or bacteria as hyperparasites.

• Parasite. An organism that lives in or on another organism of different species from which it derives its nutrition.
• Parasitism. It is an association between two species where one is benefited and the other is harmed.
• Sometimes a parasite is further parasitized by another parasite and the phenomenon is called hyperparasitism for example Nosema notabilis (a sporozoan) is an obligatory parasite of Sphaerospora polymorph (a protozoan) which in turn is a parasite of the urinary bladder of toadfish.
• Social Parasitism is another interesting kind of parasitism in which one species is exploited by another species for some benefit for example cuckoo lays its eggs in the nest of a crow, leaving the eggs and the young in the care of foster parents. About 1% of all birds are brood parasites.
• Sexual Parasitism. In Photocorynus (Angler fish) male lives as a tiny permanent parasite on the head of the female and depends upon her blood supply.
• Parasitology. Study of parasites.
• The Rufus woodpecker, (Micropternus brachyurus) nests in a hole excavated in the ball-shaped nest of Crematogasler (the red ants). The eggs, young, and adults of the birds do not suffer from the ferocious ants moving in the nest. The birds live on these ants. This can be said to be nature’s way of keeping the ant population within limits.
• Biological Control. Controlling the population of harmful organisms by means of their natural predators, parasites, or pathogens for example Cactoblastis (cochineal insect) to control Opuntia; woodpecker (Micropternus) to control red ant; Zygogramma (beetle) to control Parthenium weed; Gambusia (minnow fish) to control mosquito larvae, etc.
• Smoother Crops. Crops that do not allow the weeds to grow in the fields for example Sunflower, Barley, Rye, Soyabean, Millet, etc.

NEET Biology Organisms and Populations Commensalism

It is an association of two species in which one lives attached to another but does not harm it. One who is benefited is called commensal.

Organisms And Populations Class 12 Notes For NEET

NEET Biology Organisms and Populations Mutualism

It is a relationship between two species or organisms where both partners are benefited from each other.

Mutualism Examples

1. Lichens. It is an association between fungi (protrusion, fixation, and absorption) and algae (food) which is sometimes described, as Consortium.
2. Zoophily. Several types of animals are involved in the pollination mechanism. Many insects such as bees, moths, butterflies (entomophily), and birds (ornithophily) are involved in the pollination of (lowers when they visit them for food in the form of nectar.
3. Zoochory. Several animals bring about the dispersal of seeds when they visit plants in search of food. A reference of all such plants may be given here whose seeds are dispersed by birds or mammals. They possess several specific anemochorous adaptations in their seeds or fruits.
4. Mycorrhiza. The fungal mycelium found associated to the ‘roots’ of higher plants, the Mycorrhizae are also good examples of mutualism. It may be ‘ectotrophic or endotrophic’. The fungal partner gets food and shelter from the roots of higher plants and their hyphae substitute for the root hair of the host, thus helping in absorption.

Ecological Succession Stages NEET Biology

The mutualistic association is also seen in between many organisms for example, between alga Aphanocapsa and Ircinia, alga Zoochlorellac and flagellate Zooxanthellae and Hydra, and alga Zoochlorellae and Paramecium are worth mentioning. The alga protects the host cell by providing it with food and oxygen. In return, it gets protection.

NEET Biology Organisms and Populations Amensalism

It is a relationship in which one population is adversely affected while the other stays unscathed. The detrimental effect is attributable to certain molecules known as allochemics. There are three categories: allomones, kairomones, and depressants.

• Allomones are chemicals that confer adaptive benefits to the organism that emits them, such as the ink emitted by the mollusk Loligo.
• Kairomones are compounds that confer an adaptive benefit to the recipient population, such as those emitted by some nematodes that promote the growth of specific fungi.
• Depressants are substances secreted by an organism that lethally affect the receiver population.
• The alga Microcystis secretes hydroxylamine, which exterminates the adjacent fauna while remaining impervious itself.
• Antibiosis. A relationship between two species that is detrimental to one of them. For instance, allelomorphy.

NEET Biology Organisms and Populations Protocooperation

It is a type of relationship that is beneficial to both partners but it is not obligatory for their survival. This relationship has been also termed by some workers as non-obligatory mutualism. Some large birds nest on the lower branches whereas the small ones live much higher. These large birds protect the small ones from tree-climbing predators.

Examples Of Competition

• Frank (1957) Daphnia pulicaria causing the extinction of D. magna in mixed cultures.
  • Feeding behavior of cormorant (a bottom feeder of flat fish) and shag (a surface feeder of herrings and eels) by Lack (1945).
  • Feeding behavior of seven species of millipedes on the forest floor of a maple oak forest by O. Neill (1967).
• Darwin’s finches (14 species of passerine birds) on the Galapagos islands (Lack, 1947).
  • Lotka (1925) and Volterra (1926) gave a mathematical model for interspecific competition.

Organisms And Populations Class 12 Notes For NEET

NEET Biology Organisms and Populations Mimicry

The phenomenon in which a particular harmless species of animal shows similarity to another species of animal which is dangerous, poisonous, or distasteful so to avoid its enemies.

Kinds Of Mimicry

1. Protective mimicry
   • Carausius morasus (stick-insect or walking stick) The body and body appendages are long, slender like thin and dry branches.
   • Phyllium frondosurn (leaf-insect). The body is flat and green like a leaf.
   • Kallima paralecta (dead-leaf butterfly). The body looks like a dead and dry leaf when it rests on an oak tree.
   • Cryptolithodes (white crab) resemble the white pebbles.
   • Phyllopteryx (Australian sea horse) produces leafy outgrowths like seaweeds.
2. Aggressive Mimicry
   • Concealing types or aggressive mimicry for example yellow spider (predator) sitting on marigold flowers is invisible to insects (prey).
   • Alluring type or aggressive mimicry for example the comer of an African lizard resembles a flower.
   • Ophyrous flowers resemble female wasps and thus get pollinated by male wasps.
3. Feigning death or Conscious mimicry.
   • Stimulation Of Dkatii (Conscious Mimicry): Certain animals exhibit eonseimis imitation on the approach of danger and behave as if they are dead bodies. A few examples are cited below:
     1. American Opossum ‘Diddphis virginiam’ becomes unconscious and simulates as dead.
     2. Haiti-bodied beetles fall down like pebbles when they are about to be seized by the enemy.
4. In Warning Type Protective Mimicry. The mimic resembles a distasteful or poisonous organism example, a palatable species of Viceroy butterfly (Bosilarchia archippus) resembles a distasteful Morarch utterly Donasais platypus) also termed Halesian mimicry.
5. In Mullerian mimicry. Two or more unpalatable and related species resemble each other.
   • Examples Of Mimicry
     • Elephants and rhinos have colors similar to tree trunks and mud.
     • Lions and camels are sand colored.
     • Praying mantis, tree frog hyla. Grasshoppers are green in color.
     • Jellyfish and sea cucumbers are glassy.
     • Chameleons is able to change their color according to the background.
     • Camouflage. The color pattern of animals blends with their environment so as to minimize the risk of predation.
   • Conditions Necessary for Mimicry
     • The necessary conditions for the occurrence of protective mimicry have been analyzed by Wallace and are listed below:
     • The mimics of the imitative species occur in the same area which are occupied by the models.
     • Mimics are always or more often defenceless and they mimic the offensive or harmful animals.
     • Mimics are always fewer in number than the model individuals so the deceived animal encounters the mimics less often than the model.
     • The imitators should differ from their allies.
     • Even if the imitation is minute, it should be external and visible.

Ecological Succession Stages NEET Biology

NEET Biology Organisms and Populations Significance Of Mimicry

The main significance of mimicry appears to be the protection of individuals against enemies. This self-defense is naturally of survival value and of evolutionary significance. It means natural selection which is supposed to be one of the most important factors in evolution, favors mimicry since it assures better survival and greater success in the multiplication of race.

NEET Biology Organisms and Populations Polymorphism

The colony is formed of two types of individuals who differ in structure function or behavior.

1. Apis indica. Colonial, Social insect. Queen, Workers or Drones.
2. Termite, White Ant (Microtreme) have 5-caste:
   • Queen
   • Workers
   • Nasutes
   • Drones
   • Soldiers
3. Portuguese Man Of War (Physalia) has zooids that show polymorphism
   • Dactylozooids – for defence,
   • Gastrozooids – for feeding.
   • Gonodendra – for reproduction.
   • Pheumatophore – for floating.
4. Obelia – Trimorphic coelenterates:
   • Polyp – for nutrition.
   • Blastostyle – for Medusae formation.
   • Medusa – for sexual reproduction.
5. Volvox (colonial protist) – Formed of about 500-60,000 cells.
   • Peripherally located vegetative zooids (with flagella)-For locomotion and nutrition.
   • Internally located reproductive zooids for multiplication.
6. Show polymorphism in their flower coloration
   • Lathyrus odoratus – Sweet Pea
   • Rosa indica – Rpse
   • Violva tricolor – Pans

Differences Between Climate And Weather

Microclimate. It represents the climatic conditions that prevail at a local scale or in an area of limited size.

Environment. The sum total of all the biotic and abiotic factors that surround and potentiality of the environment serve as a resource, while others act as regulatory factors.

Habitat is the native environment of an animal or place.

Niche. The position or function of an organism in a community of plants and animals.

Landscape. It is a unit of land with a natural boundary having a mosaic of patches.

Individual Organism, is the most concrete and easily ob-servable unit in the environment because it is a distinct package carrying out life processes within its body as a distinct entity.

Acclimatization. The gradual physiological adjustment to slowly changing new environmental conditions is known as acclimatization. If some factors shift beyond the tolerance range of an organism, the organism can continue to the resting stage, migrate, or it can acclimatize.

Ectotherms (Cold Blooded Animals). The body temperature changes along with the change in environmental temperature. Frogs and snakes control their body temperature by moving around or seeking shade or undergoing hibernation.

Endotherms. They regulate their body temperature by physiological means and maintain a constant temperature Irrespective of changes in the temperature of surroundings, Birds and mammals have physiological mechanisms for keeping the body temperature constant.

Salinity is due to the accumulation of soluble minerals on the surface or beneath the surface of the earth.

• The permeability of soil is due to the colloidal nature of the soil.
• Plants die in water-logged soils due to the absence of air. Yak is adapted to very cold temperatures.
• The natality rate (birth rate) number of individuals born per 1,000 individuals of a population per year.

Ecological Succession Stages NEET Biology

Changes In Population Are Expressed As Follows:

N_t = N₀ + B + I – D – E

N_t = Increase in size

N₀ = Initial size

B = Natality rate

I = Hate of immigration

D = Mortality rate

E = Rate of emigration.

J-shaped and S-shaped are the two forms of growth curves.

J-shaped growth curve is represented as \(\frac{d N}{dt}\) = rN

⇒ \(\frac{d N}{dt}\) = rate of change in population size

r = Biotic potential

N = Population size

Equation For S-Shaped Growth Curve: \(\frac{d N}{dt}\) = iN(\(\frac{k -N}{K}\))

k – N/k or 1 – \(\frac{N}{k}\)

NEET Biology Organism And Environment Species And Population Synopsis

Swell Wright Effect. Also called Genetic drift. It is the change in gene frequency due to random fluctuations in small isolated populations causing certain alleles to be lost while other alleles become more evenly distributed.

Schrveter and Kirchner coined the terms autoecology and synecology.

• Ecology = Environmental biology
• Term Bioccology was used by Shelford and Clements for the study of both plant and animal ecology.
• Pheromones. 3 types—Primer Pheromone (example, Locustrol), Rcleaser pheromone (for example, Alarm hormone of worker ant), and Informer pheromone (provides information example, trail substance).
• Population with an equal number of births and deaths shows a plateau phase.
• Competition is severe in a population that has an irregular distribution
• Carrying capacity does not directly affect the biotic potential.
• Cross-fertilization is a kind of cooperative interaction among animals
• Population dynamics. Study of changes in growth and density of population in relation to various parameters.
• The country with negative growth is Austria.
• Amphimictic population. The population whose members reproduce sexually.
• Apomictic population. The population whose members reproduce asexually.
• International Literacy Day falls on 9th September.
• Toxicology: a term used by Mivort for ecology.
• Ethology: the term was used in Hilaril for ecology.
• Insect society is a product of instinctive behavior and Biological evolution whereas the human population is a product of learned behaviour.
• In aquatic organisms, population density is expressed in cubic meters/cubic centimetre
• Rats do not have any fixed partners

Major Biomes With Respect To Annual Temperature And Precipitation

1. Deserts
2. Grasslands
3. Arctic and alpine tundra
4. Tropical forests
5. Temperate forest
6. Coniferous forests.

Major Biomes Of India (Key Conditions: temperature, light, water and soil)

1. Deserts (Rajasthan and parts of Gujarat)
2. Tropical rainforests (Northeastern states)
3. Sea Coast
4. Deciduous forests
5. Torrential stream
6. Permafrost polar regions
7. High mountain tops
8. Boiling thermal springs
9. Stirling compost pits.

Major Abiotic Factors

1. Temperature
2. Water
3. Light
4. Soil
5. Air
6. Rainfall
7. Humidity

Response To Abiotic Factors: To maintain the constancy of the internal environment.

1. Regulate
2. Confirm
3. Migrate
4. Suspend

Adaptations: They enable the organism to survive and reproduce

Populations:

Population Growth:

• Natality
• Mortality
• Immigration
• Emigration

Exponential Growth: J-Shaped Growth Curve

⇒ \(\frac{d N}{dt}\) = (b-d)N-S

Let (b-d) = r then \(\frac{d N}{dt}\) = rN

Logistic growth (S-shaped growth curve) \(\frac{d N}{dt}\) = rN (\(\frac{K -N}{K}\))

N = Population density at time

r = intrinsic rate of natural increase,

K = carrying capacity

Population Interactions

• Mutualism – Lichens, Mycorrhiza
• Commensalism – Orchid growing on mango tree, Sea anemone and clown fish
• Amensalism – Penicillium does not allow growth of Staphylococcus
• Predation – Starfish piaster, Prickly pear cactus
• Parasitism – Liver fluke parasite on snails and fish.
• Competition – Larger superior Barnacle Balanus dominates smaller Barnacle Chethamalus in the intertidal area.