NEET Biology Notes – Environmental Issues

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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

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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.

NEET Biology Chapter Wise 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:

Environmental Pollution And Global Environmental Issues Major Pollutants Of Air

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.

NEET Biology Chapter Wise 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.

NEET Biology Chapter Wise Notes

Main Greenhouse Gases

Environmental Pollution And Global Environmental Issues Main Greenhouse Gases

NEET Biology Environmental Issues Ozone Shield

Chlorine from chlorofluorocarbons (CFCs) and bromine from halogens (Cx FxBrx) 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.

Biology Handwritten Notes For NEET

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

Environmental Pollution And Global Environmental Issues 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.

Biology Handwritten Notes For NEET

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.

Environmental Pollution And Global Environmental Issues Noise Pollution

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.

Biology Handwritten Notes For NEET

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

Environmental Pollution And Global Environmental Issues 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.

NEET Environmental Issues Notes

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

Environmental Pollution And Global Environmental Issues Zone Wise Permissiible 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

Environmental Pollution And Global Environmental Issues 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.

Environmental Pollution And Global Environmental Issues Environmental Pollution

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

NEET Environmental Issues Notes

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

NEET Environmental Issues Notes

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 carboxyhemoglobin 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

NEET Environmental Issues Notes

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:

Environmental Pollution And Global Environmental Issues Match The Column Question 41

  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

Biology Handwritten Notes For NEET

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.

Environmental Pollution And Global Environmental Issues Match The Column Question 50

  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. NOX
  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

Biology Handwritten Notes For NEET

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

Biology Handwritten Notes For NEET

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

NEET Environmental Issues Notes

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.

NEET Environmental Issues 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

NEET Environmental Issues Notes

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:

Environmental Pollution And Global Environmental Issues Match The Column Question 46

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

NEET Environmental Issues Notes

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

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