Biological Science Classes VI-X for School Assistants and TET Paper 2A · Chapter 9

Natural Resources, Biodiversity, Pollution, Global Issues and Conservation

What to remember

Natural resources are renewable (air, water, forests, solar energy) or non-renewable (coal, petroleum, natural gas, minerals); wise use means reduce, reuse and recycle.
Biodiversity is the variety of life at three levels (genetic, species, ecosystem) and is protected in situ (national parks, sanctuaries, biosphere reserves) and ex situ (zoos, botanical gardens, gene banks).
Main global issues are the greenhouse effect and global warming, ozone depletion, acid rain and pollution; the main response is law, international agreements and sustainable living.

Natural resources

Anything in nature that people use is a natural resource.

Type	Meaning	Examples
Renewable	Can be replaced naturally in a short time if used wisely	Air, water, soil, forests, sunlight, wind
Non-renewable	Formed over millions of years; will be exhausted	Coal, petroleum, natural gas, minerals

Fossil fuels (coal, petroleum, natural gas) were formed from dead plants and animals buried for millions of years. They give energy but cause air pollution and release carbon dioxide. Alternative energy: solar, wind, tidal, biogas, hydro and geothermal energy. These do not run out and pollute little.

Forests give wood, fruits, medicines and shelter. They keep soil, bring rain, absorb carbon dioxide and are home to wildlife. Deforestation (cutting down forests for farms, mining and roads) leads to soil erosion, floods, loss of habitat and climate change. Afforestation is planting trees in a bare land; reforestation is replanting where a forest was cut. Water: only a small part of the earth's water is fresh and usable. Rainwater harvesting, drip irrigation and stopping leaks save water. Soil: erosion is reduced by plants, terracing and contour farming.

Sustainable development means meeting today's needs without harming the needs of future generations. The 3 Rs: Reduce, Reuse, Recycle.

Biodiversity

Biodiversity is the variety of all living things on earth. The term "megadiversity" is used for countries that have a very large variety of species; India is one of them.

Genetic diversity: variation within a species (many varieties of rice or mango).
Species diversity: the number of different species in an area.
Ecosystem diversity: the variety of habitats such as forest, desert, wetland and coast.

Biodiversity is greatest in the tropical rain forests and coral reefs. It gives food, medicines, raw materials and ecological balance. It is lost by habitat destruction, hunting and poaching, pollution, introduced (alien) species and climate change.

Categories of species: extinct, endangered, vulnerable and rare. The Red Data Book (IUCN) lists threatened species. An endemic species is found only in one region. A biodiversity hotspot is a region with many endemic species that is under serious threat. India has hotspots in the Western Ghats, the Himalayas, Indo-Burma and the Nicobar islands. The Eastern Ghats, which run through Andhra Pradesh, are also biologically rich.

Conservation of biodiversity

Method	Meaning	Examples
In situ (in the natural habitat)	Protecting species where they live	National parks, wildlife sanctuaries, biosphere reserves, sacred groves
Ex situ (outside the habitat)	Protecting species away from their habitat	Zoos, botanical gardens, seed banks, gene banks, cryopreservation

Protected areas in Andhra Pradesh (examples): Nagarjunasagar-Srisailam Tiger Reserve (one of the largest tiger reserves in India); Sri Venkateswara National Park and the Sri Lankamalleswara and Nelapattu sanctuaries; Papikonda National Park on the Godavari; Coringa Wildlife Sanctuary (mangroves); Pulicat lake bird sanctuary on the coast; Kolleru lake, a wetland and bird habitat; Rollapadu Wildlife Sanctuary, known for the Great Indian Bustard. Check the latest official list for the current status of each area.

Wildlife laws and programmes: Wildlife (Protection) Act, 1972; Project Tiger (1973); Project Elephant; the Biological Diversity Act, 2002. People's movements: Chipko (hugging trees in the Himalayas) and the Bishnoi community's protection of trees and animals in Rajasthan.

Pollution

Pollution is the addition of harmful substances to air, water or soil. A substance that causes pollution is a pollutant.

Type	Main causes	Effects
Air	Smoke from vehicles and factories (carbon monoxide, sulphur dioxide, nitrogen oxides, particles)	Asthma, bronchitis, acid rain, smog
Water	Sewage, factory waste, fertilisers and pesticides, oil spills	Water-borne diseases (cholera, typhoid), death of fish
Soil	Plastic, chemicals, excess fertiliser, solid waste	Loss of fertility
Noise	Vehicles, loudspeakers, machines	Hearing loss, stress, sleeplessness
Thermal	Hot water from power plants	Less oxygen in water, harm to fish
Radioactive	Nuclear accidents, waste	Cancer, genetic damage

Eutrophication: nitrates and phosphates from fertilisers and sewage make algae grow too fast in a lake. When the algae die and decay, bacteria use up the oxygen and fish die. BOD (biochemical oxygen demand) is the amount of oxygen needed by microbes to break down organic matter in water; a high BOD means polluted water. Biodegradable wastes (vegetable waste, paper) are broken down by microbes; non-biodegradable wastes (plastic, DDT, glass) are not. Smoke particles and carbon monoxide are harmful because carbon monoxide combines with haemoglobin and reduces oxygen carried by blood.

Controlling pollution: catalytic converters and unleaded fuel, chimney filters, treatment of sewage, composting, using cloth or jute bags instead of plastic, planting trees, and burning less crop residue and fuel.

Global issues

Greenhouse effect: gases such as carbon dioxide, methane, nitrous oxide, water vapour and CFCs trap heat near the earth. A natural greenhouse effect keeps the earth warm. An increase in these gases, mainly from burning fossil fuels and deforestation, causes global warming: melting of glaciers, sea level rise, and changes in rainfall and weather.
Ozone layer depletion: ozone in the stratosphere absorbs harmful ultraviolet rays. CFCs (from old refrigerators and aerosols) release chlorine that breaks down ozone. This creates the "ozone hole" over Antarctica. The Montreal Protocol (1987) is the international agreement to phase out ozone-depleting substances.
Acid rain: sulphur dioxide and nitrogen oxides combine with rain water to form acids. It damages buildings, soil, plants and lakes.
Plastic waste: plastic does not decompose and harms animals, drains and soil.
E-waste: old computers and phones contain toxic metals and need proper recycling.

Important agreements and days: the Kyoto Protocol (1997) and the Paris Agreement (2015) on climate change; the Ramsar Convention (1971) on wetlands; the Earth Summit at Rio (1992). World Environment Day: 5 June. World Wetlands Day: 2 February. Earth Day: 22 April.

Waste management

Waste can be sorted at home into wet (kitchen and garden waste) and dry (paper, plastic, metal, glass). Wet waste can be made into compost or biogas. Dry waste can be recycled. Hazardous waste, such as batteries, medicines and e-waste, should be given to proper collection centres. Burning plastic produces toxic gases. Sewage treatment removes solids and microbes from used water before it is released. Plants such as water hyacinth can grow quickly in polluted water and block lakes, so they are managed with care.

Role of the individual

Simple actions help: switch off lights and fans when not needed, walk or use a bicycle or public transport for short trips, plant and look after trees, avoid single-use plastic, save water, and do not buy products made from endangered animals. Children in school can lead awareness through rallies, posters and tree-planting on Vana Mahotsav, a yearly tree-planting week held in July.

Indian environmental laws

The Water (Prevention and Control of Pollution) Act, 1974; the Air (Prevention and Control of Pollution) Act, 1981; the Environment (Protection) Act, 1986. The Central and State Pollution Control Boards monitor pollution.

Teaching angle: use field work (a school-garden compost pit, a pollution survey of the locality, rainwater harvesting model), role play (a village meeting about a forest), and projects like a paper-recycling activity. Let students form an eco-club.

Water, soil and energy: key points

Only a small share of the earth's water is fresh and easy to use, so wasting water harms everyone. Rainwater harvesting collects rain from roofs and fields and lets it sink into the ground to raise the groundwater level. Watershed management treats a whole catchment area with check dams, tree planting and ponds. For soil, practices such as crop rotation, mulching and use of compost and green manure keep it fertile. For energy, using LED bulbs and solar cookers lowers the demand for fossil fuels.

Exam traps

Renewable resources (forests, water, wind) are not the same as inexhaustible; forests can be depleted if overused.
In situ conservation is in the habitat; ex situ is outside it.
National park (strict protection, no grazing) is not the same as a sanctuary (some human activity allowed).
CFCs damage the ozone layer; carbon dioxide and methane increase global warming.
Greenhouse effect is a natural process; global warming is its enhancement.
High BOD means more pollution and not cleaner water.
Eutrophication is caused by nutrient enrichment, not by oil spills.
Montreal Protocol is about the ozone layer; Kyoto and Paris are about climate change.

One-liners

1. Coal and petroleum are non-renewable resources.
2. Planting trees on bare land is afforestation.
3. The Red Data Book lists threatened species.
4. Zoos and botanical gardens are ex situ conservation.
5. Biosphere reserves, parks and sanctuaries are in situ conservation.
6. Project Tiger began in 1973.
7. The Wildlife Protection Act was passed in 1972.
8. Carbon monoxide reduces the oxygen-carrying capacity of blood.
9. CFCs deplete the ozone layer.
10. The Montreal Protocol was adopted in 1987.
11. World Environment Day is on 5 June.
12. Chipko is a movement to save trees.

Practice questions

Which of the following is a non-renewable resource?
1. Wind
2. Coal
3. Sunlight
4. Forest
Answer
B. Coal
Coal took millions of years to form.
Planting trees in a place that never had a forest is called
1. deforestation
2. erosion
3. reforestation
4. afforestation
Answer
D. afforestation
Reforestation is replanting where a forest was cut.
Which of the following is an example of ex situ conservation?
1. Biosphere reserve
2. Zoo
3. National park
4. Wildlife sanctuary
Answer
B. Zoo
Zoos protect species outside their natural habitat.
The Red Data Book gives information about
1. water pollution levels
2. mineral resources
3. soil types
4. threatened species
Answer
D. threatened species
It is maintained by the IUCN.
Which gas is mainly responsible for the depletion of the ozone layer?
1. Carbon dioxide
2. Methane
3. Chlorofluorocarbons (CFCs)
4. Oxygen
Answer
C. Chlorofluorocarbons (CFCs)
CFCs release chlorine in the stratosphere.
Which of the following is a greenhouse gas?
1. Neon
2. Methane
3. Argon
4. Helium
Answer
B. Methane
Carbon dioxide, methane and nitrous oxide trap heat.
The Montreal Protocol (1987) deals with
1. control of noise
2. protection of the ozone layer
3. conservation of wetlands
4. protection of tigers
Answer
B. protection of the ozone layer
It phases out ozone-depleting substances.
Acid rain is mainly caused by
1. oxygen and nitrogen
2. sulphur dioxide and nitrogen oxides
3. carbon monoxide only
4. helium and neon
Answer
B. sulphur dioxide and nitrogen oxides
These gases form acids when they dissolve in rain.
The Wildlife (Protection) Act was enacted in
1. 1962
2. 1992
3. 1982
4. 1972
Answer
D. 1972
It is the main law for wildlife protection in India.
Project Tiger was launched in
1. 2002
2. 1985
3. 1973
4. 1950
Answer
C. 1973
It aims to protect tigers in reserves.
World Environment Day is observed on
1. 5 June
2. 16 September
3. 22 April
4. 2 February
Answer
A. 5 June
22 April is Earth Day; 2 February is World Wetlands Day.
The Chipko movement was started to
1. clean rivers
2. save tigers
3. stop noise
4. save trees
Answer
D. save trees
People hugged trees to stop felling.
Which of the following protected areas is a mangrove sanctuary in Andhra Pradesh?
1. Rollapadu
2. Nelapattu
3. Coringa
4. Sri Venkateswara
Answer
C. Coringa
Coringa lies on the Godavari delta.
Rollapadu Wildlife Sanctuary in Andhra Pradesh is known for the
1. Bengal tiger
2. Asiatic lion
3. Great Indian Bustard
4. Olive Ridley turtle
Answer
C. Great Indian Bustard
The sanctuary protects this grassland bird.
Nagarjunasagar-Srisailam is a
1. botanical garden
2. seed bank
3. zoo
4. tiger reserve
Answer
D. tiger reserve
It is one of the large tiger reserves of India.
Which of the following is a non-biodegradable waste?
1. Banana peel
2. Plastic bag
3. Cotton cloth scrap
4. Paper
Answer
B. Plastic bag
Microbes cannot break down plastic easily.
Carbon monoxide is harmful because it
1. combines with haemoglobin and reduces oxygen supply
2. destroys white blood cells
3. increases the heart size
4. dissolves in blood plasma
Answer
A. combines with haemoglobin and reduces oxygen supply
It binds to haemoglobin strongly.
Excessive growth of algae in a lake due to extra nutrients is called
1. nitrification
2. biomagnification
3. speciation
4. eutrophication
Answer
D. eutrophication
Decay of dead algae lowers dissolved oxygen.
A high BOD value of a water sample indicates
1. low microbial activity
2. heavy organic pollution
3. high oxygen
4. clean water
Answer
B. heavy organic pollution
Microbes use a lot of oxygen to decompose waste.
Reducing the use of single-use plastic bags is an example of
1. Reduce
2. Recycle
3. Renew
4. Recover
Answer
A. Reduce
The first of the three Rs is to use less.
Which action helps to reduce global warming?
1. Burning plastic
2. Using more petrol
3. Planting trees
4. Cutting forests
Answer
C. Planting trees
Trees absorb carbon dioxide.
A region with a large number of endemic species that is under threat is called a
1. tiger reserve
2. wetland
3. sanctuary
4. biodiversity hotspot
Answer
D. biodiversity hotspot
Western Ghats is an example.
Genetic diversity refers to
1. number of species in a region
2. number of habitats
3. variation within a species
4. variety of ecosystems
Answer
C. variation within a species
For example many varieties of rice.
Which of these is an in situ conservation method?
1. Botanical garden
2. Biosphere reserve
3. Cryopreservation
4. Seed bank
Answer
B. Biosphere reserve
Species are protected in their natural habitat.
A village pond has turned green and fish are dying. The most probable cause is
1. too much sunlight only
2. fertiliser run-off causing algal bloom
3. too many frogs
4. absence of wind
Answer
B. fertiliser run-off causing algal bloom
Eutrophication reduces oxygen.
Why is thermal pollution harmful to fish?
1. Hot water holds less dissolved oxygen
2. It adds carbon dioxide
3. It removes salt
4. It makes water heavier
Answer
A. Hot water holds less dissolved oxygen
Warm water has less dissolved oxygen.
Which of the following best defines sustainable development?
1. Meeting present needs without harming future generations
2. Using all resources quickly
3. Stopping all development
4. Using only imported resources
Answer
A. Meeting present needs without harming future generations
It balances development and conservation.
Which of the following wetlands in Andhra Pradesh is a famous bird habitat?
1. Srisailam
2. Papikonda
3. Kolleru
4. Nagarjunasagar
Answer
C. Kolleru
Kolleru is a large freshwater lake and wetland.
Ozone layer is present in the
1. exosphere
2. troposphere
3. mesosphere
4. stratosphere
Answer
D. stratosphere
It absorbs harmful ultraviolet rays.
Which of the following correctly matches a law and its subject?
1. Air Act, 1981 — air pollution
2. Water Act, 1974 — noise
3. Environment Act, 1986 — wildlife only
4. Wildlife Act, 1972 — water quality
Answer
A. Air Act, 1981 — air pollution
The Air Act deals with air pollution control.
Burning of fossil fuels increases which gas in the air?
1. Nitrogen
2. Hydrogen
3. Carbon dioxide
4. Helium
Answer
C. Carbon dioxide
It enhances the greenhouse effect.
Which of the following is an alternative (non-conventional) source of energy?
1. Coal
2. Diesel
3. Kerosene
4. Biogas
Answer
D. Biogas
Biogas is made from dung and organic waste.
Statements: 1. National parks and sanctuaries are in situ conservation. 2. Seed banks are in situ conservation.
1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2
Answer
A. 1 only
Seed banks keep seeds away from the habitat, so they are ex situ.
Statements: 1. Fossil fuels are renewable. 2. Wind energy is renewable.
1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2
Answer
B. 2 only
Fossil fuels are non-renewable.
Statements: 1. Greenhouse effect is a natural process. 2. Global warming is caused by an increase in greenhouse gases.
1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2
Answer
C. Both 1 and 2
Both are correct.
Statements: 1. CFCs cause global warming only and do not affect ozone. 2. The Montreal Protocol aimed to stop ozone-depleting substances.
1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2
Answer
B. 2 only
CFCs deplete ozone, so statement 1 is wrong.
Statements: 1. Biodiversity is greatest in polar deserts. 2. Habitat destruction is a major cause of species loss.
1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2
Answer
B. 2 only
Biodiversity is greatest in tropical forests and coral reefs.
Statements: 1. Biodegradable waste can be composted. 2. Plastic breaks down quickly in soil.
1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2
Answer
A. 1 only
Plastic persists for a long time.
Statements: 1. Eutrophication increases oxygen in water. 2. High BOD means clean water.
1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2
Answer
D. Neither 1 nor 2
Eutrophication lowers oxygen, and high BOD means polluted water.
Statements: 1. Chipko was a movement of villagers to save trees. 2. Bishnoi community protects trees and wild animals.
1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2
Answer
C. Both 1 and 2
Both are correct.
Statements: 1. The Red Data Book lists extinct and threatened species. 2. An endemic species is found in many continents.
1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2
Answer
A. 1 only
An endemic species is restricted to one region.
Statements: 1. Acid rain damages buildings and aquatic life. 2. Acid rain is caused by carbon dioxide only.
1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2
Answer
A. 1 only
It is caused mainly by sulphur and nitrogen oxides.
Statements: 1. Kyoto Protocol is about climate change. 2. Ramsar Convention is about wetlands.
1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2
Answer
C. Both 1 and 2
Both are correct.
Statements: 1. Deforestation causes soil erosion. 2. Afforestation increases soil erosion.
1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2
Answer
A. 1 only
Trees hold soil, so afforestation reduces erosion.
Statements: 1. Papikonda is a national park in Andhra Pradesh. 2. Coringa is a tiger reserve.
1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2
Answer
A. 1 only
Coringa is a mangrove wildlife sanctuary.

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1.A statement is given followed by two arguments. Decide which of the arguments is/are strong with respect to the statement. Statement: A minister of country X said, "Shifting to clean sources of energy has become an obvious choice in recent times." Arguments: I. Every year, country X has been witnessing more and more air pollution. II. The prices for coal and natural gasses have increased significantly over the past years.
2.Which of the following is a non-metallic natural resource?
3.Sucrose occurs naturally in-
4.The smallest natural number which is divisible by 48, 72, 16 and 15 is:
5.The smallest natural number which is divisible by 12, 28, 36 and 27 is:
6."Theory of Natural selection" was proposed by -
7.The natural tendency of objects to resist a change in their state of rest or of uniform motion is called ______
8.Rainbow is a natural phenomenon which shows:
9._______ is a natural source of acetic acid.
10.Natural source of vitamin C is-

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