CBSE Class 10 Science Management Of Natural Resources

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This Class 10 Science notes and question bank on Management of Natural Resources covers the types of natural resources, why they must be managed, the conservation of wildlife, water, and forests, the causes and effects of deforestation, the Chipko Movement, rainwater harvesting, a crossword practice set, a question bank with very short, short, long and value based questions, and practical based multiple choice questions with answers.

Topics Covered

1. Natural Resources
2. Why Natural Resources Must Be Managed
3. Conservation of Wildlife
4. Conservation of Water
5. Conservation of Forests
6. Deforestation
7. Chipko Movement
8. Rainwater Harvesting
9. Crossword Practice
10. Question Bank
11. Practical Based Questions

Natural Resources

Natural resources include the total natural environment that supports human life and contributes to the production of necessities and comforts for mankind. Natural resources are therefore the components of the atmosphere, the hydrosphere and the lithosphere.

On the basis of abundance and availability, natural resources are of two types:
(a) Inexhaustible
(b) Exhaustible

Why Natural Resources Must Be Managed

1. The resources of the earth are limited.
2. Proper management prevents the exploitation of natural resources.
3. Proper management ensures equitable distribution of natural resources, so that all people can benefit from their development.
4. Proper management takes into account the damage caused to the environment during the extraction or use of natural resources, and finds ways to minimise this damage.

Conservation of Wildlife

It is very important to conserve wildlife to maintain the ecological balance in nature and to preserve the gene pool.

1. Stringent laws should prevent poaching or capturing of animals.
2. The habitat of wild animals should be preserved by establishing National Parks and sanctuaries.
3. The Forest Department should carry out regular surveys to learn about the population of all species of wild animals and plants.
4. Special attention should be paid to the conservation of endangered species of wild animals and birds, to prevent their extinction.

Conservation of Water

Dams are built to conserve water.

Advantages of Dams

1. Regular, round the year water supply to fields.
2. Continuous water supply to nearby human settlements.
3. Generation of electricity.

Disadvantages of Dams

1. Social problems.
2. Environmental problems.
3. Economic problems.

Conservation of Forests

1. Afforestation
2. Reforestation
3. Separation of commercial forestry
4. Grazing

Deforestation

Removal, decrease or deterioration of the forest cover of an area is called deforestation. It is caused by excessive felling of trees, overgrazing, monoculture, fragmentation and clearing of forests.

Effects of Deforestation

1. Soil erosion
2. Desertification
3. Floods
4. Destruction of wildlife
5. Climatic changes

Chipko Movement

The Chipko Movement was born in the 1970s in a small hilly village in the upper reaches of the Himalayas. Tribal people of the Tehri-Garhwal district of Uttar Pradesh (now Uttarakhand) realised the importance of the forests. They decided against giving forest products to people of other areas, and stood against the ruthless butchery of nature and the axes of greedy contractors.

Rainwater Harvesting

Water harvesting is the capturing, collection and storage of rainwater and surface run-off, either for filling small water bodies or for recharging ground water, so that water continues to be available in non-rainy seasons.

(see Fig. 16.1). Coliform is a group of bacteria, found in human intestines, whose presence in water indicates contamination by disease-causing microorganisms.

[Figure: Figure 16.1 Total coliform count levels in the Ganga (1993-1994), a bar and line graph of the maximum, minimum and annual mean coliform count (MPN per 100 mL) at places upstream and downstream of cities along the river, with a desired level line]

Legend: Maximum/Minimum (red bar); Annual mean (blue line); Minimum Desired level (green line).
MPN: most probable number; mL: millilitre; u/s: upstream; d/s: downstream.

Figure 16.1 Total coliform count levels in the Ganga (1993-1994)

Source: Anon 1996, Water Quality – Status and Statistics (1993 & 1994), Central Pollution Control Board, Delhi, p.11.

[Figure: Figure 16.3 Traditional water harvesting system, showing the catchment area, khadin or cropped area, khadin bund, saline area, seepage, shallow dugwell and the sloping ground]

[Figure: Mind map titled Management of Natural Resources, with the central node Natural Resources (Sustainable Management and Development) and branches for Minerals (recycling, judicial use, alternative materials), Water (water harvesting, pH of water, sources of water pollution, water for all), Coal (thermal power plant, steam engines), Petroleum (save for future generations, non-renewable), Wildlife (preserve the bio-diversity, save wildlife), Forest (biodiversity, role of Chipko Movement), and the three Rs of Recycle, Reduce and Reuse, along with To Save and The Environment]

Crossword Practice: Management of Natural Resources

Across
2. Soil is the cover of the earth's surface.
3. Natural resources that can be replaced are called renewable.
4. Non-domesticated animals and uncultivated plants are wild.
5. To use up a supply or abundance of something is to deplete.
6. Sustainable agriculture requires understanding of natural processes.
7. Many people utilise wildlife resources for recreation.
8. The ability to maintain something at a certain rate or level is sustainability.
9. Substances washing into water sources is run-off.
10. Preserving and protecting the natural environment is conservation.
11. The loss of soil to wind or water is erosion.

Down
1. Resources that cannot be replenished are called non-renewable.

Crossword Practice: Natural Resources

Across
4. A resource that cannot be replaced is non-renewable.
6. An inorganic substance that comes from the earth is a mineral.
7. Items from nature that are of use to humankind are resources.
10. A material put on soil to improve the quality of plant growth is fertiliser.
11. An example of a renewable resource is solar energy.
13. Timber used for building material or paper is wood.
14. Land that is suitable for producing crops is arable.
15. The mineral discovered at Sutter's Mill in California in 1849 is gold.
16. The fur-bearing animal that settlers hunted for is the beaver.

Down
1. A common natural resource we use is water.
2. Mineral resources such as coal and oil are extensively used by humans.
3. Whale oil, and land, was an abundant natural resource for early settlers.
5. A resource that can be used over and over again is recyclable.
8. Oil, coal and natural gas are fossil fuels.
9. An example of a non-renewable resource is petroleum.
12. Supplying water by artificial means is irrigation.

Question Bank: Management of Natural Resources

Very Short Answer Type Questions (1 mark)

1. What is coliform?

Answer: Coliform is a group of bacteria found in human intestines. Their presence in water indicates contamination by disease-causing microorganisms.

Teacher's Note:
a) Coliform counts are measured as MPN (most probable number) per 100 mL of water.
b) Water with a high coliform count is unsafe for drinking without treatment.

2. What are the two kinds of natural resources?

Answer: The two kinds of natural resources are inexhaustible and exhaustible.

Teacher's Note:
a) Inexhaustible resources, such as solar energy and wind, are not used up by human use.
b) Exhaustible resources, such as coal and petroleum, can be used up and are non-renewable.

3. What are the 3 Rs in sustainable development?

Answer: The 3 Rs are Reduce, Reuse and Recycle.

Teacher's Note:
a) Reduce means using less material in the first place.
b) Reuse means using an item again in its original form, while recycling means converting waste into new material.

Short Answer Type Questions (2 marks)

1. List any two common methods by which solid wastes of urban areas are disposed of.

Answer: Two common methods are landfilling, in which waste is buried in low-lying areas, and incineration, in which waste is burnt in a controlled manner. Composting of biodegradable waste is also used.

Teacher's Note:
a) Burning waste in the open is harmful and is not an accepted disposal method.
b) Recycling of plastic, paper and metal also reduces the amount of waste sent for disposal.

2. State an instance where human intervention saved the forest from destruction.

Answer: The Chipko Movement in the Himalayan region saved the forests from destruction. Villagers, including women, hugged the trees to stop them from being felled.

Teacher's Note:
a) The movement began in the 1970s in the Tehri-Garhwal region.
b) The Chipko Movement is a good example of local people protecting forests against commercial exploitation.

3. Name the stakeholders who have their dependence on forests?

Answer: Stakeholders who depend on forests include local and tribal communities, farmers and herders who graze animals, forest-based industries, timber contractors, the Forest Department, and wildlife.

Teacher's Note:
a) Forests provide fuel, fodder, food, medicines and livelihoods to local people.
b) Forest-dependent wildlife is itself a stakeholder, so conservation protects both people and animals.

Short Answer Type Questions (3 marks)

1. How is our holy river Ganga getting polluted? What are its ill effects? What is being done to prevent its pollution?

Answer: The Ganga is polluted by untreated sewage and industrial effluents discharged into it, by agricultural run-off carrying fertilisers and pesticides, and by the disposal of waste and partly burnt bodies on its banks. Its ill effects include the spread of water-borne diseases, since high coliform counts show contamination by disease-causing microorganisms, and harm to aquatic life. To prevent this, the Government has launched the Ganga Action Plan, which builds sewage treatment plants, stops the direct discharge of untreated waste, and promotes public awareness.

Teacher's Note:
a) Refer to Figure 16.1 in the notes above, which shows coliform levels in the Ganga at several places.
b) Treatment of sewage before it reaches the river is the most effective step.

2. With the help of an example, show that the reuse strategy is better than recycling.

Answer: Glass bottles are a good example. A milk bottle that is washed and refilled is reused directly, which needs little energy. When the same bottle is recycled, it must be crushed, melted and remade into a new bottle, which uses a large amount of energy. So reuse saves more energy and resources than recycling.

Teacher's Note:
a) Reuse keeps an item in its original form, whereas recycling changes it into a new material.
b) Recycling is still better than throwing an item away when reuse is not possible.

3. Why is sustainable management of natural resources necessary?

Answer: Sustainable management is necessary so that natural resources are available for future generations, their exploitation is prevented, they are distributed equitably among all people, and the damage caused to the environment during their extraction and use is minimised.

Teacher's Note:
a) The earth's resources are limited, so they must be used carefully.
b) Sustainable management balances development with the protection of the environment.

4. Everyone of us can do something to reduce our consumption of various natural resources. List 4 activities based on the 3 R approach.

Answer: (1) Reduce: turn off taps, fans and lights when they are not needed. (2) Reuse: use old containers and cloth bags again instead of buying new ones. (3) Recycle: send paper, glass and metal waste for recycling. (4) Reuse: repair or give away old clothes, toys and books instead of discarding them.

Teacher's Note:
a) Each activity should be linked to one of the three Rs.
b) Reducing consumption is the first and most effective of the three Rs.

Value Based Question

There are certain NGOs which ask people to donate their used clothes, toys, school books and household items. These NGOs segregate the collected items and distribute them to needy people. What objectives do these NGOs fulfil by these initiatives?

Answer: These NGOs reduce waste by giving used items a second life, and reuse resources that would otherwise be thrown away. They help needy people by providing clothes, books and household items. They also spread awareness of conservation and of the value of sharing among the community.

Teacher's Note:
a) This is a value based question, so the answer should mention both the environmental and the social objectives.
b) Donating used items is an example of the reuse strategy in practice.

Practical Based Questions

1. In an experiment to study the properties of ethanoic acid, a student takes about 3 mL of ethanoic acid in a dry test tube. He adds an equal amount of distilled water to it and shakes the test tube well. After some time he is likely to observe that (a) a colloid is formed in the test tube (b) the ethanoic acid dissolves readily in water (c) the solution becomes light orange (d) water floats over the surface of ethanoic acid.

Answer: (b) The ethanoic acid dissolves readily in water.

Teacher's Note:
a) Ethanoic acid is miscible with water, so the mixture forms a clear solution, not a colloid.
b) Option (d) is wrong because the two liquids mix and do not separate into layers.

2. For preparation of soap in the laboratory we require an oil and a base. Which of the following combinations is best suited for the preparation of soap? (a) Castor oil and calcium hydroxide (b) Turpentine oil and sodium hydroxide (c) Castor oil and sodium hydroxide (d) Mustard oil and calcium hydroxide

Answer: (c) Castor oil and sodium hydroxide.

Teacher's Note:
a) Soap is made by saponification of an oil or fat with a strong alkali such as sodium hydroxide.
b) Turpentine oil is not a fat, and calcium hydroxide does not give a soft soap that is suitable for washing.

3. A sample of water containing excess of calcium ions is called (a) ionic water (b) soft water (c) hard water (d) heavy water.

Answer: (c) Hard water.

Teacher's Note:
a) Soft water has very few dissolved calcium and magnesium salts.
b) Hard water does not lather well with soap, and is numbered 3 here because the source printed 4 twice.

4. A full length image of a distant tall building can be seen by using (a) concave mirror (b) convex mirror (c) plane mirror (d) both a and b.

Answer: (b) Convex mirror. It forms an erect, virtual and diminished image, which covers a wide field of view.

Teacher's Note:
a) A concave mirror forms an inverted image of a distant object at its focus, which is small and cannot show the full building.
b) Option (d) is not correct because a concave mirror does not give a full length image of a distant building.

5. The magnifying power of a convex lens (a) is always greater than 1 (b) is always less than 1 (c) is always 1 (d) can have any value.

Answer: (d) Can have any value.

Teacher's Note:
a) A convex lens used as a simple magnifier gives a magnifying power greater than 1.
b) When the lens forms a diminished image, the magnifying power is less than 1.

6. If the speed of light in a medium is 2 x 10⁸ m/s, then its refractive index is (a) 1 (b) 10 (c) 1.5 (d) 0.5.

Answer: (c) 1.5. Refractive index = speed of light in vacuum / speed in medium = 3 x 10⁸ / 2 x 10⁸ = 1.5.

Teacher's Note:
a) The source printed the speed as "2x 108 m/s"; the power of ten is taken as 10⁸ here.
b) The refractive index can never be less than 1 for a medium, so option (d) is wrong.

7. You are given water, mustard oil, glycerine and kerosene. In which of these media would a ray of light incident obliquely at the same angle bend the most? (a) Kerosene (b) Glycerine (c) Water (d) Mustard oil.

Answer: (b) Glycerine, which has the highest refractive index (about 1.47) of the given media.

Teacher's Note:
a) A ray bends more in a medium of higher refractive index.
b) Mustard oil has a refractive index very close to glycerine, so the difference is small.

8. The law of reflection holds good for (a) plane mirror (b) concave mirror only (c) all mirrors irrespective of their shape (d) convex mirror only.

Answer: (c) All mirrors, irrespective of their shape.

Teacher's Note:
a) The angle of incidence equals the angle of reflection at every point of any reflecting surface.
b) Options (a), (b) and (d) describe only some of the mirror types.

9. A ray of light travelling in a rare medium meets the surface of another denser medium. While entering the second medium at the point of incidence, it (a) goes straight into the second medium (b) bends towards the normal (c) bends away from the normal (d) does not enter at all.

Answer: (b) Bends towards the normal.

Teacher's Note:
a) A ray entering a denser medium slows down and bends towards the normal.
b) Option (a) is true only when the ray falls normally on the surface.

10. In solar devices, the energy is concentrated into a small area using (a) plane mirror (b) concave mirror (c) parabolic mirror (d) parabolic or concave mirror.

Answer: (d) Parabolic or concave mirror.

Teacher's Note:
a) A parabolic mirror is a type of concave mirror, so both (b) and (c) are covered by option (d).
b) A plane mirror does not concentrate light.

11. Image formed in a photographic camera is (a) virtual and diminished (b) real and magnified (c) sometimes real and sometimes virtual (d) real and diminished.

Answer: (d) Real and diminished.

Teacher's Note:
a) The camera lens forms a real, inverted and diminished image on the film or sensor.
b) A virtual image cannot be formed on the film, because light does not actually meet there.

12. In the following diagram, the structure of the embryo of a dicot seed is shown. In this, the parts A and B are sequentially labelled. Choose the correct option: (a) Plumule and radicle (b) Cotyledon and seed coat (c) Radicle and plumule (d) None of these.

Answer: (a) Plumule and radicle. Part A is the plumule, the upper shoot tip, and part B is the radicle, the lower root tip.

Teacher's Note:
a) The cotyledons are the large seed leaves and are not labelled A or B in this figure.
b) The answer depends on the labels in the figure, which should be checked against the printed diagram.

13. What does the following diagram indicate? (a) Budding in yeast (b) Binary fission in amoeba (c) Multiple fission in plasmodium (d) None of these.

Answer: (b) Binary fission in amoeba. The mother amoeba divides into two daughter amoebae.

Teacher's Note:
a) Budding in yeast produces a small bud from the parent cell, which is not shown in the diagram.
b) Multiple fission in plasmodium produces many daughter cells at once, which is also not shown.

14. For tracing the path of a ray of light through a glass prism, the ideal distance between the two pins is (a) 2-3 cm (b) 3-5 cm (c) 6-8 cm (d) 10-15 cm.

Answer: (c) 6-8 cm.

Teacher's Note:
a) Pins placed too close give an inaccurate line of the ray.
b) Pins placed too far apart may fall outside the paper or the prism face.

15. The basic cause of dispersion of white light on passing through a prism is (a) same wavelength of different colours (b) different wavelength of different colours (c) different colours travel through glass prism with same speed (d) none of these.

Answer: (b) Different wavelengths of different colours.

Teacher's Note:
a) Different wavelengths travel at different speeds in glass, so each colour bends by a different amount.
b) Option (c) is wrong because the colours do not travel with the same speed in glass.

16. Wings of an insect and a bird are examples of (a) analogous organ (b) homologous organ (c) vestigial organ (d) analytic organ.

Answer: (a) Analogous organ. They have the same function but different basic structures and origins.

Teacher's Note:
a) Homologous organs have a common origin but may have different functions, such as the forelimbs of humans and whales.
b) Vestigial organs are reduced structures that have lost their original function.

17. Which of the following is/are examples of vestigial organ/organs in humans? (a) cornea (b) appendix (c) canine (d) all of the above.

Answer: (b) Appendix. The printed key "all of the above" is corrected here.

Teacher's Note:
a) The cornea is a functional part of the eye, so it is not vestigial.
b) The canine teeth are functional in humans, although they are reduced in size compared with other primates.

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