Get summaries, questions, answers, solutions, notes, extras, PDF and guide of Chapter 9 Impact of Resource Depletion, NBSE Class 9 Environmental Education textbook, which is part of the syllabus of students studying under Nagaland Board. These solutions, however, should only be treated as references and can be modified/changed.
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Summary
This chapter explains what happens when natural resources are used up too quickly. It talks about the effects of resource depletion on nature, materials, life, and the economy. The environment has its own way of healing, but human greed disrupts this balance. Overpopulation makes resources like land, water, and food scarce. People use more resources to live comfortably, which harms the environment.
Resource depletion causes four main problems. First, it creates an imbalance in nature. This means less rain, hotter temperatures, and extinction of plants and animals. Cutting down trees, called deforestation, disrupts the air and water cycles. It also causes soil erosion, floods, and landslides. Desertification happens when fertile land turns into desert due to overuse. Ozone layer depletion lets harmful sun rays reach Earth, causing diseases in humans, animals, and plants. Water pollution harms fish and other aquatic life.
Second, there is a shortage of materials. Mining removes valuable minerals from the Earth, but these take millions of years to form. Once they are gone, they cannot return. Groundwater levels are falling because of overuse in farming and cities. Forests are disappearing fast, which means fewer trees for wood and habitat for animals. Non-renewable energy sources like coal and oil are being used up quickly.
Third, the struggle for existence increases. As habitats are destroyed, animals and plants find it hard to survive. Some species have already gone extinct. Humans also face challenges like lack of clean water and food. Oil shortages can lead to fights between countries.
Fourth, economic growth slows down. Natural resources are needed to make goods. When resources are scarce, industries produce less. This affects the economy. Machines, technology, and people work together to produce things. If resources run out, production falls, and so does economic growth.
The chapter explains terms like soil erosion, desertification, and chlorofluorocarbons. It suggests ways to manage resources better. Replanting trees, reducing pollution, and using water wisely can help. The goal is to use resources carefully so they last longer and support life and the economy.
Textbook solutions
Multiple Choice Questions (MCQs)
1. Replanting an area with trees is called:
A. Afforestation
B. Reforestation
C. Deforestation
D. Both (a) and (b)
Answer: D. Both (a) and (b)
2. Removal of vegetation from a piece of land is called:
A. Deforestation
B. Desertification
C. Soil erosion
D. None of these
Answer: A. Deforestation
Very Short Answer Questions
1. What is deforestation?
Answer : Deforestation refers to the removal of vegetation from a piece of land. Trees are removed for wood or for pasturing, cultivation, or settlement.
2. What do you understand by desertification?
Answer : Desertification is a phenomenon of semi-arid or arid areas in which deserts spread to neighboring areas and land is degraded due to climatic variations.
3. Give two causes of soil erosion.
Answer : Two causes of soil erosion are: (i) Excessive use of land (ii) Overgrazing
4. List any two causes of water pollution.
Answer : Two causes of water pollution are: (i) Sewage disposal (ii) Industrial waste disposal
Short Answer Questions
1. What is mining? Name any two minerals?
Answer : Mining is the extraction of valuable materials from the earth, such as metals, uranium, coal, diamonds, limestone, oil shale, rock salt, and others. Two minerals are coal and copper.
2. Give two causes of groundwater depletion?
Answer : Two causes of groundwater depletion are: (i) Deforestation and agricultural practices, such as cultivating rice in areas where average annual rainfall is insufficient, leading to widespread tubewell irrigation. (ii) In big cities, millions of people depend on limited groundwater reserves, causing their levels to keep decreasing.
3. What do you mean by Ozone layer depletion? Explain its causes?
Answer : Ozone layer depletion refers to the gradual thinning of the earth’s ozone layer in the upper atmosphere caused due to the release of chemical compounds containing gaseous bromine or chlorine from industries or other human activities. The main factors responsible for the depletion of the ozone layer are: (i) Chlorofluorocarbons or CFCs, which are released by solvents, spray aerosols, refrigerators, air-conditioners, etc. (ii) Nitrogenous compounds such as NO2, NO, and N2O, which are highly responsible for the depletion of the ozone layer.
4. What is ‘imbalance in nature’? How human causing this imbalance?
Answer : Imbalance in nature refers to the disruptions and alterations in the natural balance of ecosystems, leading to adverse effects on the environment, wildlife, and human beings. Humans cause this imbalance through activities such as deforestation, overpopulation, overexploitation of resources, and habitat destruction. For example, deforestation disrupts the food chain, changes the climate, and leads to soil erosion, desertification, and biodiversity loss.
5. Why are resources considered part of the economy?
Answer : Resources are considered part of the economy because they provide raw materials to industries, which produce goods and services essential for economic growth. Natural resources and technology combined enable large-scale production, employment opportunities, and wealth generation in an economy.
Long Answer Questions
1. How does deforestation bring imbalance in nature?
Answer : Deforestation brings imbalance in nature by causing disruptions and alterations in the natural balance of ecosystems, leading to adverse effects on the environment, wildlife, and human beings. Trees are removed for wood or for pasturing, cultivation, or settlement. When deforestation is not accompanied by reforestation, it leads to imbalance in nature, disruption in the food chain, change in climate, etc. Plants or trees take carbon dioxide from the atmosphere during photosynthesis and release it back into the atmosphere during normal respiration. With the cutting of trees, this cycle gets disrupted, leading to imbalance in nature. Forests also control the hydrological cycle. Trees extract groundwater through their roots and release it into the atmosphere. When a forest is removed, the trees do not evaporate the water, resulting in a dry climate. Deforestation also reduces the content of water in the soil and groundwater, leads to soil erosion that results in floods and landslides, and causes biodiversity loss as many species become extinct.
2. What is desertification and what are its causes?
Answer : Desertification is a phenomenon of semi-arid or arid areas in which deserts spread to neighboring areas, and land is degraded due to climatic variations. The major reasons for desertification are overgrazing, overcultivation, increased fire frequency, water impoundment, deforestation, overdrafting of groundwater, increased soil salinity, and climatic changes.
3. Describe the causes and effects of soil erosion.
Answer : The causes and effects of soil erosion are as follows:
(i) Soil erosion is caused by excessive use of land, overgrazing, deforestation, and similar activities.
(ii) The adverse effects of soil erosion include desertification and the occurrence of floods.
(iii) The removal of fertile agricultural soil adversely affects agricultural productivity.
(iv) Overgrazing leads to the depletion of pasture lands.
(v) Landslides, which are among the most destructive consequences of soil erosion, sweep away entire areas by destroying all vegetation and human structures.
4. Briefly describe the process of ozone layer depletion and its effects.
Answer : The process of ozone layer depletion and its effects are as follows:
(i) Ozone layer depletion refers to the gradual thinning of the Earth’s ozone layer in the upper atmosphere, caused by the release of chemical compounds containing gaseous bromine or chlorine from industries or other human activities.
(ii) Chlorofluorocarbons (CFCs), released by solvents, spray aerosols, refrigerators, air conditioners, etc., are the main cause of ozone layer depletion.
(iii) Nitrogenous compounds such as NO2, NO, and N2O are also highly responsible for the depletion of the ozone layer.
(iv) The major effects of ozone layer depletion on humans and the environment include direct exposure to harmful ultraviolet radiation from the sun, which causes skin diseases, cancer, sunburns, cataracts, quick ageing, and a weakened immune system.
(v) Direct exposure to ultraviolet radiation also leads to skin and eye cancer in animals.
(vi) Strong ultraviolet rays may result in minimal growth, flowering, and photosynthesis in plants, causing forests to suffer from the harmful effects of these rays.
5. What is mining and what is the reason for shortage of minerals?
Answer : Mining is the extraction of valuable materials from the earth, such as metals, uranium, coal, diamonds, limestone, oil shale, rock salt, etc. The reasons for the shortage of minerals are:
(i) Minerals are formed after complex processes spreading over millions of years, but by mining, we extract that material in just a few years. Once mined, any mineral cannot be formed again.
(ii) Several mines have been closed as a result of the total exhaustion of the mineral, for example, the Mesabi range in the USA where iron ore deposits have been totally exhausted.
(iii) At the current speed of mining, many areas would become devoid of minerals.
6. Elaborate the causes of groundwater depletion.
Answer : The causes of groundwater depletion are:
(i) Deforestation and agricultural practices.
(ii) In India, rice is cultivated in many areas where the average annual rainfall is not sufficient for its cultivation. As a result, farmers resort to widespread tubewell irrigation, leading to the exhaustion of groundwater reserves.
(iii) Forest cover helps in the charging of groundwater reserves, but increasing deforestation adversely affects the recharging of groundwater reserves.
(iv) Rainwater goes waste as run-off and is not absorbed by the soil to recharge the groundwater.
(v) In big cities, millions of people depend on limited groundwater reserves, causing their levels to keep going down.
7. Write a note on the struggle for existence.
Answer : The concept of the struggle for existence (or struggle for life) concerns the competition or battle for resources needed to live. It can refer to human society, or to organisms in nature. In today’s environment, competition and struggle for existence can be seen between man and man, state and state, or nation and nation. Struggle for existence is also observed among animals.
Causes of struggle for existence include:
(i) Population increase causing the struggle for existence.
(ii) Changes in the living conditions of animals as a result of resource overexploitation and habitat degradation, which may lead to the extinction of some species.
(iii) Habitat destruction, one of the primary reasons why species of plants and animals are being endangered or driven to extinction.
(iv) Deforestation progressively destroying forest habitats that are home to thousands of animals.
(v) Practices such as overfishing and pollution drastically reducing the number of marine species like tuna fish.
(vi) Extinction of certain animals like the ivory-billed woodpecker, splendid poison frog, Lake Lanao freshwater fish, smooth handfish, bramble cay melomys, spix’s macaw, baiji, and western black rhinoceros. Similarly, 32 orchid species and 65 North American plants have become extinct.
(vii) Adverse effects of oil depletion, including the fall of businesses, high cost of living in developing countries, uncertainty in the transport sector, and international tensions due to competition for remaining oil supplies.
(viii) Approximately two billion people lacking access to clean water due to deforestation and contamination of water sources and groundwater, leading to water shortages, famine, and food insecurity.
8. Write a note on the Slackening of Economic growth.
Answer : Slackening of economic growth refers to the slowdown in the rate at which a country’s economy is expanding. Economic growth is the increase in production and wealth in an economy. The availability of natural resources and their reserves directly affects the economic growth of a country’s economy. Large numbers of resources supply raw materials to many industries, enabling them to produce large quantities of goods. Natural resources and technology are combined to produce goods and services. Large-scale production is possible only when goods are produced using fast and efficient machines, advanced technology, and a large workforce. However:
(i) Man indulges in the fast extraction of all natural resources, leading to their depletion from the earth.
(ii) When resources start depleting, the input of industry is affected, adversely impacting industrial production.
(iii) A decrease in industrial production causes economic growth to fall.
(iv) Therefore, it is suggested that man should use resources wisely so they can last longer and continue to provide inputs to industries, ensuring sustained economic growth.
Extras
Additional questions and answers
1. Define resource depletion?
Answer : Resource depletion refers to the fast depleting natural resources as a result of increasing industrialization, non-equitable distribution, and growing population. It exerts pressure on the environment, leading to environmental degradation and exploitation.
29. Explain how natural resource availability directly affects economic growth.
Answer : Natural resource availability directly affects economic growth in the following ways:
(i) Natural resources provide raw materials to industries, enabling large-scale production of goods and services.
(ii) Large-scale production is possible only when goods are produced with fast and efficient machines, advanced technology, and a large workforce, all of which depend on the availability of resources.
(iii) When natural resources start depleting due to fast extraction, the input of industries is affected, leading to reduced industrial production.
(iv) A decrease in industrial production results in a fall in economic growth.
(v) Therefore, it is suggested that resources should be used wisely so they can last longer and continue providing inputs to industries, ensuring sustained economic growth.
Additional MCQs
1. Which of the following is not an impact of resource depletion?
A. Imbalance in nature
B. Economic growth acceleration
C. Shortage of materials
D. Struggle for existence
Answer: B. Economic growth acceleration
45. Which adverse effect is directly associated with soil erosion?
A. Landslides
B. Urban growth
C. Increased crops
D. Enhanced forests
Answer: A. Landslides
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