NATURAL RESOURCES-8th Standard Social Science Notes

NATURAL RESOURCES

I. Fill in the blanks with suitable words

1. In recent times, man has moved towards ________ development by controlling environmental pollution and conservation of nature.

2. The amount of pure water available on the surface of land for human use is _________

3. Water is a renewable natural resource, but mineral oil is a _________

4. Plants, by the process of photosynthesis, absorb atmospheric ______________ and release __________

5. If deforestation continues at the same pace, within a few years, __________ state will become the largest desert of our country.

Ans: (1) forest (2) 0.03% (3) non-renewable

(4) Carbon dioxide, oxygen (5) Karnataka

II. Answer the following in a sentence each:

1. What is meant by 'Natural Resources'?

Ans: The resources that nature has given us are called 'Natural
Resources'.

2. What is the meaning of 'Desertification"?

Ans: The destruction of forests and living beings on earth leads to the creation of deserts. This is called desertification.

3. What do you mean by 'Ecological Balance'?

Ans: There is a close link between the innumerable species of animals, plants and man. When the number of animals, human beings and plants complement one another and all beings can live, in peace, such a state is called ecological balance.

4. Which are the gases identified as 'green-house gases'?

Ans: Gases like carbon dioxide, methane, chlorofluorocarbons, ozone and others.

5. What is meant by the earth's 'carrying capacity'?

Ans: Earth is capable of enduring the pressure of population increase, deforestation, environmental pollution, depletion of ground water, excessive use of vehicles, etc., to a certain extent. This is called the earth’s Carrying capacity.

6. What is the main reason for depletion of underground
water table?

Ans: Excess use of ground water through bore wells is the reason for the depletion.

III. Answer the following in 5-6 sentences each :

1. How are the natural resources essential for human life?

Ans: 1) Man's life depends on natural resources. His economic activities have evolved depending on the natural resources. 2) Pleasant weather, fertile soil and abundant water enable agricultural development; 3) mineral resources provide the raw material and fuel necessary for the industrial development. 4) Forest resources not only provide timber and other products needed by man but also regulate the atmosphere. 5) Water helps in agricultural irrigation, production of electricity, industrial development and domestic consumption.

2. 'Plants are the atmospheric purification factories' Explain.

Ans: Plants and trees in the forest provide food and shelter to man and all birds and animals. They preserve the balance between oxygen and carbon dioxide in the atmosphere. Forest brings rain. They also give timber, fire wood and other products. They enable environmental protection and development.

3. What are renewable natural resources? List them.

Ans: Some natural resources go on getting replenished as we use them. These resources are called non-exhaustible resources. Nature, through its natural processes, goes on replenishing them. They are also called renewable resources. Water, land, forests, air, sunlight and heat are some of the renewable resources.

4. What are the non-renewable natural resources? Why should they be used carefully?

Ans: Some natural resources get depleted as we go on using them. Eventually they get dried up too, and cannot be created again. These resources are known as exhaustible resources. Minerals like iron ore, copper, gold, manganese, bauxite, etc., mineral fuels like coal, petroleum, natural gas, uranium, thorium etc., resources which get depleted and cannot be renewed. Nature cannot replenish them through its processes and so they are also known as non-renewable resources.

5. List out the effects of climatic changes.

Ans: The effects of climate are-

(1) Due to global warming, the ice cap in the Polar Regions
and the mountainous peaks will melt and raise the level of the sea and many coastal towns and cities will be
submerged.

(2) More surface water gets evaporated due to the rise of
heat in the atmosphere.

(3) When the amount of carbon dioxide increases in the
atmosphere, heat waves arise which are harmful to plant
and animal species.

(4) Due to temperature rise, the ice on the mountains, the glaciers melt flooding the river valleys and result in soil erosion.

(5) The rising temperature of the tropical zones spreads to Polar Regions, and causes oceanic currents and change in the direction of the oceanic currents.

(6) Marine life suffers due to the atmospheric change. There will be adverse effects on their feeding, reproductive activities and Lifestyle.

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