NCERT Book Class 8 Science Conservation Of Plants And Animals

CONSERVATIION OF PLANTS AND ANIIMALS

We saw in Class VII that Paheli and Boojho had visited the forest along with Prof. Ahmad and Tibu. They were eager to share their experiences with their classmates. Other children in the class were also eager to share their experiences as some of them had visited Bharatpur Sanctuary. Some others had heard about Kaziranga National Park, Lockchao Wildlife Sanctuary, Great Nicobar Biosphere Reserve and Tiger Reserve, etc.

7.1 Deforestation and Its Causes

A great variety of plants and animals exists on earth. They are essential for the wellbeing and survival of mankind. Today, a major threat to survival of these organisms is deforestation. We know that deforestation means clearing of forests and using that land for other purposes. Trees in the forest are cut for some of the purposes mentioned below:  Procuring land for cultivation.   Building houses and factories.  Making furniture or using wood as fuel.

7.2 Consequences of Deforestation

Paheli and Boojho recalled the consequences of deforestation. They remembered that deforestation increases the temperature and pollution level on the earth. It increases the level of carbon dioxide in the atmosphere. Ground water level also gets lowered. They know that deforestation disturbs the balance in nature. They were told by Prof. Ahmad that if cutting of trees continues, rainfall and the fertility of the soil will decrease. Moreover, there will be increased chances of natural calamities such as floods and droughts.

Recall that plants need carbon dioxide for photosynthesis. Fewer trees would mean that less carbon dioxide will be used up resulting in its increased What is the purpose of making national parks, wildlife sanctuaries and biosphere reserves? amount in the atmosphere. This will lead to global warming as carbon dioxide traps the heat rays reflected by the earth. The increase in temperature on the earth disturbs the water cycle and may reduce rainfall. This could cause droughts. Deforestation is a major cause which leads to the change in soil properties. Physical properties of the soil get affected by plantation and vegetation. Recall from Class VII how trees prevent soil erosion. Fewer trees result in more soil erosion. Removal of the top layer of the soil exposes the lower, hard and rocky layers. This soil has less humus and is less fertile. Gradually the fertile land gets converted into deserts. It is called desertification.

Deforestation also leads to a decrease in the water holding capacity of the soil. The movement of water from the soil surface into the ground (infiltration rate) is reduced. So, there are floods. The other properties of the soil like nutrient content, texture, etc., also change because of deforestation. We have studied in Class VII that we get many products from forests. List these products. Will we face the shortage of these products if we continue cutting trees?

7.4 Biosphere Reserve

Children along with Prof. Ahmad and Madhavji enter the biosphere reserve area. Madhavji explains that biospherereserves are the areas meant for conservation of biodiversity. As you are aware that biodiversity is the variety of plants, animals and microorganisms generally found in an area. The biosphere reserves help to maintain the biodiversity and culture of that area. A biosphere reserve may also contain other protected areas in it. The Pachmarhi Biosphere Reserve consists of one national park named Satpura and two wildlife sanctuaries named Bori and Pachmarhi (Fig. 7.1). a rabbit and wants to catch it. She starts running after it. Prof. Ahmad stops her. He explains that animals are comfortable and happy in their own habitat. We should not disturb them. Madhavji explains that some animals and plants typically belong to a particular area. The plants and animals found in a particular area are termed flora and fauna of that area.

Exercises

1. Fill in the blanks:

(a) A place where animals are protected in their natural habitat is called .

(b) Species found only in a particular area is known as .

(c) Migratory birds fly to far away places because of changes.

2. Differentiate between the following:

(a) Wildlife sanctuary and biosphere reserve

(b) Zoo and wildlife sanctuary

(c) Endangered and extinct species

(d) Flora and fauna

3. Discuss the effects of deforestation on the following:

(a) Wild animals

(b) Environment

(c) Villages (Rural areas)

(d) Cities (Urban areas)

(e) Earth

(f) The next generation

4. What will happen if:

(a) we go on cutting trees.

(b) the habitat of an animal is disturbed.

(c) the top layer of soil is exposed.

5. Answer in brief:

(a) Why should we conserve biodiversity?

(b) Protected forests are also not completely safe for wild animals. Why?

(c) Some tribals depend on the jungle. How?

(d) What are the causes and consequences of deforestation?

(e) What is Red Data Book?

(f) What do you understand by the term migration? 

6. In order to meet the ever-increasing demand in factories and for shelter, trees are being continually cut. Is it justified to cut trees for such projects? Discuss and prepare a brief report.

7. How can you contribute to the maintenance of green wealth of your locality? Make a list of actions to be taken by you.

8. Explain how deforestation leads to reduced rainfall.

9. Find out the information about the national parks in your state. Identify and show their location on the outline map of India.

10. Why should paper be saved? Prepare a list of ways by which you can save paper.

Please refer to attached file for NCERT Class 8 Science Conservation Of Plants And Animals