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NCERT Class VIII Science Chapter 7 Conservation of Plants and Animals
National Council of Educational Research and Training (NCERT) Book for Class VIII
Chapter: Chapter 7 – Conservation of Plants and Animals
Class VIII NCERT Science Text Book Chapter 7 Conservation of Plants and Animals is given below.
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 well being 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.
Some natural causes of deforestation are forest fires and severe droughts.
Add more causes of deforestation to your list and classify them into natural and man-made.
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 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?
Animal life is also affected by deforestation. How? List the points and discuss them in your class.
7.3 Conservation of Forest and Wildlife
Having become aware of the effects of deforestation, Paheli and Boojho are worried. They go to Prof. Ahmad and ask him how forests and wildlife can be saved. Prof. Ahmad organises a visit to a biosphere reserve for Paheli, Boojho and their classmates. He selects a place named Pachmarhi Biosphere Reserve. He knows that the plants and animals found here are similar to those of the upper Himalayan peaks and to those belonging to the lower western ghats. Prof. Ahmad believes that the biodiversity found here is unique. He requests Madhavji, a forest employee, to guide the children inside the biosphere reserve. He explains that preserving areas of such biological importance make them a part of our national heritage.
Biosphere is that part of the earth in which living organisms exist or which supports life. Biological diversity or biodiversity, refers to the variety of organisms existing on the earth, their interrelationships and their relationship with the environment.
Madhavji explains to the children that apart from our personal efforts and efforts of the society, government agencies also take care of the forests and animals. The government lays down rules, methods and policies to protect and conserve them. Wildlife sanctuaries, national parks, biosphere reserves, etc., are protected areas for conservation of plants and animals present in that area.
To protect our flora and fauna and their habitats, protected areas called sanctuaries, national parks and biosphere reserves have been earmarked. Plantation, cultivation, grazing, felling trees, hunting and poaching are prohibited there. Sanctuary : Areas where animals are protected from any disturbance to them and their habitat.
National Park : Areas reserved for wild life where they can freely use the habitats and natural resources. Biosphere Reserve : Large areas of protected land for conservation of wild life, plant and animal resources and traditional life of the tribals living in the area.
Find out the number of national parks, wildlife sanctuaries and biosphere reserves in your district, state and country. Record in Table 7.1. Show these areas in an outline map of your state and India.
7.4 Biosphere Reserve
Children along with Prof. Ahmad and Madhavji enter the biosphere reserve area. Madhavji explains that biosphere reserves 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).
List the factors disturbing the biodiversity of your area. Some of these factors and human activities may disturb the biodiversity unknowingly. List these human activities. How can these be checked? Discuss in your class and write a brief report in your notebook.
7.5 Flora and Fauna
As the children walk around the biosphere reserve they appreciate the green wealth of the forest. They are very happy to see tall teak trees and animals inside the forest. Suddenly, Paheli findsa 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.
Sal, teak, mango, jamun, silver ferns, arjun, etc are the flora and chinkara, blue-bull, barking deer, cheetal, leopard, wild dog, wolf, etc. are examples of the fauna of the Pachmarhi Biosphere Reserve (Fig. 7.2).
Try to identify the flora and fauna of your area and list them.
7.6 Endemic Species
Soon the group quietly enters the deep forest. Children are surprised to see a very big squirrel. This squirrel has a big fluffy tail. They are very curious to know about it. Madhavji tells them that this is known as the giant squirrel and is endemic to this area.
Endemic species are those species of plants and animals which are found exclusively in a particular area. They are not naturally found anywhere else. A particular type of animal or plant may be endemic to a zone, a state or a country. Madhavji shows sal and wild mango (Fig. 7.3 (a)] as two examples of the
endemic flora of the Pachmarhi Biosphere Reserve. Bison, Indian giant squirrel [Fig. 7.3 (b)] and flying squirrel are endemic fauna of this area. Prof. Ahmad explains that the destruction of their habitat, increasing population and introduction of new species may affect the natural habitat of endemic species and endanger their existence.
Species is a group of populations which are capable of interbreeding. This means that the members of a species can reproduce fertile offspring only with the members of their own species and not with members of other species. Members of a species have common characteristics.
Find out the endemic plants and animals of the region where you live.
7.7 Wildlife Sanctuary
Soon Paheli sees a board with ‘Pachmarhi Wildlife Sanctuary’ written on it. Prof. Ahmad explains that, like reserve forests, wildlife sanctuaries provide protection and suitable living conditions to wild animals. Madhavji further explains that sanctuaries are places where killing (poaching) or capturing of animals is strictly prohibited.
Some of the threatened wild animals like black buck, white eyed buck, elephant, golden cat, pink headed duck, gharial, marsh crocodile, python, rhinoceros, etc. are protected and preserved in our wild life sanctuaries. Indian sanctuaries have unique landscapes—broad level forests, mountain forests and bush lands in deltas of big rivers.
It is a pity that even protected forests are not safe because people living in the neighbourhood encroach upon them and destroy them. Children are reminded of their visit to the zoo. They recall that zoos are also places where animals receive protection.
Visit a nearby zoo. Observe the conditions provided to the animals. Were they suitable for the animals? Can animals live in artificial setting instead of their natural habitat? In your opinion, will the animals be comfortable in a zoo or in their natural habitat?
7.8 National Park
On the roadside there was another board on which was written ‘Satpura National Park’. Children are now eager to go there. Madhavji tells them that these reserves are large and diverse enough to protect whole sets of ecosystems. They preserve flora, fauna, landscape and historic objects of an area. Satpura National Park is the first Reserve Forest of India. The finest Indian teak is found in this forest.
Rock shelters are also found inside the Satpura National Park. These are the prehistoric evidences of human life in these jungles. They give us an idea of the life of the primitive people. Rock paintings are found in these shelters. A total of 55 rock shelters have been identified in Pachmarhi Biosphere Reserve. Figures of animals and men fighting, hunting, dancing, and playing musical instruments are depicted in these paintings. Many tribals still live in the area.
As children move ahead, they see a board with ‘Satpura Tiger Reserve’ written on it. Madhavji explains that Project Tiger was launched by the government to protect the tigers in the country. The objective of this project was to ensure the survival and maintenance of the tiger population in the country.
Tiger (Fig. 7.4) is one of the many species which are slowly disappearing from our forests. But, the Satpura Tiger Reserve is unique in the sense that a significant increase in the population of tigers has been seen here. Once upon a time, animals like lions, elephants, wild buffaloes (Fig. 7.5) and barasingha (Fig. 7.6) were also found in the Satpura National Park. Animals whose numbers are diminishing to a level that they might face extinction are known as the endangered animals. Boojho is reminded of the dinosaurs which became extinct a long time ago. Survival of some animals has become difficult because of disturbances in their natural habitat.
Madhavji tells Paheli that small animals are much more in danger of becoming extinct than the bigger animals. At times, we kill snakes, frogs, lizards, bats and owls ruthlessly without realising their importance in the ecosystem. By killing them we are harming ourselves. They might be small in size but their role in the ecosystem cannot be ignored. They form part of food chains and food webs, about which you learnt in Class VII. An ecosystem is made of all the plants, animals and microorganisms in an area along with non-living components such as climate, soil, river deltas, etc.
7.9 Red Data Book Prof.
Ahmad explains about Red Data Book to the children. He tells them that Red Data Book is the source book which keeps a record of all the endangered animals and plants. Thereare different Red Data Books for plants, animals and other species. (For further details about Red Data Book, you can log on to www.wil.gov.in/envis/ primates/page102htm/new/nwdc/ plants.htm)
The excursion party then enters deeper into the forest under the guidance of Madhavji. They sit near the Tawa Reservoir to relax for some time. Paheli observes some of the birds near the river. Madhavji tells the children that these are the migratory birds. These birds have flown here from other parts of the world. Migratory birds fly to far away areas every year during a particular time because of climatic changes. They fly for laying eggs as the weather in their natural habitat becomes very cold and inhospitable. Birds who cover long distances to reach another land are known as the migratory birds as Paheli learnt in Class VII.
7.11 Recycling of Paper Prof.
Ahmad draws the attention of the children to another cause of deforestation. He tells them that it takes 17 full grown trees to make one tonne of paper. Therefore, we should save paper. Prof. Ahmad also tells that paper can be recycled five to seven times for use. If each student saves at least one sheet of paper in a day, we can save many trees in a year. We should save, reuse used paper and recycle it. By this we not only save trees but also save energy and water needed for manufacturing paper. Moreover, the amount of harmful chemicals used in paper making will also be reduced.
7.12 Reforestation Prof.
Ahmad suggests that the answer to deforestation is reforestation. Reforestation is restocking of the destroyed forests by planting new trees. The planted trees should generally be of the same species which were found in that forest. We should plant at least as many trees as we cut. Reforestation can take place naturally also. If the deforested area is left undisturbed, it reestablishes itself. In natural reforestation there is no role of human beings. We have already made a tremendous damage to our forests. If we have to retain our green wealth for generations, plantation of more trees is the only option. Prof. Ahmad told them that in India we have the Forest (Conservation) Act. This act is aimed at preservation and conservation of natural forests and meeting the basic needs of the people living in or near the forests. After some rest Madhavji asks children to start moving back because it is not advisable to stay back in the jungle after sunset. On getting back, Prof. Ahmad and the children thank Madhavji for guiding them through this exciting experience.
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
(c) Villages (Rural areas)
(d) Cities (Urban areas)
(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.
11. Complete the word puzzle:
1. Species on the verge of extinction.
2. A book carrying information about endangered species.
5. Consequence of deforestation.
1. Species which have vanished.
3. Species found only in a particular habitat.
4. Variety of plants, animals and microorganisms found in an area.
Extended Learning – Activities and Projects
1. Plant at least five different plants in your locality during this academic year and ensure their maintenance till they grow.
2. Promise yourself that this year you will gift at least 5 plants to your friends and
Extended Learning – Activities and Projects
1. Plant at least five different plants in your locality during this academic year and ensure their maintenance till they grow.
2. Promise yourself that this year you will gift at least 5 plants to your friends and relatives on their achievements, or on occasions like birthdays. Ask your friends to take proper care of these gifted plants and encourage them to gift five plants to their friends on such occasions. At the end of the year count the plants that have been gifted through this chain.
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