Class 8 Science Textbook Solution

Conservation of Plants and Animals – Class 8 Science Textbook Solution


Class 8 Science Chapter 6 Conservation of Plants and Animals
 
1. Fill in the blanks.
1.    A place where animals are protected in their natural habitat is called __________
2.    Species found only in a particular area is known as __________
3.    Migratory birds fly too far away places because of __________ changes.
Answer:

1.    biosphere reserves
2.    endemic
3.    climatic
 
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
Answer:
   
 
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
Answer:

(a) Deforestation will lead to a decrease in the population of wild animals. The wild animals will die when they will have no food to eat and a place to live. Some wild animals may come to the cities where they will be killed by human beings.
9.    (b) Deforestation will affect the environment very badly. There will be an increase in the amount of carbon dioxide due to fewer plants. This will increase the temperature of the atmosphere. Rainfall will be reduced. Soil fertility would decrease.
10.    (c) Villages (Rural areas) will be destroyed by deforestation because villagers depend upon forests for their daily needs. They get fruits, nuts, medicines, gum, resins, timber, etc. from forests.
(d) Cities (Urban areas) will also be affected by deforestation. There will be more floods and soil erosion. The water level will decrease. The amount of CO will increase. Pollution will increase. The development of cities will stop due to less availability of timber and paper etc.
(e) Earth will be drastically affected by deforestation. Life will slowly get extinct if pollution and C02 keep on increasing. There will be no rainfall. The water level will fall. There will be floods and droughts. The temperature will rise. Soil fertility will be reduced.
(f) The next generation will also be effected by deforestation because there will be a scarcity of water and pure air. There would be no wood for building houses, furniture, and factories. There will be no paper, medicines, fruits, nuts, gum, resins, and other useful products.
 
4. What will happen if:
1.    we go on cutting trees;
2.    the habitat of an animal is disturbed;
3.    the top layer of soil is exposed.
Answer:

1.    If we go on cutting trees deforestation will happen.
2.    If the habitat of an animal is disturbed then that animal may be extinct.
3.    If the top layer of the soil is exposed that desertification will happen.
 
5. Answer in brief:
(а) Why should we conserve biodiversity?
(b) Protected forests are also not completely safe for wild animals. Why?
(c) Some tribes 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?
Answer:

(a) We should conserve biodiversity because preserving areas of such biological importance make them a part of our national heritage.
(b) Protected forests are also not completely safe for wild animals because people living around kill the animals for leather etc. The cutting of trees also effects wild animals.
(c) Some tribes depend on the jungle for food, medicines, fruits, gum, etc. Their cattle feed in these jungles. They get wood and bamboo for building then huts from these jungles.
(d) Causes of deforestation are:
•    cutting trees for procuring land for cultivation,
•    cutting trees for building houses and factories,
•    cutting trees for making furniture,
•    cutting trees for fuel.
Consequences of deforestation are:
•    it increases the temperature and pollution level on the earth.
•    it decreases the level of oxygen in the atmosphere.
•    it lowers the groundwater level.
•    it decreases rainfall and the fertility of the soil.
•    it increases the chances of natural calamities such as floods and drought.
(e) Red Data Book is the sourcebook which keeps a record of all endangered animals and plants.
(f) Migration is the phenomenon of movement of a species from its own habitat to some other habitat for a particular time period every year for a specific purpose like breeding.
 
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 this in your class and prepare a brief report.
Answer:
It is not justified to cut trees for projects instead we should use those sources which are renewable. In case it becomes essential to cut trees than for every single tree cut, two trees should be planted in a planned manner. But, if trees are cut blindly and not trees are planted then the earth will face global warming, no rainfall, climatic change, soil erosion, and desertification, etc. So, cutting trees for any reason at all is not justified.
 
7. How can you contribute to the maintenance of the green wealth of your locality? Discuss in your class and make a list of actions to be taken by you.
Answer:
The actions taken by us to maintain a green wealth of our locality will be:
•    We should protect the plants in our locality from insects, pests, and diseases by using suitable pesticides and fungicides.
•    Plants should be planted in areas which are barren.
•    A club should be formed, which should take care of plants. Money should be collected from the residents and gardeners should be appointed to take care of plants.
•    Senior citizens should be involved to take care of plants.
•    Children should be taught the importance of plants.
 
8. How does deforestation lead to reduced rainfall? Discuss in your class and find out the causes.
Answer: The causes of reduced rainfall are:
•    Deforestation causes soil erosion. Due to this soil becomes barren and incapable of retaining water. This reduces rainfall.
•    Plants need carbon dioxide for photosynthesis. Fewer trees would mean less consumption of carbon dioxide and its increased amount in the atmosphere. This leads to global warming as carbon dioxide traps the heat of sun rays. The increase in temperature on earth disturbs the water cycle and reduces rainfall.
 
9. Find out about national parts in your state. Identify and show their location on the outline map of India. 
Answer: See Map

10. Think about the need of saving paper. Discuss with your friends, parents, and teachers. Prepare a list of the ways by which you can save paper.
Answer:
The ways by which we can save paper are:
•    Use the blank side of the paper that has already been written or printed on for rough work.
•    If the same product is available in the same quantity in different paper packets we should choose the one in the smallest paper packet.
•    We should not throw paper but instead, it should be recycled.
•    We should use recycled paper.
•    Instead of letters, we should use e-mails.
•    We use reuse paper.
 
11. Complete the word puzzle:
Down
1. Species on the verge of extinction.
2. A book carrying information about extinct species.
5. Consequence of deforestation.
Across
1. Species which have vanished.
3. Species found only in a particular habitat.
4. Variety and variability of a plant, animal, and micro-organsims.
Answer:

 
Conservation of Plants and Animals Additional s and Answers
 
1. What is meant by deforestation?
Answer:
Deforestation means clearing of forest and using that land for other purposes.
 
2. Write two natural causes of deforestation.
Answer
: Two natural causes of deforestation are:
(i) Forest fires
(ii) Severe drought.
 
3. What is desertification?
Answer:
Desertification is the conversion of fertile land into deserts.
 
4. How are the properties of the soil changed by deforestation?
Answer:
The physical properties of the soil get affected by the plantation and vegetation of that area. Fewer trees result in more soil erosion. Removal of the top layer of soil exposes the lower hard and rocky layers This soil has less humus and is less fertile. The water holding capacity of soil and movement of water from the soil surface into the ground is decreased.
 
5. What are the names given to the protected and conserved areas which save forests and wildlife?
Answer:
Wildlife sanctuaries, national parks, biosphere reserves, etc. are names given to the protected and conserved areas which save forests and wildlife.
 
6. What are biosphere reserves? How does it help?
Answer:
Biosphere reserves are the areas meant for the conservation of biodiversity. The biosphere reserves help to maintain the biodiversity and culture of that area.
 
7. What do you mean by the terms
(i) Flora
(ii) Fauna?
Answer:

(i) Flora: The term flora is used for all types of plant species, including wild and domesticated, living in a natural habitat of an area, a region, a Pradesh, or a country.
(ii) Fauna: The term fauna is used for all types of animals, including both wild and domesticated animals, living in a natural habitat of an area, a region, a Pradesh, or a country.
 
8. What are endemic species?
Answer:
Endemic species are exclusively found in a particular area only. They are not naturally found anywhere else. This area may be any geographical unit like a state, zone or a country, or habitat type.
 
9. What is meant by species?
Answer:
A species is a group of populations which are capable of interbreeding with each other.
 
10. What are wildlife sanctuaries?
Answer:
Wildlife sanctuaries are some areas where wild animals are protected and preserved. These are places where killing (poaching) capturing of any animal is strictly prohibited. They provide protection and suitable living conditions to wild animals.
 
11. What are national parks?
Answer:
National parks are reserves which are large and diverse enough to protect whole sets of ecosystems. They preserve flora, fauna, landscape, and historical objects of an area e.g. is Satpura National park. 
 
12. What is ‘Satpura Tiger Reserve’
Answer:
‘Satpura Tiger Reserve’ is a rescue to protect tigers.
 
13. What is reforestation?
Answer:
Reforestation is the restocking of the destroyed forests by planting new trees. The planted trees should be generally of the same species which existed in that forest.
 
14. How can reforestation take place naturally?
Answer:
Reforestation can take place naturally if the deforested area is left undisturbed.

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