NCERT solutions for class 8 Science Chapter 7 Conservation Of Plant And Animals

Solution for Exercise

Q.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 faraway places because of __________ changes.


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Answer :

(a) A place where animals are protected in their natural habitat is called __Sanctuary__.
(b) Species found only in a particular area is known as __endemic__.
(c) Migratory birds fly to faraway places because of __climatic__ changes.

Q.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


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Answer :

(a)
Wild life sanctuary
An area in which wild animals are protected from external danger like hunters. Ex - corbate national park
Biosphere resurve
An area constructed for the conservation of biodiversity ex-nilgiri biosphere resurve
(b)
Zoo
(i)A place where animals are protected in an artificial habitat, for an exhibition.
(ii) it is an artificial habitat
Wild life sanctuary
(i)An area in which wild animals are protected from external danger like hunters.
(ii) it is a natural habitat.
(c)
Endangered species
The species which are on the verge of extinction are called as Endangered species. Eg: tigers, dolphins, blue whales
Extinct species
The species of animals whose number is zero because of changes in their habitat and other calamities. Eg: Caribbean monk seal, Great Auk, Passenger pigeon.

Q.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


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Answer :

(a) Effects of deforestation on wild animals:
Removal of trees and plant life from a particular area for the construction of industries, agriculture or for other such purposes is termed as Deforestation. Plantlife forms an integral part of the ecosystem and these plants form the natural habitat of various animals of that ecosystem. Destroying the plant life will ultimately threaten the existence of animals in that particular ecosystem and may lead to their extinction.
(b) Environment: Deforestation increases the temperature and pollution level of the environment. With the increase in the carbon dioxide level and a decrease in the oxygen level, it gives rise to global warming. It also lowers the level of ground water. Moreover, deforestation decreases the soil fertility and so, increases the chances of natural calamities
(c) Villages (Rural areas): The decline in rainfall, the decrease in soil fertility, and the chances of natural disaster affect the village life.
(d) Cities (Urban areas): Deforestation result in global warming. It also results in the increase in the level of pollution. Hence, deforestation affects the life in cities.
(e) Earth: Deforestation decreases the fertility of soil. It changes the physical properties of soil. All these changes result in desertification.
(f) The next generation: Deforestation will majorly affect the life of next generation. The next generation will face problems at every step. Climatic conditions will be adversely affected. There will be scarcity of food and clean environment. Next generation won’t be able to see most of the animal species due to habitat loss.

Q.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


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Answer :

(a)
if we go on cutting trees then
The temperature will increase to greater extent.
animals loss their habitat . It causes green house effect . And increase global warming. the water cycle will get disturbed.
(b)
If the habitat of an animal is distrubed then
the animals will lose their natural habitat and will reach the level of being endangered.
All the basic necessities for an animal, like food, water, shelter and protection is provided by the habitat in which the animal lives-in disturbing the habitat of the animal forces it to move to another place in search of food, water, shelter and protection.
(c)
the top layer of soil is exposed then
the exposed layer will lose all its nutrients, especially the hummus. the water holding capacity of soil will decrease.

Q.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?


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Answer :

(a)
Biodiversity refers to the number and variety of various life forms such as plants, animals, and micro-organisms in an area. Plants and animals depend on each other for survival. This means that the destruction of either of the two will affect the life of the other. Hence, we need to conserve biodiversity to maintain the balance of nature.
(b)
Protected forests are not completely safe for wild animals because people who live near or adjacent to forests use resources from forests to fulfil their own requirements. In this process, wild animals are killed and sold for lucrative amounts of money.
(c)
The forests provide food, fodder and other resources to the tribal people. It is inevitable for them to depend on forests and their resources for everyday needs.
(d)
(i) Forests are cleared for accommodating expanding urban areas and for fulfilling their ever-increasing requirements.
(ii) Forests are destroyed to clear land for crops and cattle grazing.
(iii) Trees are cut down to be used for firewood.

Consequences of deforestation:
(i) Soil erosion
(ii) Loss of biodiversity
(iii) Floods and droughts
(iv) Climate change due to global warming
(v) Disruption of water cycle
(e)
Red Data Book is a sourcebook which keeps records of all endangered plants and animals.
(f)
Migration means the movement of a species from its own habitat to some other place during a certain period in a year for breeding or to overcome some climatic conditions.

Q.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.


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Answer :

It’s not justified to cut trees just to fulfill our needs. Trees are known as ‘the lung of the earth’. They are the habitat of many living organisms, including animals. They give us oxygen, and maintain the O2-CO2balance as well. They firmly bind the soil and hence prevent soil erosion. They also reduce the chances of natural disasters like floods and droughts. They help conserve our rich biodiversity. The cutting of trees causes an increase in the carbon dioxide (CO2) level, which results in global warming. Moreover, it causes soil erosion, floods, the greenhouse effect, etc. Hence, trees must be protected.

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


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Answer :

I can take care of the green cover of my locality by growing plants in my locality. I shall motivate the people of my neighbourhood to plant more trees and take care of the existing trees by creating awareness about the importance of plant life in an ecosystem. In order to make this possible, I would initiate the proceedings and organize weekly events on the same. Creating awareness among the children and youth would be of top priority as they will easily understand the issues that we are facing. Planting new trees is as important as looking after the existing ones. So, my volunteers and I would water the plants and trees on a regular basis.

Q.8 Explain how deforestation leads to reduced rainfall


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Answer :

Trees give out a huge amount of water in the form of water vapour during transpiration. The reduction of water vapour affects cloud formation and thus, results in less rainfall.

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


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Answer :

One of the national parks located near Delhi is the Corbett National Park

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


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Answer :

A large number of trees can be saved by saving paper. This will also save water that is used to manufacture paper. Moreover, the harmful chemicals used in papermaking will show their least effects on human beings and other organisms. Some ways to save paper are the following:
(a) recycling of paper.
(b) economical use of paper.
(c) paper should not be burnt.

Q.11 Complete the world puzzle.

Down

1. Species on the verge of extinction.
2. A book carrying information about endangered species.
5. Consequence of deforestation.

across

1. Species which have vanished.
2. Species found only in a particular habitat.
3. Variety of plants, animals and microorganisms found in an area.


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Answer :

Down

Endangered
Red Data Book
Deserts

Across

Extinct
Endemic
Biodiversity



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