NCERT Solutions for Class 8th Science
Chapter 7. Conservation of Plants And Animals
Text Book Exercise
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.
(a) wildlife sanctuary
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.
(a) Differance between wildlife sanctuary and biosphere reserve :
(i) This is an area where wild animals are protected and preserved.
(ii) Wildlife sanctuary is a place found in biosphere reserves.
(iii) Bori and Panchmarci are two wildlife sanctuaries in Panchmarhi biosphere.
(i) It helps to maintain the biodiversity and culture of the area.
(ii) A biosphere reserve may also contain other protected areas like wildlife sanctuary.
(iii) Panchmarhi, for example, is a biosphere reserve.
(b) Differnces betweeen zoo and wildlife sanctuary :
(i) It is a place where we protect animal.
(ii) Here artificial surroundings are made for animal in place of natural habitas.
(iii) Here animal are suppplied prepared fod here.
(i) Here, too, wild animal are preserved.
(ii) They live in their natural habitats.
(iii) They get their food from from forests (sanctuaries) them selvs. the food is fresh.
(c) Differences between endangered and extinct species :
(i) These are those species which are facing the danger of extinction.
(ii) Tiger is an example of an endangered species.
(i) They ae the species which have already vanished from earth.
(ii) Dinosaurs is an example of extinct species.
(d) Differences between flora and fauna :
(i) Flora are the plants found in a particular region.
(ii) Sal, teak, mango, jamun, silver ferns, arjun, etc. are the example, of flora.
(i) Fauna are the plants animals found in a particular region.
(ii) chinkara, blue-bull, barking deer, cheetal, leopard, wild dog and wolf are the examples of fauna.
3. Discuss the effects of defotation on the following:
(a) Wild animals
(c) Villages (Rural areas)
(d) Cities (Urban areas)
(f) The next generation
Answer : (a) Wild animals :
They won,t get their natural habitat and surroundings, as well as food. So either they will extinct or reach at the verge of extinction or they will migrate to another forest. In course of their migration, they might be killed by humans.
(b) Environment :
Climatic changes disturb the ennvironment. Global warming is causeddue to accumulation of carbon dioxide. Because of caused due to accumulation of carbon dioxide. Because of deforestation and increase in the tempreture on earth, watercycle will get disturbed and the reduced rainfall will cause droughts.
(c) Villages (rural area) :
Villlagere cannot grow food (crops) because of no rain. So drought situations will prevail. Many poor villagers may die for want of food. The villagers will move to towns and cities and villlages will be completely deserted.
(d) Cities :
Cities flooded with drought-affected villagers, will disturb the environment. Food-grains will eiter not available, they will be costlier. The people will also not get wood for making furnitures and buildings.
(e) Earth :
Deforestation is a major cause which leads to change in the soil properties. Physical properties of the soil will get affected badly. Soil erosion caused due to floods will remove the top layer of soil.The remaining part of soil will have less humas and thus less fertile. Gradually the land will get converted into desert. In the other hand the snow of the mountains will melt due to the global warming, and many cities will be flooded causing disastour.
(f) The next generation :
The next generation will either be extinct or if at all it exists, they will suffer from diseases and face life without food. So, the next generation will be ill, weak and, consequently, face extinction.
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.
Answer: (a) If we go on cutting trees, then following situation will arrive (i) The climatic change will affect the enviroment due to global warming and no there will be rain.
(ii) The soil will became unfertile due to reagular flooding of top soil. Consequently the land will become desert.
(b) If the habitat of an animal is disturbed, the animal may not be in position of getting its natural habitat as well as food. So, in the long run, the animal will face extinction.
(c) Removal of top layer of soi by floods and heavy winds will expose the lower hard and rockey layers. This oil has less humus and less fertility. So, grandually the fertile land will be converted into desert.
5. Answer in brief:
(a) Why should we conserve biodiversity?
Answer : If the biodiversity is not conserved, the life existing on earth, their interrelationships and their relationshipes with the enviroment will be disturbed, which will affect the lives on earth adversely.
(b) Protected forests are also not completely safe for wild animals. Why?
Answer : It is because despite all these the poachers keep killing or capturing the animals in these forests.That is why protected forests are also not completely safe for wild animals.
(c) Some tribals depend on the jungle. How?
Answer : some tribals live in the jungle. Jungle provides them food and protection. That is why, they are fully depended upon the forest.
(d) What are the causes and consequences of deforestation?
Answer : Causes of deforestation :
(i) Procuring land for cultivation. (ii) Building housesand factories.
(iii) Making furniture or usig wood as fuel. (iv) Some natural causes like forest fire and severe drought.
Consequences of deforestation : (i) Global warming which disturbs the water cycle and reduces rainfall. Ultimately, drought is caused. (ii) Soil erosion and desertification of land due to frequent floods. (iii) Melting of snow on the poles, which causes flooding of seas and oceans causing destruction of cities and towns by the sides of seas and oceans.
(e) What is Red Data Book?
Answer : Red Data Book is the source book which keeps a record of all endangered animals and plants.
(f) What do you understand by the term migration?
Answer : Migration is the phenomenon of movement of species from its own habitat to some other habitat to some other habitat for particular time period every year for change of climate and for the purpose of breeding.