NCERT Solutions for Class 8 Science Chapter 7 Conservation of Plants and Animals

Ans : (a) A place where animals are protected in their natural habitat is called  sanctuary 
(b) Species found only in a particular area are known as  endemic  
(c) Migratory birds fly to far away places because of  climatic  changes. 

Ans : (a)

(b) 

(c)

(d)
 

Ans : (a) Effects of deforestation on wild animals:
Deforestation is the removal of trees or other vegetation from an area for industrial, 
agricultural, or other purposes. Trees and other vegetation form the habitat of many animals. Hence, if the habitat of wild animals is destroyed, then their numbers would automatically decline. 
(b) Effects of deforestation on the environment: 
Plants absorb C02 from the atmosphere to perform photosynthesis. If plants are destroyed, then the level of C02 in the atmosphere will rise. As a result, C02 will trap more heat radiations, thereby adding to global warming. An increase in the temperature of the Earth will disturb the natural water cycle. As a result, there will be a change in the rainfall pattern. This could lead to floods or droughts. 
(c) Effects of deforestation on villages: 
Roots of plants hold soil particles together. In the absence of plants, the top layer of the soil will be easily removed by the action of high speed winds or water flow. Thus, deforestation increases the chances of soil erosion. As a result, soil loses humus and become less fertile. Hence, a fertile land, which is a source of living for farmers in villages, gets converted into a desert. 
(d) Effects of deforestation on cities: 
Deforestation in cities can increase the risk of many natural calamities such as floods 
and droughts in that area. Also, it can lead to global warming due to an increase in 
the level of C02 in the atmosphere as a result of vehicular and industrial pollution. 
This increase in temperature can disturb the natural water cycle of an area 
(e) Effects of deforestation on the Earth: 
As a result of deforestation, chances of desertification, droughts, floods, etc. increase. 
Deforestation can also increase the level of C02 in the Earth. It will lead to an increase in temperature i.e., global warming. As a result, the entire natural water cycle will get disrupted. This again increases the risk of natural calamities.
(f) Effects of deforestation on the next generation:
Deforestation is slowly changing our environmental conditions. It is responsible for global warming, soil erosion, greenhouse effect, drought, floods, and many other global problems. As a result, the next generation will have to face severe consequences of deforestation. 

Ans : (a) If we go on cutting trees, the natural habitat of many animals will get completely destroyed. As a result, the biodiversity of many areas will be severely affected. Also, there will be an increase in the temperature of the Earth as a result of global warming, which can disturb the natural water cycle. As a result, there will be a change in the rainfall pattern. This could lead to floods or droughts. This will also increase the risk of soil erosion, desertification, and natural calamities. 
(b) The habitat of an animal provides it with necessities such as shelter, food, and protection. If the habitat of an animal is disturbed, then it will be forced to go to other places in search of food and shelter. The animal could get killed by other animals in this process. 
(c) If the top layer of soil is exposed, then it will gradually expose the lower layer of soil, which is hard and rocky in nature. This type of soil is less fertile as it contains less humus. Continued soil erosion will make the land barren or infertile. 

Ans : (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) Tribals gather food, fodder, and fallen branches of trees from forests. Hence, they depend on forests for their daily requirements. 
(d) Causes of deforestation: 
(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 source book that maintains an international list of all endangered 
animal and plant species. This book is maintained by II-JCN (International Union for 
Conservation of Nature and Natural resources).
(e) Red Data Book is a source book that maintains an international list of all endangered 
animal and plant species. This book is maintained by II-JCN (International Union for 
Conservation of Nature and Natural resources).
(f) Migration refers to the movement of an organism or a group of organisms from its natural habitat to another place at a particular time every year. Organisms migrate from one place to another to avoid inhabitable climatic conditions or for breeding.