Goa Board Class 8 Solutions for Science – Conservation of Plants and Animals (English Medium)
Page No. 86:
Fill in the blanks:
(a) A place where animals are protected in their natural habitat is called a __________ .
(b) Species found only in a particular area are known as ___________.
(c) Migratory birds fly to far away places because of ____________ changes.
Concept insight: Important from Exam Point of View.
|Wildlife sanctuary||Biosphere reserve|
|(i) It is an area within which animals are protected from possible dangers such as hunting. Their habitat is also conserved in this area.||(i) It is a large protected area constructed for the conservation of biodiversity.|
|(ii) It provides protection and suitable living conditions to wild animals.||(ii) It helps in the conservation of various life forms such as plants, animals, and micro- organisms.|
|(iii) Pachmarhi sanctuary is a wildlife sanctuary.||(iii) Pachmarhi biosphere reserve is a popular biosphere reserve.|
Concept insight: List the differences between wildlife sanctuary and biosphere reserve.
|Zoo||Wild life sanctuary|
|(i) It is a facility in which animals are kept for public exhibition.||(i) It is an area within which animals are protected from possible dangers such as hunting. Their habitat is also conserved in this area.|
|(ii) It is an artificial habitat.||(ii) It conserves the natural habitat of animals.|
Concept insight: List the differences between zoo and wildlife sanctuary.
|Endangered species||Extinct species|
|(i) It is a population of species that is on the verge of becominq extinct.||(i) It is a population of species that no longer exists, Hence it is extinct.|
|(ii) Blue whale, tiger, leopard, etc. are examples of endangered species.||(ii) Dodo, passenger pigeon, etc. are examples of extinct species.|
Concept insight: List the differences between endangered and extinct species.
|(i) It refers to all living plants in a particular area.||(i) It refers to all animals living in a particular area.|
|(ii) Sal, teak, mango, etc. form the flora of Pachmarhi biosphere reserve.||(ii) Leopard, wolf, wild dog, etc. form the fauna of Pachmarhi biosphere reserve.|
Concept insight: List the differences between flora and fauna.
Discuss the effects of deforestation on the following.
(a) Wild animals
(c) Villages (Rural areas)
(d) Cities (Urban areas)
(f) The next generation
(a) Effects of deforestation on wild animals: Due to deforestation forests are vanishing due to which animals are loosing their natural habitat. Therefore their population is declining rapidly.
Concept insight: Deforestation leads to the loss of habitat of wild animals.
(b) Effects of deforestation on the environment:
- Balance of carbon dioxide and oxygen has been disturbed.
- It has also changed rainfall distribution at many places.
- Due to it amount of carbon dioxide has increased in environment due to which global warming has increased.
Concept insight: Deforestation leads to global warming and thus affects environment.
(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 becomes less fertile. Hence, a fertile land gets converted into a desert.
Concept insight: Due to deforestation soil erosion has increased and soil is loosing its fertility.
(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 CO2 in the atmosphere as a result of vehicular and industrial pollution. This increase in temperature can disturb the natural water cycle of an area.
Concept insight: Deforestation has increased global warming.
(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 CO2 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.
Concept insight: Deforestation has disturbed the ecological balance.
(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.
Concept insight: Deforestation has many effects on ecosystem and leads to global problems.
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.
(a) If we go on cutting trees, the natural habitat of many animals will get completely destroyed. it will have the following consequences.
- Ecological balance will be disturbed.
- 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. This will ultimately become a major threat to the biodiversity of earth.
(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.
Concept insight: List the consequences of deforestation.
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?
(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.
Concept insight: Biodiversity also maintains ecological balance which is necessary for our survival.
(b) Protected forests are not completely safe for wild animals because people who live near or adjacent to forests use resources from forests to fulfill their own requirements. In this process, wild animals are killed and sold for lucrative amounts of money.
Concept insight: Animal poaching is done and government takes no action against poachers.
(c) Some tribals are dependent on forests as they provide them shelter, food, etc. They also collect wood and herbs from forests.
Concept insight: Recall the concept of conservation of forests.
(d) Causes of deforestation:
- Forests are cleared for accommodating expanding urban areas and for fulfilling their ever-increasing requirements.
- Forests are destroyed to clear land for crops and cattle grazing.
- Trees are cut down to be used for firewood.
Consequences of deforestation:
- Soil erosion
- Loss of biodiversity
- Floods and droughts
- Climate changes due to global warming
- Disruption of water cycle
Concept insight: List the factors that leads to deforestation and its consequences.
(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 IUCN (International Union for Conservation of Nature and Natural resources).
Concept insight: Red Data Book maintains the account of endangered animal and plant species.
(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.
Concept insight: Migratory birds fly to far away area every year during a particular time because of climatic changes.
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.
No. It is not at all justified to cut trees to meet the ever increasing demands of human population. Forests are the habitat of several organisms including wild animals. They provide us with good quality air as they give out O2 and absorb the harmful CO2 gas from the atmosphere.
In this process, they prevent the excessive heating of the atmosphere. They prevent soil erosion and natural calamities such as floods and droughts. They increase the fertility of the soil and help to conserve biodiversity. The cutting of forests to meet the demands of growing human population will lead to global warming, soil erosion, greenhouse effect, droughts, floods, and many more problems. The destruction of forests will disturb the balance of nature. Hence, forests must be conserved.
Concept insight: If all the forests got destructed we will also not be able to survive.
How can you contribute to the maintenance of green wealth of your locality? Make a list of actions to be taken by you.
Following steps can be taken to maintain green wealth of our locality:
- I can help in maintaining the green wealth of my locality by taking care of the plants and trees growing in or around my locality. I can plant more and more number of trees.
- I can also encourage the people in my locality to plant more trees by informing them about the importance of growing trees.
- I can make young children aware of the effects of deforestation and its effect on our environment and on our planet.
- I can also ask them to water the plants daily which will take very little of their time. I believe planting new trees is as important as taking care of the existing trees.
Concept insight: List the importance of flora.
Explain how deforestation leads to reduced rainfall.
Deforestation is the removal of trees or other vegetation from an area for industrial, agricultural, or other purposes. Plants or trees absorb CO2from the atmosphere. If plants are destroyed, then the level of CO2 in the atmosphere will rise. The high levels of CO2 in the atmosphere will trap more heat radiations, leading to global warming. This increase in temperature of the Earth will disturb the natural water cycle. As a result of disruption in the water cycle, there will be a change in the rainfall pattern. The reduced amount of rainwater can cause droughts.
Concept insight: Large amount of water vapours are added by forests in atmosphere by transpiration. Increasing global warming has disturbed rainfall patterns.
Find out about national parks in you state. Identify and show their location on the outline map of India.
An area strictly reserved to perserve flora, fauna, landscapes and historic objects existing in the area is callec a national par. One of the nation parks located near Delhi is the Corbett Nation Park.
Why should paper be saved? Prepare a list of ways by which you can save paper.
Paper should be saved because it takes around seventeen full grown trees to make one tonne of paper. Trees, as we know, are important to maintain a balance of nature. Therefore, in order to save trees and prevent the impact of their loss on living organisms, we need to save paper.
Ways by which paper can be saved:
- Collect the used paper and recycle it.
- Use both sides of a paper for writing.
- Spread awareness about the importance of paper.
- Use paper intelligently.
Concept insight: Trees are necessary for our survival as they provide food, oxygen and maintain water cycle.