Living Science 2020 2021 Solutions for Class 8 Science Chapter 7 - Conservation Of Plants And Animals

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Flora of a region encompasses all the plants of a region and fauna refers to all the animals present in a region.

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'Variety of all forms of life present in a region' constitute the biodiversity of that region.

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Trees do not reduce groundwater by transpiration. Trees regulate water cycle by releasing the water through transpiration. This water condenses in the form of rain, which maintains the groundwater level. Moreover, tree also increase the absorption of rainwater by the soil, which maintains the water table.

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The cutting down of all trees in a place will have following effects on the land:

1. The rate of soil erosion will increase.

2. Continued soil erosion can lead to desertification.

3. The water absorbing capacity of soil will be decreased, which will effect the groundwater level.

4. The ecological balance of the place will be disturbed.

5. The local biodiversity will be severely depleted.

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Extinct species cannot be found on the Earth because all the members of these species have disappeared from the Earth. Some examples of extinct species are dinosaur and dodo.

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Planned harvesting is a method of forest conservation. In this method, some of the trees in an area are cut. The trees that are left uncut help in the prevention of soil erosion. Moreover, these trees also produce seeds, which allow the growth of new trees. Thus, planned harvesting of trees does not refer to the cutting down all trees in an area.

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The distribution of some species is restricted to a particular region. These species are defined as endemic species. The endemic species are primarily found in their natural habitat and these species are not naturally found outside their area of distribution. Thus, endemic species are not widely distributed throughout the Earth.

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Paper are obtained from the wood pulp. In order to obtain one ton of paper, approximately seventeen fully developed trees are required. Thus, saving paper will reduce the number of trees required for paper production and will help in conservation of forests.

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Red list and Red Data Book serve as tools for the assessment of conservation status of species around the world. These are useful in identifying the species that face the threat of extinction.

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(b) flora.
The plants of a particular region are called flora of that region.

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(c) endemic

Red data book has the following categories of conservation of species:
(i) extinct, (ii) extinct in wild, (iii) critically endangered, (iv) endangered, (v) vulnerable and (vi) rare. Thus, it does not have a record of endemic species.

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(d) storms
Deforestation is removal or deterioration of forest cover of an area. It leads to the following consequences:
(i) desertification (due to decrease in amount and periodicity of rainfall)
(ii) global warming (due to increase in atmospheric carbon dioxide concentration)
(iii) groundwater level depletion  

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(b) extinct species
Dodo is an example of extinct species, as it has been eliminated from the earth.

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(d) Red Data Book
Red Data Book is a compilation of data on various categories of endangered plants and animals.

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(a) wildlife conservation

WWF stands for World Wide Fund for nature. It works in the field of wildlife conservation.

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(c) dodo
Dodo is an extinct species.

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(b) Asiatic lion

Asiatic lion is an endangered species. All the other options are examples of extinct species.

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Biodiversity of an area refers to the vast number of species of plants, animals and microorganisms existing in that area.

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Fauna refers to animals, whereas flora refers to plants.

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Yes, I agree with the statement. Forests provide plant cover to check the flow of water. If forests are removed, then floods will occur.

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False.

Endangered animals are those species whose numbers are diminishing at an alarming rate and face an immediate danger of extinction.

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If all trees in a forest are cut, it will lead to erosion of soil.

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Grazing by cattle should be controlled for forest conservation.

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True.
Soil erosion is the removal of top layer of soil that is most fertile. If not checked, soil erosion ultimately leads to desertification.

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The flora and fauna of a country are among the most important renewable natural resources.

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Dinosaurs are extinct because no living member of this species is present on earth.

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Wildlife conservation and forest conservation are closely related.

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False.
A biosphere reserve comprises of three core areas: natural zone, buffer zone and transition zone. These zones are not present in a tiger reserve.

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Saving paper means saving trees.

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Species that are confined to a restricted area on the earth are known as endemic species.

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The Red List is a list of endangered animals.

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Biodiversity is the term describing the variety of life on earth, including plants and animals. It reflects the number, variability and variety of living organisms and how these change from one location to another over a period of time.

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The plant life of an area or a region is termed as flora.
The animal life of an area is termed as fauna.

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The cutting of forests and using that land for other purposes is called deforestation. Deforestation takes place due to an increased demand for wood and land for constructing factories, houses, roads and dams.

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Some animals become endangered because their population is already low. Also activities such as illegal hunting and deforestation further reduces their natural population.

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A biosphere reserve is a protected area meant for the conservation of plant and animal life. A biosphere reserve also provides awareness about the environment and eco-friendly living.

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Endemic species are those species of plants and animals that are found in a specific geographical area and no other place. Example: Wild mango and giant squirrel are endemic species of Pachmarhi.

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IUCN prepared the Red Data Book because it  keeps a record of all endangered animals and plants. Through this book, IUCN is trying to create awareness about the endangered species.

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The species listed in the Red List and Red Data Book are classified into the following categories:
(a) Extinct
(b) Extinct in wild
(c) Critically endangered
(d) Endangered
(e) Vulnerable
(f) Lower risk
(g) Rare species

Answer:

Forests are useful to us in following ways:
(a) All the food we eat comes from plants and animals which are an essential component of forests.
(b) Forests regulate global climate.
(c) Wood used as timber in construction and furniture works comes from trees in the forests.
(d) Forest cover is essential for retention of rainwater.

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Following are the three main causes of deforestation:
(a) Overgrazing: The cattle graze in forests tramples seedling and causes compaction of soil.
(b) Forests fire: It is a natural cause. Forest fires in the past have destroyed a vast area of forest in Indonesia.
(c) Hydroelectric projects: Construction of dams for hydroelectric projects submerge forest tracts, killing all plants and animals.

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Deforestation causes soil erosion. Removal of top layer of soil exposes the lower, hard layers of soil. This soil has less humus and is less fertile. Gradually, the fertile land gets converted into deserts. This is called desertification. Hence, 'deforestation can lead to desertification'.

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Deforestation leads to the depletion of water table. The trees help in prevention of running of water by allowing the soil to absorb the flowing water. This water percolates down and groundwater level rises. However, when trees are cut, water runs off quickly as soil is unable to absorb the flowing water. Thus, water does not percolate down and groundwater level depletes.

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Planned harvesting of forests means sustainable use of forest products with the involvement of local community. The local community helps in conserving the forests by not cutting the trees. Instead, more trees are planted by the joint efforts of government and local community. It is popularly known as Joint Forest Management.

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Wildlife depends on forest for food and shelter. So, forest conservation is directly related to wildlife conservation. If the forest of an area is conserved, then the wildlife of the same area also gets protected as they get plenty of food and proper shelter.

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Following are the five methods of forest conservation:

(a) Reforestation:
It is the act of planting more trees to replace the cut trees.
(b) Discouraging killing of animals:
People should not buy any item made from animal skins such as horns and feathers.
(c) Conservation programmes:
Some organisations help in conservation of forests through their projects, programmes and joint efforts with the government.
(d) Reduce, reuse and recycle:
By reducing our usage of paper, we can conserve many trees in a year. Paper can also be reused and recycled. By doing this, we conserve our forests.
(e) Laws to conserve forests:
Legal act such as The Forest (Conservation) Act passed by the Government of India aims at preserving and conserving natural forests and meeting the needs of people living near the forests.

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The consequences of deforestation are as follows:

(a) Deforestation reduces rainfall:
Due to deforesting, level of carbon dioxide in the environment increases, which, in turn, increases the earth's temperature.
(b) Danger to wildlife:
Forests are natural habitat of wildlife. Due to deforestation, natural habitats get destroyed and face extreme danger.
(c) Rise in temperature:
Due to increased amount of carbon dioxide in the environment, temperature of the earth increases.
(d) Increased soil erosion:
Soil gets exposed due to deforestation and loses its fertility.

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The various steps necessary for wildlife conservation are as follows:

(a) All the known endangered species should be protected.
(b) Feeding places of migratory birds should be identified and protected.
(c) Wildlife conservation laws should be enacted and should meet out strict punishment to anyone violating these laws.
(d) Wild relatives of all the economically important organisms should be identified and conserved in protected areas.

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I do not agree with the statement. To conserve forests, we should prefer sustainable forest management. It means that if we cut one tree, then we must plant four new trees. In this way, we can conserve forests for our future generations. Active participation of local community living near the forest is also essential.

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The construction company will not be able to maintain the number of trees in the forests. As there are various factors that decide the growth of sapling into a tree, it is not necessary that every sapling will grow into a complete tree. Hence, the company should plant five saplings for every tree cut.

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It is not fair to prevent the entry of tribals into forests. Instead, tribals should be educated about the various beneficial aspects of forests. Also, government should involve tribals in conserving the forests through active participation in programmes such as Joint Forest Management. In this way, tribals would get the resources for their daily living and in turn forests would also be conserved.

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Yes, it is true that by protecting the tigers, we protect all other forms of flora and fauna. Tigers are known as umbrella species. It is a term used for species whose conservation and protection would indirectly lead to the conservation of other species of flora and fauna.
Protecting the tiger means the flora and fauna of that region also gets protection and conservation.

No, a tremendous increase in the tiger population is not desirable. A tremendous increase in the population of tigers means, the food chain gets disturbed and poses a threat to the existence of other animals.

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From the above scenario, we can say that Salma is a caring and loving girl. She cares about the birds and thus provides them with food and shelter.