Samacheer Kalvi 8th Science Solutions Chapter 22 Pdf

Samacheer Kalvi 8th Science Solutions Chapter 22 Pdf

Tamilnadu Board Samacheer Kalvi 8th Science Solutions Chapter 22: Tamilnadu State Board Solution Class 8 Science Chapter 22 – Conservation of Plants and Animals.

Samacheer Kalvi 8th Science Solutions Chapter 22: Overview

Board

Samacheer Kalvi
Class

8

Subject

Science
Chapter

22

Chapter Name

Conservation of Plants and Animals


Samacheer Kalvi 8th Science Solutions Chapter 22 Pdf

(I) Choose the best answer.

( 1 ) The plants found in a particular area are known as endemic.

(a) fauna

(b) flora

(c ) endemic       

(d) rare

(2) Deforestation means cleaning of forest .

(a) cleaning of forest   

(b) to grow plants

(c) to look after plants

(d) None of these

(3) The Red Data Book gives a list of none of these .

(a) endemic species

(b) extinct species

(c) natural species

(d) None of these

(4) Insitu conservation is onsite conservation

(a) off site conservation

(b) on site conservation     

(c) Both a and b

(d) None of these

(5) Wildlife Protection Act was implemented in 1972.

(a) 1986

(b) 1972   

(c ) 1973

(d) 1971

(II) Fill in the blanks

(1 ) WWF stands for World Wildlife Fund .

(2) The animal found in a particular area is known as endemic.

(3) Red Data Book is maintained by IUCN .

(4) Mudhumalai Wildlife Sanctuary is located in Nilgiris district .

(5) March 3 is observed as ‘ World Wildlife Day’ .

(III) Match the following

Gir National Park Madhya Pradesh
Sundarabans National park Uttara khand
Indira Gandhi National Park West Bengal
Corbett National Park Gujarat
Kanha National Park Tamil Nadu

Answer

Gir National Park Gujarat
Sundarabans National park West Bengal
Indira Gandhi National Park Tamil Nadu
Corbett National Park Uttara khand
Kanha National Park Madhya Pradesh

(IV) Answer very briefly .

(1 ) What is global warming?

There is a reflection of the solar energy that falls on the earth surface into the atmosphere. The greenhouse gases reflects a part of this energy back to the earth in order to retain its warmness and a portion travels towards the direction of space. But gases like methane and carbon dioxide plays an important role in trapping the heat energy within the atmosphere , which ultimately leads to an increase in temperature. This is known as global warming.

(2) What is known as extinct species?

Extinct species refers to those species, whose existence could no longer be traced on earth. Dinosaurs and Dodo are some of the most relevant examples. Deforestation, environmental changes and habitat degradation are some of the main reasons that are held responsible for the extinction of enormous dinosaurs.

(3) Give few examples for extinct species.

Dinosaurs and Dodo depicts a perfect example of extinct species.

(4) Name two endangered animals.

An endangered species refers to those species that are at the verge of extinction, which means they can become extinct at any point of time, as their presence on the earth has decreased to a considerable extent. Bengal tiger and snow leopard are some of the examples of endangered species.

(5) What is IUCN?

IUCN stands for International Union for Conservation of Nature. IUCN  plays an important role in maintaining the Red Data Book. It’s main purpose is to keep a record of the existence of every single species. Threatened, not threatened and unknown are mainly the three categories in which the Red Data Book classifies  the species .

(V) Answer briefly .

(1) What is biosphere reserve?

Biosphere acts as a protective area, with an aim of conserving the plants and animals. The large- scale human population also constitutes the part of it. This area mainly covers around 500 square kilometers. They play an important role in conserving natural ecosystem, species and genetic resources. The main purpose behind setting up these areas, was to prosper economic development.

(2) What is tissue culture?

Tissue culture refers to a procedure in which the plants cells, tissues, organs, seeds or other parts of plant grows in a clean environment on a nutrient medium.

(3) What is endangered species?  Give two examples.

An endangered species refers to those species that are at the verge of extinction, which means they can become extinct at any point of time, as their presence on the earth has decreased to a considerable extent. According to a report, there are nearly 132 species that are susceptible at the risk of encountering extinction. Bengal tiger and snow leopard are some of the examples of endangered species.

(4) Write the advantages of the Red Data Book .

The advantages of the Red Data Book are as follows :

  • It contributes in evaluating the population of a specific species.
  • The data provided in this book can be utilised for the purpose of evaluating the species at the global level.
  • This book can help in estimating the risk of extinction of species on a global basis.
  • A proper guidelines is provided by this book, so that measures can be implemented with an aim of safeguarding endangered species.

(5) Mention four main reasons for the conservation of forest.

Over the past 40 years, there has been a marked (60%) decrease in the size of population of animals, birds, reptiles, fish and amphibians and this information has been rendered by WWF (World Wildlife Fund) . So, it is a high time to conserve it now, so that something could be left for the subsequent generation. Conservation mainly signifies the protection and conservation of wildlife and natural resources. Conservation of biodiversity is extremely essential ,as it contributes in protecting,  maintaining and recovering endangered species. In- situ conservation and Ex- situ  conservation are mainly the two different types of conservation.

(6) What do you understand by the term bio magnification?

Due to the intoxicating environment , there has been a tremendous increase in contaminated substances and this increase in toxic substances are known by the term of bio magnification. Heavy metals like mercury , arsenic and pesticides are some of the examples of such contaminants . These substances then enters into the body of the organisms,through the food they eat . Then there is an accumulation of these toxins in the higher organisms , when they feed on the lower organisms that contains these toxic substances.

7) What is PBR?

People Bio – diversity Register refers to a document that is primarily designed for recording information of the locally available bio – resources that incorporates landscape and demography of a localized area. Bio – resources literally means all the biological organisms that are designated from the natural ecosystems like plants , animals and microorganisms . According to the provisions of Biological Diversity Act 2002 , a Bio – diversity Management Committee has been established in each localized institutions. Both National Biodiversity Authority and the State Biodiversity renders assistance to this committee in preparing the People’s Biodiversity Registers. The main purpose of preparing this register is to facilitate conservation of specific type of animals and natural environment. It also helps to gather information pertaining to biological diversity. The register contains a detailed account of biodiversity in fields relating to species , array of plants , sources of food , therapeutic sources and ancient forms of knowledge etc.

(VI) Answer in detail. 

(1) What is deforestation? Explain the causes and effects of  deforestation.

Forests are considered as an essential renewable resources . They not only performs an essential role in producing oxygen but they also contributes in maintaining the level of carbon dioxide in the atmosphere . We acquire many essential goods from forests like timber, paper and medical plants . But , people are destroying the forests all over the world with an aim of fulfilling their requirements. Both natural and human activities are held responsible for causing deforestation. Deforestation refers to the clearing of forest by man with an aim of using the land for different purposes. So ,due to this reason forests are destroyed by humans to a great extent.

The main causes of deforestation are as follows:

a ) Agricultural Expansion

The rise in population has led to a tremendous increase in the requirements of food production. So, due to this reason , ample quantities of trees are chopped down for the purpose of crop production and also for livestock grazing.

b) Urbanization

As cities are expanding to a considerable extent,due to this reason there are requirements of more lands for establishing residential housing and settlements. Urbanization is considered as a primary factor, that is held responsible for the causation of deforestation.

c) Mining

A large quantity of land is required for the purpose of mining coal, diamond and gold. For this reason, an ample quantity of trees are chopped down for clearing the forest area.

d) Construction of dams

The main reason behind constructing these huge dams was to provide water supply to the increasing number of populations, so as a result of which it was obligatory to clear the forest area.

e) Timber production

We require woods for fulfilling the requirements of our day to day life activities . There is a considerable demand of wood supply in those industries , that uses wood for manufacturing wooden products. As wood is used as a fuel, for this reason, great quantity of trees are chopped down for the purpose of supplying fuels.

f) forest fire

There is an usual expectation of forest fires from time to time. Both human and natural factors are held responsible for causing forest fires. In every year, nearly acres of forest land gets destroyed by the forest fires. This in turn poses a negative impact on both the economy as well as on the biodiversity.

g) Cyclones

Cyclones creates a massive scale destruction of the fauna onthe planet. They not only destroys the forest but also hampers the ecological balance of the surroundings.

Effects of deforestation

There is a remarkable contribution of forests in our life, without its presence, it will be extremely difficult for us to maintain our sustenance. But the forests are destroyed to a great extent due to the massive increase in population.

Some of the major effects of deforestation are as follows :

a ) Extinction of species

Extinct species refers to those species, whose existence could no longer be traced on earth. Dinosaurs and Dodo are some of the most relevant examples. Deforestation, environmental changes and habitat degradation are some of the main reason that are held responsible for the extinction of species.

b) Soil Erosion

Forest trees plays a significant role in protecting the soil from the scorching heat of the sun . But the soil gets exposed to the hot rays of the sun ,when these trees are chopped down. High environmental temperatures can affect the fertility of the soil, thus making it less productive in nature. So destruction of forests can ultimately lead to the problem of soil erosion.

c) Water cycle

Trees plays an important role in releasing water to the atmosphere by undergoing the process of transpiration. So, cutting down of trees can hamper the rate of water vapour that ultimately leads to a massive reduction in the amount of rainfall.

d) Floods

Trees performs an essential role in absorbing and storing huge quantity of water with the aid of their roots. So, there is a great disruption in the flow of water due to the massive destruction of trees which ultimately results in severe flooding.

e) Global warming

As we all know that, human beings intake oxygen and gives out carbon dioxide. During the process of photosynthesis, these carbon dioxide are absorbed by the trees and in turnreleases oxygen that is essential for our survival. Due to chopping down of trees, rate of carbon dioxide exceeds in the atmosphere.  Carbon dioxide, water vapour, methane , nitrous oxide and ozone constitutes the chief greenhouse gases in the atmosphere of the Earth. These gases are primarily responsible for the occurrence of global warming. There is a reflection of the solar energy that falls on the earth surface into the atmosphere. The greenhouse gases reflects a part of this energy back to the earth in order to retain its warmness and a portion travels towards the direction of space. But gases like methane and carbon dioxide plays an important role in trapping the heat energy within the atmosphere , which ultimately leads to an increase in temperature. This is known as global warming.

f) Destruction of home land

For indigenous people, forests acts as a major source of sustenance. So, cutting down of trees can bring about a negative impact on their subsistence.

(2) Discuss the advantages of in-situ and ex situ conservation.

When species are conserved in their natural habitats, then it is known as in situ -conservation.

The advantages of in- situ conservation are as follows:

  • This enhances the adaptive ability of the species to their natural habitat.
  • This creates an interactive environment, in which they can associate with one another.
  • There is a proper maintenance of natural habitat.
  • It is not very expensive and can be managed quite easily.
  • It helps in protecting the requirements of the indigenous people.

When species are conserved outside their natural habitat, then it is known as ex -situ conservation. There are establishment of zoos and botanical garden for preserving these species.

The advantages of ex -situ conservation are as follows:

  • It helps in averting the reduction of species.
  • These ways can be followed for breeding the endangered species.
  • It is useful for breeding endangered species, which can ultimately help in preserving those species that are at the higher risk of extinction.
  • It proves to be quite effective in executing scientific research.

(3) Write about the types of conservation.

Conservation

Conservation mainly signifies the protection and conservation of wildlife and natural resources. Conservation of biodiversity is extremely essential, as it contributes in protecting, maintaining and recovering endangered species. In- situ conservation and Ex- situ conservation are mainly the two different types of conservation.

In – situ conservation

When species are conserved within their natural ecosystem, then it is known as in -situ conservation. This can be acquired by protecting their natural habitat and also by maintaining these threatened species in some protective areas like national parks, wildlife sanctuaries and biosphere reserves. The main aim of designing these areas, was to conserve and protect the endangered species that are subjected to the higher risk of extinction.

a ) National parks

National park is an area that was primarily designed for the improvement of the wild animals . Forestry ,grazing or cultivation are for instance, some of the activities that was strictly prohibited in these areas. Even the exclusive rights of private ownership was also forbidden.

b) Wildlife sanctuaries

The main reason behind setting up this natural reserves was to render protection to the wild animals by adopting a proper conservation technique. Harvesting of timber and accumulation of forest products are for instance, some of the human activities that were permitted in these areas. Even the rights of private ownership was also granted.

c) Biosphere reserves

Biosphere acts as a protective area, with an aim of conserving the plants and animals. The large- scale human population also constitutes the part of it. This area mainly covers around 500 square kilometers. They play an important role in conserving natural ecosystem, species and genetic resources. The main purpose behind setting up these areas, was to prosper economic development.

Ex- situ conservation

When species are conserved outside their natural habitat, then it is known as ex -situ conservation. There are establishment of zoos and botanical garden for preserving these species.

a ) Botanical gardens

It is a place which facilities the growth of varieties of fruits, species, trees and vegetables. These places renders a pleasant and soothing environment.

b) Zoological parks

The regions where wild and endangered species are conserved is called zoological parks. There are about 800 zoological parks in India.

c) Tissue culture

Tissue culture refers to a procedure in which the plants cells, tissues, organs, seeds or other parts of plant grows in a clean environment on a nutrient medium.

d) Seed bank

The seed banks acts as a storage unit in which the dried seeds are stored at a very minimal temperature. The millennium seed bank in England is considered as one of the largest seed bank in the world.

e) Cryo Bank

It is a technique that is mainly used for the purpose of preserving a seed or  embryo at a very minimal temperature. This method also proves to be very effective for conserving endangered species.

(4) Write a note on Blue Cross .

Blue Cross was founded in the year 1897 and it was a registered animal welfare charity in the United Kingdom. The main aim of this charity is to provide a proper shelter for every pet, so that they can also reap the benefits of a hearty and healthy life. It renders assistance to those pet owners, who fails to provide private veterinary treatment to their pets. It also provides protective shelters to the abandoned animals. It tries to inculcate a sense of responsibility among the people ,in areas related to animal ownership. The Blue Cross of India was founded by Captain V. Sundaram in the year 1959. He was not only an Indian pilot but he also established his career as an animal welfare activist. There are several animal welfare events that operates under the guidance of this charity and this charity is regarded as one of the largest animal welfare organization in present times. Due to its significant contribution in the fieldof welfare related activities, Blue Cross of India was awarded with several national and international awards. Here, the volunteers takes the administrative responsibility for running this organization. Its central office is situated at Guindy, Chennai , with all the essential facilities and services like healthcare centers, shelters, ambulance facilities and birth control programme of animals. Providing shelters, adoption, re- housing, birth control scheme of animals, rendering ambulance facilities and proper maintenance of hospitals are for instance, some of the major activities of the organization.

(VII ) Higher Order Thinking Questions.

(1) Is it possible to find dinosaurs today ? Why?

The species which possessed the ability to adapt to environmental changes are likely to survive but the ones that are unable to do so become extinct in the process of evolution. Some sudden natural disaster or environmental changes are considered to be one of the primary reasons for the extinction of enormous dinosaurs. For this reason, it is not possible to find dinosaurs in present times.

(2) Animals are affected by deforestation. How?

Both natural and human activities are held responsible for causing deforestation. Deforestation refers to the clearing of forest by man with an aim of using the land for different purposes. So ,due to this reason forests are destroyed by humans to a great extent. The destruction of the forests leads to the displacement of wild animals . So, this forces them to leave their own place and move out for the purpose of finding shelter. This displacement of animals brings about a major affect on the food chains, which ultimately leads to the scarcity of food. Some animals may also become prey of hunters or may die due to accident and in this way, they get separated from their groups. So, these  are the several ways in which, deforestation poses a negative impact on the life of animals.

(3) Why did the numbers of tiger and black buck decrease?

Deforestation, extensive hunting and habitat destruction are considered to be some of the primary reasons for a rapid decline in the number of tigers and black buck. Due to destruction of forests, there is a gradual decline in the number of herbivorous animals, so as a result of which, tigers are experiencing several problems in finding their food. Therefore, these are the several factors that are held responsible for a gradual reduction in the number of tiger and black buck.

Updated: December 11, 2021 — 6:46 pm

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