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8th Science Guide Lesson 22 Conservation of Plants and Animals

8th Science Guide Lesson 22 Conservation of Plants and Animals

8th Std Science Guide Lesson  Conservation of Plants and Animals | English Medium

8th Science Guide Unit 22 Conservation of Plants and Animals book back answers. 8th Standard Science Guide English Medium Book Back Answers. 8th Science Samacheer kalvi guide Tamil Medium and English Medium Book Back and additional questions and answers. 8th Text Book download pdf. 8th std All Subject Guide

8th Science Guide Lesson 22 Conservation of Plants and Animals

I. Choose the best answer.

1. The plants found in a particular area are known as ________

  1. fauna
  2. flora
  3. endemic
  4. rare

Ans : endemic

2. Deforestation means ______

  1. cleaning of forest
  2. to grow plants
  3. to look after plants
  4. None of these.

Ans : None of these.

3. The Red Data Book gives a list of _________

  1. extinct species
  2. natural species
  3. None of these

Ans : None of these.

4. Insitu conservation is________

  1. of site conservation
  2. on site conservation
  3. Both a and b
  4. None of these

Ans : on site conservation

5. Wildlife Protection Act was implemented in ________

  1. 1986
  2. 1972
  3. 1973
  4. 1971

Ans : 1972

II. Fill in the blanks.

  1. WWF stands for _________Ans : World Wildlife Fund.
  2. The animal found in a particular area is known as ___________.Ans : endemic
  3. Red Data Book is maintained by ___________.Ans : IUCN
  4. Mudhumalai Wildlife Sanctuary is located in ___________ districtAns : Nilgiris
  5. __________ is observed as ‘World Wildlife Day’Ans : March 3

III. Match the following.

  1. Gir National Park – Madhya Pradesh
  2. Sundarabans National Park – Uttarangal
  3. Indira Gandhi National Park – West Bengal
  4. Corbett National Park – Gujarat
  5. Kanha National Park – Tamil Nadu

Ans : 1 – d, 2 – c, 3 – e, 4 – b, 5 – a

IV. Answer in brief:

1. What is global warming?

  • Gases such as methane and carbon dioxide accumulating in the atmosphere trap the heat energy inside the atmosphere leading to increase in temperature. This is called global warming.

2. What is known as extint species?

  • Species which no longer exist on earth are called extinct species.

3. Give few example for extinct species.

  • Dinosaurs
  • Dodo

4. Name two endangered animals.

  • Snow Leopard
  • Bengal Tiger

5. What is IUCN?

  • International Union for Conservation of Nature – IUCN

VIII. Answer in detail:

1. What is biosphere reserve?

  • Biosphere is a protected area where human population also forms the part of the system. The area of these places will be around 5000 square kilo meters. Tey conserve the eco system, species and genetic resources. These areas are set up mainly for economic development.

2. What is tissue culture?

  • It is a technique of growing plant cells, tissues, organs, seeds or other plant parts in a sterile environment on a nutrient medium.

3. What is endangered species? Give two examples.

  • An endangered species is an animal or a plant that is considered to be at the risk of extinction.
  • It means that there are only few of them left on the earth and soon they might
  • It is reported that nearly 132 species of plants and animals are critically endangered in India.
  • Snow leopard, Bengal tiger, Asiatic lion, Purple frog and Indian giant squirrel are some of the endangered animals in India

4. Write the advantages of the Red Data Book.

  • It helps to evaluate the population of a particular species.
  • The data given in this book can be used to evaluate the species at the global level.
  • The risk of a species becoming globally extinct can be estimated with the help of this book.
  • It provides guidelines for implementing protective measures for endangered species.

5. Mention four main reasons for the conservation of forests.

  • According to WWF (World Wildlife Fund) there has been 60% decrease in the size of population of animals, birds, fish, reptiles and amphibians over the past 40 years.
  • In order to leave something for the future generation, we need to conserve it now.
  • Conservation is the protection, preservation, management of wildlife and natural resource such as forest and water.
  • Conservation of biodiversity helps us to protect, maintain and recover endangered animals and plant species. Conservation is of two types.

They are:

  1. In-situ conservation (within habitat)
  2. Ex-situ conservation (outside the habitat)

6. What do you understand by the term bio magnification?

  • Biomagnifcation is the increase in contaminated substances due to the intoxicating environment.
  • The contaminants might be heavy metals such as mercury, arsenic, and pesticides such as polychlorinated biphenyls and DDT (Dichloro Diphenyl Trichloro ethane). These substances are taken up by the organisms through the food they consume.
  • When the organisms in the higher food chain feed on the organisms in the lower food chain containing these toxins, these toxins get accumulated in the higher organisms.

7. What is PBR?

  • People’s Biodiversity Register is a document which contains comprehensive information on locally available bio-resources including landscape and demography of a particular area or village.
  • Bio-resources mean plants, animals and microorganisms or parts there of, their genetic material and by-products with actual or potential use or value.
  • A Biodiversity Management Committee is set up in each local body according to the provisions of Biological Diversity Act, 2002.
  • This committee prepares the People’s Biodiversity Registers with the guidance and technical support of National Biodiversity Authority and the State Biodiversity Boards.
  • Preparation of this register promotes conservation, preservation of habitats and breed of animals and gathering of knowledge relating to biological diversity.
  • The register entails a complete documentation of biodiversity in the area related to the plant, food source, wildlife, medicinal source, traditional knowledge etc.

VI. Answer in detail

1. What is Deforestation? Explain the causes and effects of Deforestation.

Causes of Deforestation

Agricultural Expansion

With increasing population, there is an overgrowing demand for food production.

Hence, large amount of trees are chopped down for crops and for cattle grazing.


With the expansion of cities more land is needed to establish housing and settlement.

Forests are destroyed to meet all these needs.


Mining of coal, diamond and gold require a large amount of forest land. So, a large number of trees is cut down to clear the forest area.

Construction of dams

To provide water supply to the increasing population, large size dams are constructed.

Hence, a great extend of forest area is being cleared.

Forest fire

In many forests, fires are usually expected from time to time. They may be caused by humans, accidents or natural factors.


Cyclones destroy the trees on a massive scale. They not only destroy the trees but also affect the livelihood of so many people who depend on them.

Effects of Deforestation

  • Our survival without forest will be very difficult.
  • They supply us the oxygen we need, cause rainfall and provide so many things needed for our life.
  • In India alone 10 lakh hectares of forests are destroyed which has resulted in so many harmful effects.

Extinction of species

Deforestation has resulted in the loss of many wonderful species of plants and animals and many are on the verge of extinction.

Soil Erosion

Widespread trees in the forests protect the soil from the heat of the sun. When the trees are cut down, soils are exposed to the sun’s heat. When the trees are cut down, soil is eroded and washed away along with the nutrients.

Water cycle

Trees suck the water from the roots and release the water into the atmosphere in the form of vapour during transpiration. When trees are cut down the amount of water vapour released decreases and hence there is a decrease in the rainfall.


Trees absorb and store a large amount of water with the help of their roots. When the trees are cut down, the flow of water is disrupted and it leads to flooding in some areas.

2. Discuss the advantages of Insitu and exsitu conservation.

Advantages of In-situ conservation

  • Species can be adapted to their habitat.
  • Species can interact with each other.
  • Natural habitat is maintained.
  • It is less expensive and easy to manage.
  • Interests of indigenous people are protected

Advantages of Ex-situ conservation

  • It prevents the decline of species.
  • Endangered animals can be breeded in these ways.
  • Treatened species are breeded and released in natural environment.
  • It is useful for conducting research and scientifc work.

3. Write about the types of conservation.

Conservation is of two types. They are:

  • In-situ conservation (within habitat)
  • Ex-situ conservation (outside the habitat)

In-situ conservation

  • It is nothing but conservation of living resources within the natural ecosystem in which they occur.
  • This is achieved by protection of natural habitat and maintenance of endangered species in certain protected areas such as national parks, wildlife or bird sanctuaries and biosphere reserves.

National Parks

  • A National park is an area which is strictly reserved for the betterment of the wildlife.
  • Here, activities like forestry, grazing or cultivation are not permitted.

Wildlife sanctuaries

  • A sanctuary is a protected area which is reserved for the conservation of animals only.
  • Human activities like harvesting of timber, collection of forest products and private ownership rights are allowed here.
  • Controlled interference like tourist activity is also allowed.

Biosphere reserves

  • Biosphere is a protected area where human population also forms the part of the system.
  • The area of these places will be around 5000 square kilometers.
  • They conserve the ecosystem, species and genetic resources.

Ex-situ Conservation

  • It is the conservation of wildlife outside their habitat.
  • Establishing zoos and botanical gardens, conservation of genes, seedling and tissue culture are some of the strategies followed in this method.

Botanical gardens

  • It is a place where flowers, fruits and vegetables are grown.
  • These places provide a healthy and calm environment.

Zological parks

  • Zological parks are the areas where wild animals are conserved.
  • In India there are about 800 zological parks.

Tissue Culture

  • It is a technique of growing plant cells, tissues, organs, seeds or other plant parts in a sterile environment on a nutrient medium.

Seed bank

  • The seed bank preserves dried seeds by storing them in a very low temperature.
  • The largest seed bank in the world is the Millennium Seed Bank in England.

Cryo Bank

  • It is a technique by which a seed or embryo is preserved at a very low temperature.
  • It is usually preserved in liquid nitrogen at –1960C.
  • This is helpful for the conservation of species facing extinction.

4. Write a note on Blue Cross.

  • Blue Cross is a registered animal welfare charity in the United Kingdom, founded in 1897 as ‘Our Dumb Friends League’.
  • The vision of this charity is that every pet will enjoy a healthy life in a happy home. The charity provides support for pet owners who cannot afford private veterinary treatment, helps to find homes for unwanted animals, and educates the public in the responsibilities of animal ownership.
  • Captain V. Sundaram founded the Blue Cross of India, the largest animal welfare organization of Asia in Chennai in the year 1959.
  • He was an Indian pilot and animal welfare activist.
  • Now, Blue Cross of India is country’s largest animal welfare organizations and it runs several animal welfare events like pet adaptation and animal right awareness.
  • Blue Cross of India has received several international and national awards. This organization is entirely looked after by volunteers.
  • The main office is located at Guindy, Chennai, with all amenities like hospitals, shelters, ambulance services and animal birth controls, etc.
  • Activities of the organization include, providing shelters, re-homing, adoption, animal birth control, maintaining hospitals and mobile dispensary and providing ambulance services.

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