Samacheer Kalvi Class 8 Science Unit 22 Crop Conservation of Plants and Animals Solutions
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Unit 22 Crop Conservation of Plants and Animals Exercise Questions Solutions :
(I) Choose the best answer :
(1) The plants found in a particular area are known as ___
Correct Option → (b)
The plants found in a particular area are known as flora.
(2) Deforestation means
(a) Cleaning of forest
(b) To grow plants
(c) To look after plants
(d) None of these
Correct Option → (a)
Deforestation means Cleaning of forest.
(3) The red data book gives a list of
(a) Endemic species
(b) Extinct species
(c) Natural species
(d) None of these
Correct Option → (d)
None of these options are not associated with Red data book.
(4) Insitu conservation is ____
(a) Off site conservation
(b) On site conservation
(c) Both a and b
(d) None of these
Correct Option → (b)
Insitu conservation is on site conservation.
(5) Wildlife protection act was implemented in
Correct Option → (b)
Wildlife protection act was implemented in 1972.
(II) Fill in the blanks
(1) WWF stands for ___
(2) The animal found in a particular area is known as ___
(3) Red Data Book is maintained by ___
(4) Mudhumalai Wildlife Sanctuary is located in ___ district.
(5) ___ is observed as ‘World Wildlife Day’
(1) → World Wild Life Fund
(2) → Fauna
(3) → IUCN
(4) → Theni district
(5) → 3 March
(IV) Answer very briefly
(1) What is global warming?
The gases like carbon dioxide and methane mix in the atmosphere trap heat energy inside the atmosphere leads to increasing in temperature is known as Global warming.
(2) What is known as extint species?
The species which is no longer exist on earth are called extinct species.
(3) Give few example for extinct species.
Few examples of extinct species are Dinosaurs, Dodo.
(4) Name two endangered animals.
Snow leopard, Bengal tiger, Asiatic lion , Indian giant squirrel etc are endangered species.
(5) What is IUCN?
IUCN stands for international union for conservation of nature.
(V) Answer briefly
(1) What is biosphere reserve?
Biosphere reserve is the protected area where human population also forms the part of the system. The area of these species will be around 5000 sq. Km. The biosphere conserve the Eco system species and genetic resources. They are mainly setup for economic development. For example → Nanda Devi-U.P.
(2) What is tissue culture?
It is the technique of growing plant cells, tissues, organs, seeds or other plant parts in a sterile environment on a nutrient medium is known as tissue culture.
(3) What is endangered species? Give two examples.
Endangered species are those species which are highly risk of extinction. It means there are only few of them left on the earth and soon they might extinct. For example- snow leopard, Bengal tiger, Indian giant squirrel etc.
(4) Write the advantages of the Red Data Book.
Advantages of Red Data Book :
(a) It helps to evaluate the population of a particular species.
(b) The data given in this book can be used to evaluate the species at the global level.
(c) The risk of a species becoming globally extinct can be estimated with the help of this book.
(d) It provides guidelines for implementing measures for protecting endangered species.
(5) Mention four main reasons for the conservation of forests.
Reasons for the conservation of forest :
(a) Conservation of forest improves the quality of air we breathe by reducing carbon dioxide in it.
(b) Conservation of helps the wild animals and even humans to have shelter and to find their food source.
(c) Conservation of forest saves the lands for wild animals.
(d) Trees planted can increase the water vapor in the atmosphere to get the rainfall.
(6) What do you understand by the term bio magnification?
Bio-magnification is the increases in contaminated substances due to the intoxicating/harmful to environment. The contaminants are like DDT, Arsenic and pesticides. Which are taken by the organism and they are toxic to them. And it also affects on the reproduction and development of marine/ aquatic organism. The chemicals and toxins are released into water bodies are disrupt the food chain. It means bio magnifications are the substance which harmful for some organism when they are released or mixed in environment.
(7) What is PBR?
PBR are stands for the peoples biodiversity register. It is a document which contains information on locally available bio- resources including landscape and demography of a particular area or village.
The committee prepares for peoples biodiversity registers with the guidance and technical support of national biodiversity authority and the state biodiversity boards.
(VI) Answer in detail
(1) What is deforestation? Explain the causes and effects of deforestation.
Destruction of forest in order to make the land available for different uses is known as deforestation.
Causes of deforestation :
(a) Cyclones : cyclones are destroyed the trees on a massive scale they not only destroyed trees but also affects the live hood of so many peoples.
(b) Forest fire : sometimes it caused by humans, accidents or natural factors. Forest fire has tremendous effects on biodiversity and the economy as well.
(c) Urbanization : forests are destroyed to obtaining land for construction, of roads, house, buildings etc.
Effects of deforestation :
(a) Extinction of species : deforestation results in the loss of many wonderful species of plants and animals.
(b) Floods : 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 area.
(c) Increasing the level of pollution also effect of the deforestation.
(2) Discuss the advantages of in-situ and ex-situ conservation.
Advantages of in-situ conservation :
(a) Species can be adapted to their habitat.
(b) Species can interact with each other.
(c) Natural habitat is maintained
(d) It is less expensive and easy to mange
(e) Needs of indigenous people are protected.
Advantages of ex-situ conversations :
(a) It prevents the decline of species.
(b) Endangered animals can be breaded in these ways.
(c) Threatened species are breaded and released in natural environment.
(d) It is useful for conducting research and scientific work.
(3) Write about the types of conservation.
There are two types of conversations are seen in-situ and ex-situ conversations.
(a) In-situ conservation : In this type of conservation, conservation of living organism within the natural ecosystem in which they occur. In this protection of natural habitat and maintenance of endangered species in certain protected areas such as national parks, wildlife or bird sanctuaries and biosphere reserves in India there are about 73 national parks, 416 sanctuaries and 12 biosphere reserves.
(b) Ex-situ conversations : In this conservation of wildlife outside their habitat. Like establishing zoos and botanical gardens conservation of genes sealing and tissue culture are some of the methods for conservation of this species.
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