Class 12 Biology Chapter 15 Biodiversity and Conservation

Class 12 Biology Chapter 15 Biodiversity and Conservation The answer to each chapter is provided in the list so that you can easily browse through different chapters Assam Board HS 2nd Year Biology Chapter 15 Biodiversity and Conservation Question Answer.

Class 12 Biology Chapter 15 Biodiversity and Conservation

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Also, you can read the SCERT book online in these sections Solutions by Expert Teachers as per SCERT (CBSE) Book guidelines. These solutions are part of SCERT All Subject Solutions. Here we have given Assam Board Class 12 Biology Chapter 15 Biodiversity and Conservation Solutions for All Subjects, You can practice these here.

Biodiversity and Conservation

Chapter – 15


Very Short Answer Type Questions

Q.1. According to IUCN (2004) there are slightly more than ____ million plant and animal species described from earth. 

Ans : 1.5 

Q.2. Species diversity _____ as one moves away from the equator to the pole. 

Ans : Decreases.

Q.3. The rain forest covers no more than ____ percent of earth surface. 

Ans : 6 

Q.4. Exploring molecular genetic and species -level diversity for products of economic importance is called_____

Ans : Bioprospecting.

Q.5. There are _____ number of biosphere reserves in India. 

Ans : 15. 

(B). True Or False (1 mark each) : 

Q.1. Plots with higher number of species show less year to year variation in total biomass. 

Ans : True.

Q.2. Water hyacinth (Eicchornia) is a native species of India. 

Ans : False.

Q.3. The higher productivity of tropics is due to higher availability of solar energy. 

Ans : True.

Q.4. There are two biosphere reserves in Assam. 

Ans : True.

Q.5. Forest cover in Assam is about 50% of the total geographical area. 

Ans : False.

Q.6. Kaziranga is the abode of pigmy hog. 

Ans : False.

Q.7. The total land area of Orang National park is_____km²

Ans : 72 

(C). Very Short Answer Questions: (1 Mark Each) : 

Q.1. What is endemism in terms species distribution? 

Ans : It refers that species is confined to that region and not found anywhere else. 

Q.2. Give two examples of invasive weed species that threatens our native species. 

Ans : Parthenium and water hyacinth. 

Q.3. Since the origin of life on earth how many episodes of mass extinction occurred? 

Ans : Five.

Q.4. Write the equation of Species Area relationships in a logarithmic scale. 

Ans : log S = log C+2 log A 

         Where, S = Species richness 

                      A = Area 

                      Z = Slope of the line (regression co-efficient) 

                      C = y- intercept

Q.5. Name the important components of Biodiversity. 

Ans : The important components of Biodiversity are-Genetic Diversity, Species Diversity and Ecological Diversity. 

Q.6. Write the name of the Biodiversity Hotspots that cover exceptionally high biodiversity regions of North east India. 

Ans : Indo Myanmar Hotspot. 

Q.7. What do you understand by “Sacred Grooves”? 

Ans : India has a history of religious and cultural traditions that emphasised protection of nature. In many cultures, tracts of forests were set aside and all the trees and wildlife within were venerated and given total protection which are known as sacred grooves. 

Q.8. Amongst the animals which is the most species rich taxonomic group? 

Ans : Insects.

Q.9. What is ex-situ conservation? 

Ans : In ex-situ conservation, threatened animals and plants are taken out from their natural habitat and placed in special setting where they can be protected and given special care, eg. Zoological Park. 

Q.10. What is it called where animals and plants are conserved in their own habitat? 

Ans : In situ conservation. 

Q.11. Write anyone importance of bio-diversity. 

Ans : Biodiversity plays a major role in many ecosystem services that nature provides. 

Q.12. What is species diversity? 

Ans : The diversity of organisms at species level is known as species diversity. 

Q.13. Give the biological name of the African catfish, which is introduced in the Indian water bodies for aquaculture purposes and is threatening the existence of the indigenous cat fishes. 

Ans : Clarius gariepinus.

(D). Short Answer Questions (2 Marks Each) : 

Q.1. Write briefly on the three levels of biological diversity. 

Ans : Biodiversity is the term which describes the combined diversity at all the levels of biological organisation. 

There are three levels of biodiversity : 

(i) Genetic Diversity : A single species might show high diversity at the genetic level over its distribution range. For example India has more than 50,000 genetically different strains of rice and 1,000 varieties of mango. 

(ii) Species Diversity : It is the diversity at the species level. For example, the Western Ghats have a greater amphibian species diversity than the Eastern Ghats. 

(iii) Ecological Diversity : At the ecosystem level, India for instance, with its deserts, rain forests, mangrooves, coral rufs. Wet lands, estuaries and alpine nuadowshas a greater ecosystem diversity than Scandinavian country like Norway. 

Q.2. State the importance of species diversity to the ecosystem. 

Ans : The importance of species diversity to the ecosystem is still a matter of research. Different scientists have carried out different experiment for this. David Tilman’s long turn ecosystem experiment showed that increased diversity contributed to higher productivity. Though it is not understand completely how species richness contributes to well being of an ecosystem but it is clear from the studies that rich biodiversity for the survival of the human race on this planet. 

Q.3. Why it is dangerous to introduce alien species in an area? 

Ans : When alien species i.e, species from the outside of the country are introduced unintentionally or deliberately for whatever purpose, some of them turn invasive and cause decline or extinction of indigenous species. For example, the introduction of the African catfish Clarius gariepinus for aquaculture purposes is posing a threat to the indigenous catfish in our rivers.

Q.4. How habitat fragmentation causes depletion of biodiversity? 

Ans : When large habitats are broken up into small fragments due to various human activities, mammals and birds requiring large territories and certain animals with migratory habits are badly affected, leading to population declines this is the most important cause driving animals and plants to extinction. The most dramatic examples of habitatless come from tropical rain forests. 

Q.5. Define coextinction. 

Ans : When a species become extinct, the plant and animal species associated with it is an obligatory way also become extinct. This is known as co-extinction. For example, when a host fish species become extinct, its unique assemblage of parasites also meets the same fate. 

Q.6. State the role of Zoos and botanical gardens in ex situ conservation. 

Ans : When an animal or plant unable to continue their race in natural wild habitat, then all these threatened animals or plants are taken out from their natural habitat and placed in special setting where they can be protected and given special care. These process is known as ex-situ conservation. Zoological parks and botanical garden serve this purpose. There are many animals and plants that now become extinct in the wild but continue to be maintained in zoological parks and botanical gardens. 

Q.7. Give the definition of protected areas. 

Ans : Protected area is a specialised area in large forest where special protection is provided to rare and endangered wild species. No person is allowed to enter this area except the persons of the forest department.

Q.8. What is national park? How many national parks are there in Assam? 

Ans : The National Park can be defined as “an area dedicated by legislation for all time to come to conserve the natural and historical objects therein, in such a manner and by such means. Which leave them uninpared, for enjoyment of future generations, with such modification as local conditions may demand. 

There are 5 national parks in Assam. 

Q.9. Give the faunal elements of Pabitora wildlife sanctuary. 

Ans : The faunal element of Pobitora wild life sanctuary are-One horned rhino, Monkey, Deer, Wild buffalo, Different specis of snake,lizard, prids, inseets, snails, fishes in aguatic areas etc. 

(E). Short Answer Questions (3 Marks Each) : 

Q.1. “India is one of the 12 mega diversity countries of the world”- explain the statement. 

Ans : Although India has only 2.4 percent of the world land area, its share of the global species diversity is an impressive 8.1 percent. That is what makes our country one of the 12 mega diversity countries of the world. 

Nearly 45,000 species of plants and twice as many of animals have been recorded from India. 

Three biodiversity hotspot regions, among the 34 hotpots of the world, are from India. 

These are : 

(i) Indo Berma.

(ii) Himalaya. and 

(iii) Western Ghats and Sri Lanka. These cover our countries exceptionally high biodiversity regions. Moreover these regions have a very high levels of species richness and high degree of endemism. 

Q.2. Write briefly on the diversity of tropical Amazonian rain forest of South America. 

Ans : The diversity of Amazon rain forest is rich. It contains about 40,000 species of different plants, 3,000 of fishes, 1,300 of birds, 427 of mammals, 427 of amphibians, 378 reptiles and more than 1,25,000 invertebrates and many more yet to be discovered. 

Q.3. Explain the “Rivet Popper Hypothesis” in the context of extinction of species. 

Ans : Rivet popper hypothesis was put forwarded by Standford Ecologist Paul Ehrlich. This refers that the species diversity is responsible for the proper functioning of an ecosystem. He described the hypothesis by taking the example of an aeroplane. As in an airplane all parts are joined together

using thousands of rivets, an ecosystem is also formed by many different species. If every passenger travelling in its starts popping a rivet to take home, initially it may not affect flight safety but as more and more rivets are removed, the plane become dangerously weak over a period of time. 

Loss of rivets on the wings is much more serious threat to flight safety than loss of a few rivets on the seats or windows inside the plane. Similarly due to human activities if species are destroyed or killed directly or indirectly then within a period of time some species may extinct from the ecosystem. This may affect the proper functioning of the ecosystem but if the extinct species is a key species that drive major ecosystem function their the whole ecosystem may be destroyed also. 

Q.4. What are the consequences of loss of biodiversity? 

Ans : The biodiversity wealth of the planet has be declining due to human civilization and human activity. These are due to destruction of forests for fulfilling different types of human needs by themselves. For example – the colonisation of tropical pacific Islands by humans is said to have led to the extinction of more than 2,000 species of native birds. The IUCN Red List (2004) documents the extinctions of 784 species among which 338 are vertebrates, 359 invertebrates and 87 plants in the last 500 years. Some recent extinctions include – dodo (Mauritius), quagga (Africa), thylacine (Australia) etc. The last twenty years alone have witnessed the disappearence of 27 species. Careful analysis of records shows that extinctions across taxa are not random, presently 12 percent of all bird species, 23 percent of all mammal species. 32 percent of all amphibian species and 31 percent of all gymnosperm species in the world face the threat of extinction. 

From a study of the history of life on Earth before humans appeared on scene, the causes of species extinctions were natural. But the current species extinction rates are estimated to be 100 to 1,000 times faster than in the pre-human times and according to scientists if the present trends continue, nearly half of all the species on earth might be wiped out within the next 100 years. 

In general, loss of biodiversity in a region may lead to : 

(a) decline in plant production.

(b) lowered resistance to environmental perturbations such as draught. 

(c) increased variability in certain ecosystem processes such as productivity, water use and pest and disease cycles. 

(d) Affected the animals life by loss of habitat etc. 

Q.5. Give the ethical arguments for conserving biodiversity.

Ans : The ethical argument for conserving biodiversity relates to what we are to millions of plants, animals and microbe species with whom we share this planet, philosophically or spiritually, we need to realise that every species has an intrinsic value, even if it may not be of current or any economic value to us. We have a moral duty to care for their well- being and pass on our biological legacy in good order to future generations. Conserving biodiversity is a mode of insurance for the next generation and for the better future of the planet. 

Q.6. Give a brief account of International convention and Summit held for cause of conservation of biodiversity and sustainable development. 

Ans : The historic conventions on biological diversity (The Earth Summit) held in Rio de Janerio in 1992, called upon all nations to take appropriate measures for conservation of biodiversity and sustainable utilisation of its benefits. In a follow up, the world Summit on sustainable development held in 2002 in Johannesburg, South Africa, 190 countries pledged their commitment to active by 2010, a significant reduction in the current rate of biodiversity loss at global, regional and local levels. 

Q.7. Write a note on biosphere reserve with special reference to Assam. 

Ans : Biosphere reserves are the protected forest areas which lies under Man and Biosphere Programme (1986). 

The main objectives of these kinds of reserves are : 

(i) Conservation of representative samples of ecosystems. 

(ii) Providing long term in situ conservation of genetic diversity of plants animals. 

(iii) Providing facilities research, monitoring, education training. 

(iv) Promotion of sustainable management of living resources. 

(v) Dissemination of experience for promotion of sustainable management of natural areas. 

In India there are 14 Biosphere Reserves. Out of all, two areas in our state – Assam and They are- 

(a) Kaziranga National Park or Kaziranga Biosphere Reserve. 

(b) Manas National Park or Manas Biosphere Reserve.

Q.8. Make a list of six endangered animal species of Manas National Park. 

Ans : The endangered animals from Manas are : 

(a) Golden langur – Presbytes geei. 

(b) Pigy Hog. 

(c) Golden Cat. 

(d) Hispid Hare. 

(e) One Horned Rhino-Rhinoceros unicornis.

(f) Wild Dog. 

Q.9. List the different elephant reserves of Assam. 

Ans : (i) Kaziranga national park.

(ii) Karbi Anglong Elephent Reserve.

(iii) Sonitpur Elephant Reserve. and

(iv) Nambor Forest.

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