Class 12 Biology Chapter 13 Biodiversity and Its Conservation Solutions. Explore Class 12 Biology Chapter 13 Biodiversity and Its Conservation Solutions with clear answers, important questions, and exam-focused explanations to understand biodiversity, learn conservation methods, and prepare confidently for exams.

Class 12 Biology Chapter 13 Biodiversity and Its Conservation Solutions

A. Very Short Answer Questions (1 mark each)

1. Name two endangered animal species found in India.

Ans: Rhinoceros and hippopotamus.

2. What is genetic diversity? HS ’24

Ans: Genetic diversity refers to the variation in the genetic composition of organisms. It includes variations in the genome, such as chromosomes, genes, and nucleotides.

3. What is the Red Data List?

Ans: The list of endangered or threatened species is called the Red Data List. It contains information about the characteristics of species, their conservation status, and their distribution.

4. What is the relationship between endemism and species distribution?

Ans: Endemic species are restricted to a particular geographical area rather than being widely distributed. Their distribution is limited, and they are found only in specific regions.

5. What are the important components of biodiversity?

Ans: Genes, species, and ecosystems.

6. What are sacred groves?

Ans: Since ancient times, certain forests or parts of forests in India have been protected as sacred places for religious or cultural reasons. Such areas are called sacred groves.

7. Which class of animals is exceptionally rich in species?

Ans: Insects.

8. How many mass extinction events have occurred since the origin of life on Earth?

Ans: Five.

9. What does species diversity mean?

Ans: Species diversity refers to the variety of species present in a particular area.

10. What is ex situ conservation?

Ans: When an organism cannot be conserved in its natural habitat or under its natural environmental conditions, it may be conserved elsewhere, such as in botanical gardens, zoological parks, or wildlife parks. This is called ex situ conservation.

11. Mention one important aspect of biodiversity.

Ans: The structure, stability, and services of an ecosystem depend on biodiversity.

12. What is conservation called when animals are protected in their natural habitats?

Ans: In situ conservation.

Fill in the blanks

13. India has __________ biosphere reserves.

Ans: 14.

14. The exploration of genetic and species-level diversity for economic products is called __________.

Ans: Bioprospecting.

15. Species diversity __________ as one moves from the equatorial region towards the poles.

Ans: Decreases.

16. Assam has __________ biosphere reserves.

Ans: Two.

17. A __________ park is established primarily for the conservation of animals.

Ans: National.

18. Biodiversity increases from the __________ region towards the equator.

Ans: Temperate.

19. Of every 10 animal species on this planet, 7 are __________.

Ans: Insects.

20. What is ecosystem diversity?

Ans: Ecosystem diversity refers to the variety of ecosystems present at different levels of organisation in a region.

21. Who coined the term “biodiversity”?

Ans: W. G. Rosen.

22. What is species diversity?

Ans: Species diversity refers to the variety of different species found together in a particular region.

23. Name two regions of India rich in biodiversity.

Ans: North-East India and the Western Ghats.

24. What percentage of the world’s flora is found in India?

Ans: 30%.

B. Short-Answer Questions (Biodiversity and Its Conservation Solutions)

25. Why can the introduction of exotic species into a region be dangerous?

Ans: Introducing an exotic species into a new country or region may create several problems. The introduced species may have no natural competitors, pathogens, insect predators, or other organisms that control its population in its original habitat. As a result, it may multiply rapidly and adversely affect native species.

26. Define co-extinction.

Ans: Co-extinction occurs when the extinction of one species leads to the extinction of another species that depends on it for survival.

27. Define a protected area.

Ans: A protected area is a clearly defined geographical region in which specific rules and regulations are established to conserve species diversity. These rules help prevent damage to plants and animals. Protected areas also allow organisms to live and evolve in their natural environments.

28. Name two plants in India that have considerable religious significance.

Ans: The peepal tree and the tulsi plant.

29. What are the characteristics of biosphere reserves?

Ans: The characteristics of biosphere reserves are:

(i) They may include different ecosystems, such as mountains, plains, deserts, coastal regions, and marine environments. Each biosphere reserve represents one or more particular ecosystems.

(ii) Each biosphere reserve represents an ecosystem associated with a particular group of organisms and environmental conditions.

(iii) Each reserve helps conserve special forms of genetic diversity.

30. When is a species considered endangered?

Ans: A species is considered endangered when its population has declined considerably and it faces a high risk of extinction.

31. Mention two causes of mass extinction.

Ans: Two causes mentioned in the source are:

(i) The onset or advance of an ice age.

(ii) Excessive hunting of animals by humans.

32. What is the importance of genetic diversity?

Ans: Genetic diversity enables a species to survive under changing environmental conditions. It provides variations among individuals, allowing natural selection to favour those that are better adapted to their environment.

33. What is anthropogenic extinction?

Ans: Anthropogenic extinction is the complete disappearance of a species from the biosphere due to human activities.

34. What is the difference between species richness and species evenness?

Ans: Species richness refers to the number of different species present in a given area. Species evenness refers to how evenly individuals are distributed among those species in that area.

35. What are the main objectives of the Red Data List?

Ans: The main objectives of the Red Data List are:

(i) To identify threatened species and compile information about them.

(ii) To create public awareness about biodiversity.

(iii) To promote awareness of conservation at different levels.

C. Descriptive Questions (3–5 marks each)

36. Name the three components of biodiversity.

Ans: The three components of biodiversity are:

(i) Genetic diversity.

(ii) Species diversity.

(iii) Ecosystem diversity.

37. What are sacred groves? What is their role?

Ans: Sacred groves are parts of forests protected because of religious or cultural beliefs. In such areas, trees and other natural features are traditionally respected and protected.

Sacred groves help conserve many rare and threatened species found in these regions. Local communities often avoid destroying these forests, thereby helping to preserve biodiversity.

38. What are recalcitrant seeds?

Ans: Recalcitrant seeds are seeds that contain a relatively high amount of water and cannot tolerate drying or conventional long-term storage conditions. They are difficult to conserve using ordinary seed-storage methods.

39. What are the main objectives of UNESCO’s MAB programme?

Ans: The main objectives of the Man and the Biosphere (MAB) programme are:

(i) To promote the conservation and sustainable use of biosphere resources and improve the relationship between human beings and the environment.

(ii) To develop methods for predicting the environmental consequences of human activities and to improve knowledge and capacity for the sustainable use and conservation of natural resources.

(iii) To establish biosphere reserves as centres for research and training, where practical solutions to biodiversity conservation problems can be developed.

40. Why is biodiversity necessary for the functioning of an ecosystem?

Ans: Biodiversity is essential for the proper functioning of an ecosystem because it helps maintain ecological balance.

If biodiversity in an ecosystem is reduced, the loss of one organism may affect other organisms that depend on it. For example, if grass-like plants disappear from a forest, herbivores such as deer may lose their food source. If the deer population declines, predators such as tigers and lions may also be affected.

Thus, disturbances in a food chain can have harmful effects on many organisms. When an ecosystem contains a greater variety of species, organisms may have alternative food sources. This can help some organisms survive even when a particular food source becomes scarce.

41. What is a national park? Discuss its characteristics.

Ans: A national park is a legally protected area established to conserve wildlife, vegetation, and natural or historical features of national importance.

The characteristics of a national park are:

(i) It may contain different ecosystems, such as dense forests, grasslands, and wetlands, where various kinds of animals can live and move freely.

(ii) It provides opportunities to study wild animals and their natural habitats. It may also provide facilities for recreation and nature appreciation.

(iii) Activities such as hunting, building houses, grazing domestic animals, and farming are generally prohibited. Entry may be restricted or regulated, except for authorised research, management, and permitted visitor activities.

(iv) The natural environment is protected, and unnecessary alteration or artificial beautification is avoided.

(v) Access to sensitive core areas is restricted. Visitors may be permitted only in designated areas, depending on the rules of the park.

42. What are the major causes of species loss in a geographical region?

Ans: The major causes of species loss in a geographical region are:

(i) Habitat loss and fragmentation: Human activities change and destroy natural habitats. Examples include clearing forests for agriculture, destroying land for urbanisation, and filling wetlands. These activities threaten wildlife, and many species move towards extinction as a result.

(ii) Overexploitation: Humans may hunt or capture animals in quantities greater than their populations can sustain, often for commercial gain. This has caused the decline and extinction of many species.

(iii) Invasion by exotic species: The introduction of a new species into an ecosystem may cause native species to decline or disappear. For example, the introduction of the Nile perch into Lake Victoria in Africa contributed to the extinction of more than 200 species of native fish, according to the source text.

(iv) Co-extinction: In a natural ecosystem, one species may depend on another for survival. If one species becomes extinct, the species associated with it may also become extinct. For example, the extinction of a host species may lead to the extinction of its parasites.

43. Explain the rivet-popper hypothesis in relation to species extinction.

Ans: The rivet-popper hypothesis explains the importance of species diversity in maintaining the stability of an ecosystem. It uses the example of an aeroplane made up of many rivets.

Imagine that each passenger removes one rivet from the aeroplane. Removing a few rivets may not immediately affect the aeroplane’s ability to fly. However, if too many rivets are removed, the structure may become weak. If important rivets in a critical part, such as the wing, are lost, the aeroplane may become unable to fly safely.

Similarly, the extinction of a few species may not produce an immediately noticeable effect on an ecosystem. However, continued species loss can eventually cause serious damage to ecosystem functioning and stability.

44. Give and explain three hypotheses for the high species richness in tropical regions.

Ans: Tropical regions have the highest species richness. Three explanations are:

(i) Greater solar energy: Tropical regions receive more solar energy than many other regions. This supports higher biological productivity and contributes to greater species diversity.

(ii) Relatively stable climate: Seasonal variations in tropical regions are generally less pronounced, and environmental conditions remain comparatively stable. This may favour the development and persistence of a large number of species.

(iii) Historical stability: During ice ages, temperate regions were covered by extensive ice, whereas tropical regions were less affected. As a result, tropical organisms had more favourable conditions for survival and diversification over long periods.

45. What different methods can be adopted for biodiversity conservation?

Ans: Because of population growth and economic pressures, it is difficult to protect every ecosystem completely. Forests are increasingly cleared to create land for settlements and other human activities. Therefore, different approaches are used to conserve biodiversity.

The two main approaches described in the source are:

(i) In situ conservation: This means conserving species in their natural habitats. Areas that contain many native species and rich biodiversity are identified and protected from harmful human activities. This allows organisms to survive, reproduce, and evolve within their natural ecosystems.

(ii) Ex situ conservation: When a rare, endangered, or threatened species cannot be adequately protected in its natural habitat, it may be transferred to another location for conservation. Examples include botanical gardens, zoological parks, and other specialised facilities. Such organisms may be cared for and bred under scientific management. Modern methods include tissue culture, preservation of reproductive cells, cryopreservation at very low temperatures, and long-term seed storage.

D. Additional Questions and Answers

1. According to the current information given in the source, what percentage of the world’s flora is found in India?

Ans: Approximately 30%.

2. Why is an ecosystem with low biodiversity considered less stable?

Ans: An ecosystem with low biodiversity may have a limited ability to withstand disturbances and environmental changes. If one species disappears, organisms that depend on it may also be affected, and fewer alternative food sources or ecological functions may be available.

3. What are recalcitrant seeds?

Ans: Recalcitrant seeds are seeds that retain a high water content and are sensitive to drying. They cannot be stored easily using conventional seed-storage methods and may require special conservation techniques.

4. Write three hypotheses explaining the high species richness in tropical regions and briefly discuss them.

Ans: The three hypotheses are:

(i) Greater solar energy: Tropical regions receive more solar energy than temperate regions. This supports higher productivity and greater species diversity.

(ii) Climate stability: Seasonal variation is relatively low in tropical regions, so environmental conditions remain comparatively stable. This favours the survival of many species.

(iii) Historical stability: During ice ages, temperate regions were extensively covered by ice, whereas tropical regions were less affected. Tropical species therefore had more favourable conditions for survival and diversification.

5. Briefly describe three major tiger reserves in Assam.

Ans: The three tiger reserves described in the source are:

(i) Manas Tiger Reserve: The source states that Manas Tiger Reserve was established in 1973 for tiger conservation and covers an area of approximately 2,837 square kilometres across the districts of Kokrajhar, Chirang, Baksa, and Udalguri.

(ii) Nameri Tiger Reserve: The source states that Nameri Tiger Reserve was established in 2000 and covers approximately 344 square kilometres in Sonitpur district.

(iii) Kaziranga Tiger Reserve: The source identifies Kaziranga Tiger Reserve as another major tiger reserve in Assam, associated with Nagaon, Golaghat, and Sonitpur districts. The area figure is incomplete in the original text.

6. What are vulnerable species? Give examples.

Ans: Vulnerable species are species whose natural habitats are gradually shrinking and whose populations may still be relatively large, but which are at risk of becoming endangered if the factors causing their decline are not controlled in time.

Examples given in the source include the clouded leopard and the Assamese macaque.

7. What are the objectives of wildlife conservation?

Ans: The objectives of wildlife conservation are:

(i) To maintain ecological balance and ensure the sustainable, scientific, and well-planned use of renewable wildlife resources so that they remain available in the present and the future.

(ii) To ensure the protection and sustainable production of essential plant and animal resources.

(iii) To restore endangered populations through appropriate protection and management, thereby helping preserve the natural beauty of the Earth.

(iv) To protect rare organisms in their natural habitats and manage their breeding and population levels appropriately.

(v) To conserve biodiversity and protect genetic diversity for future generations.

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