CBSE Class 12 Biology Biodiversity And Conservation Worksheet Set C

Very Short Answer Questions

Question. Name the type of biodiversity represented by the following:
(i) 50,000 different strains of rice in India
(ii) Estuaries and alpine meadows in India. 
Answer. (i) Genetic diversity
(ii) Ecological diversity

Question. Name the unlabelled areas ‘a’ and ‘b’ of the pie chart representing biodiversity of vertebrates showing the proportionate number of species of major taxa
Answer. a → Fishes;
b → Amphibians.

Question. Write the importance of cryopreservation in conservation of biodiversity. 
Answer. By cryopreservation, the reproductive parts of rare species can be preserved.

Question. Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?
Answer. Species which are harmful to human beings can be made extinct, e.g., HIV, polio virus, etc. Such micro-organisms are not part of any food chain and thus, their extinction would not affect the ecosystem.

Question. What are seed banks? 
Answer. The collection of seeds of many different genetic strains of commercially important plants, that are kept viable for longer periods in place are called seed banks.

Question. What is the difference between endemic and exotic species? 
Answer. Endemic species are native species restricted to a particular geographical region. Exotic species are species which are introduced from other geographical regions into an area.

Question. Name the alien fish species which is posing a threat to the indigenous catfishes in our rivers.
Answer. Clarias gariepinus (African catfish)

Short Answer Questions

Question. What is IUCN red list? Give any two uses of this list.
Answer. IUCN red list is a catalogue of species and subspecies that are facing the risk of extinction.
The two uses of this list are:
(i) Provides information and develops awareness about the importance of threatened species.
(ii) Identification and documentation of endangered species and so measures can be taken for their protection.

Question. A particular species of wild cat is endangered. In order to save them from extinction, which is a desirable approach in situ or ex situ? Justify your answer and explain the difference between the two approaches. 
Answer. Ex situ is a desirable approach to protect the wild cat. The organism is protected outside their natural habitat where special care is taken to protect them. By using cryopreservation techniques,gametes of threatened species can also be preserved under very low temperature.
For difference, QU Biodiversity can be conserved by protecting its whole ecosystem.
QU There are two basic approaches for conservation of biodiversity.

Question. Is it true that there is more solar energy available in the tropics? Explain briefly.
Answer. As one moves from the equator to the polar regions, the length of the day decreases and the length of the night increases. The length of day and night are same at the equator.
Therefore, it is true that there is more solar energy available in the tropics.

Question. State the use of biodiversity in modern agriculture. 
Answer. Biodiversity is a source of hybrids, GM plants, biopesticides, organic farming, biofertiliser, improved varieties of plants, disease resistant plants. (Any two).

Question. List any four techniques where the principle of ex situ conservation of biodiversity has been employed.
Answer. Cryopreservation, in vitro fertilisation, micropropagation/tissue culture, sperm bank/seed bank/gene bank.

Question. In an experiment, the slope of regression (Z) is 0.2 and in another experiment the value obtained is 1.2. Explain the two situations in respect of species area relationships.
Answer. 0.2 is obtained in studies regardless of the taxonomic group and the region 1.2 is obtained if species area relationship is analysed among very large areas like the entire continents. 

Question. Would the extinction of one insect pollinator affect the ecosystem? Explain. 
Answer. It would affect the ecosystem because insect pollinators form a part of food web. It may lead to coextinction of species in the case of a co-evolved plant. It is a case of mutualism where extinction of one invariably leads to the extinction of the other.

Question. Among the ecosystem services are control of floods and soil erosion. How is this achieved by the biotic components of the ecosystem?
Answer. Control of soil erosion: Plant roots hold the soil particles tightly and do not allow the top soil to be drifted away by winds or moving water. Plants increase the porosity and fertility of the soil.
Control of floods: It is carried out by retaining water and preventing run off of rain water. Litter and humus of plants function as sponges thus retaining the water which percolates down and get stored as underground water. Hence, the flood is controlled.

Question. What is cryopreservation? Give its one use.
Answer. Cryopreservation is a preservation technique in which sperms, eggs, cells, tissues, etc., are stored at ultra-low temperature of −196ºC under nitrogen. Cells and gametes of threatened species can also be preserved by this method.

Long Answer Questions

Question. There are many animals that have become extinct in the wild but continue to be maintained in Zoological parks.
(i) What type of biodiversity conservation is observed in this case?
(ii) Explain any two other ways which help in this type of conservation. 
Answer. (i) Ex-situ conservation
(ii) (a) In-vitro fertilisation: Gametes of threatened species can be fertilised for their propagation.
(b) Cryopreservation techniques: Gametes of threatened species can be preserved in viable and fertile condition for long periods.

Question. Compare narrowly utilitarian and broadly utilitarian approaches to conserve biodiversity, with the help of suitable examples.
Answer. (i) Narrowly utilitarian arguments
OU Human beings derive direct economic benefits from nature, like food, firewood, fibre, construction material, industrial products (resins, gums, dyes, tannins, etc.) and medicinally important products.
• More than 25 per cent of the drugs are derived from plants and about 25,000 species of plants are used by native people as traditional medicines.
(ii) Broadly utilitarian arguments
• Biodiversity plays a major role in maintaining and sustaining supply of goods and services from various species as well as ecological systems.
• The different ecological services provided are:
(a) Amazon forest is estimated to contribute 20 per cent of the total oxygen in the atmosphere on earth by photosynthesis.

Question. Many plant and animal species are on the verge of their extinction because of loss of forest land by indiscriminate use by the humans. As a biology student what method would you suggest along with its advantages that can protect such threatened species from getting extinct?
Answer. Ex situ conservation method can be used. Refer to Basic Concepts Point 8 (ii).

Question. Name and describe any three causes of biodiversity losses. 
Answer. (i) Habitat loss and fragmentation
• Destruction of habitat is the primary cause of extinction of species.
(ii) Over-exploitation
• When biological system is over-exploited by man for the natural resources, it results in degradation and extinction of the resources.
(iii) Alien (exotic) species invasions
• Some alien (exotic) species when introduced unintentionally or deliberately, become invasive and cause harmful impact, resulting in extinction of the indigenous species.
(iv) Co-extinctions
• When a species becomes extinct, the plant and animal species associated with it in an obligatory manner, also become extinct.

 

Question. log S = log C + Z log A In the given equation of species-area relationship, the value of regression coefficient for a whole continent, would be

(a) 0.1-0.2

(b) 0.5-0.7

(c) 0.6-1.2

(d) 0.3-0.5

 

Question. Which of the following organisation is responsible for maintaining the Red Data Book?

(a) IDRI

(b) IUCN

(c) UNESCO

(d) USDA

 

Question. From his long term ecosystem experiments, David Tilman showed that

(a) decreased diversity contributed to higher productivity

(b) decreased diversity contributed to decreased productivity

(c) increased diversity contributed to increased productivity

(d) increased diversity contributed to decreased productivity

 

Question. Which of the following is a hot-spot of biodiversity in India?

(a) Western Ghats

(b) Indo-gangetic plain

(c) Eastern Ghats

(d) Aravalli Hills

 

Question. Which among the following is not a method of in-situ conservation?

(a) National Park

(b) Botanical garden

(c) Wildlife sanctuary

(d) Ramsar sites

 

Question. The World Summit on Sustainable Development (2002) was held in

(a) Brazil

(b) South Africa

(c) Sweden

(d) Argentina

 

Question. The most important cause of extinction of animals and plants, especially in tropical rain forests is

(a) habitat loss

(b) afforestation

(c) pollution

(d) soil erosion

 

Question. The enormous number of varieties of mango in India represents

(a) genetic diversity

(b) species diversity 1

(c) ecological diversity

(d) hybridisation programmes

 

Question. Which one of the following is not a major characteristic feature of biodiversity hot spots?

 

(a) Large number of species

(b) Abundance of endemic species

(c) Large number of exotic species

(d) Destruction of habitat

 

Question. Which of the following is not a cause for loss of biodiversity?

(a) Destruction of habitat

(b) Invasion by alien species

(c) Keeping animals in zoological parks

(d) Over-exploitation of natural resources

 

Question. The extinction of passenger pigeon was due to

(a) increased number of predatory birds.

(b) over exploitation by humans.

(c) non-availability of the food.

(d) bird flu virus infection.

 

Question. Which of the below mentioned regions exhibit less seasonal variations?

(a) Tropics

(b) Temperates

(c) Alpines

(d) Both (a) & (b)

 

14. 70 per cent of the animal species recorded are _____ .

15. ________ places the global species biodiversity at about 7 million.

16. The maximum diversity of amphibians in India is observed in _____ .

17. The recent introduction of Clarias gariepinus is posing threat to our indigenous _____ in our rivers.

18. _____ introduced into Lake Victoria caused extinction of 200 species of cichlid fishes.

19. Thylacine from _____ and quagga from Africa are examples of recent extinctions.

20. _____ popularised the term Biodiversity.

21. India’s share of global biodiversity is about _____ per cent.

22. _____, the last refuges of a number of threatened species of plants, are found in Aravalli Hills of Rajasthan and Jaintia Hills of Meghalaya.

23. Match the items in Column I with those in Column II.

24. Match the items in Column I with those in Column II.

25. Parthenium is an endemic species of our country. [True/False]

26. Stellar’s sea cow is an extinct animal. [True/False]

27. India is one of the mega diversity countries of the world. [True/False]

28. 20 per cent of the total oxygen in the earth’s atmosphere is produced by temperate forests like Amazon forest. [True/False]

29. Endemic species are those which are distributed in almost all parts on the globe. [True/False] Directions (Q30 to Q33): Mark the odd one in each of the following groups.

30. Parthenium, Mangifera, Lantana Eichhornia

31. Bali, Javan, Caspian, Dodo

32. Seed banks, Tissue culture, Sacred groves, Cryopreservation

33. Aravalli Hills, Chanda and Bastar, Khasi Hills, Zoological park

34. Name the type of biodiversity represented by the following:
(a) 50,000 different strains of rice in India.
(b) Estuaries and alpine meadows in India. 

Or

India has more than 50,000 strains of rice. Mention the level of biodiversity it represents. 

35. Name the type of biodiversity represented by the following:
(a) 1000 varieties of mango in India.

(b) Variations in terms of potency and concentration of reserpine in Rauwolfia vomitoria growing in different regions of Himalayas. 

36. Write the level of biodiversity represented by a mangrove. Give another example falling in the same level. 

37. Why is genetic variation important in the plant Rauwolfia?

38. Why is India said to have greater ecosystem diversity than Norway? 

39. Define species diversity..

40. Which region in India has the maximum number of amphibian species?

Please click on below link to download CBSE Class 12 Biology Biodiversity And Conservation Worksheet Set C