Biology

Biodiversity and Conservation

Question:

Of the four major causes for the loss of biodiversity (Alien species invasion, habitat loss and fragmentation, over-exploitation and co-extinctions which according to you is the major cause for the loss of biodiversity? Give reasons in support.

Answer:

Habitat loss and fragmentation is the most important cause driving animals and plants to extinction. The most dramatic examples of habitat loss come from tropical rain forests. Once covering more than 14 per cent of the earth's land surface, these rain forests now cover no more than 6 per cent. They are being destroyed fast. By the time you finish reading this chapter, 1000 more hectares of rain forest would have been lost. The Amazon rain forest (it is so huge that it is called the ‘lungs of the planet') harbouring probably millions of species is being cut and cleared for cultivating soyabeans or for conversion to grasslands for raising beef cattle.

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Biodiversity and Conservation

Q 1.

The species diversity of plants (22 per cent) is much less than that of animals (72 per cent).What could be the explanations to how animals achieved greater diversification?

Q 2.

What could have triggered mass extinctions of species in the past?

Q 3.

What are sacred groves? What is their role in conservation?

Q 4.

Name the three important components of  biodiversity.

Q 5.

Define gene pool.

Q 6.

What are the major causes of species losses in a geographical region ?

Q 7.

What is an endangered species? Give an example of an endangered plant and animal species each.

Q 8.

How can you, as an individual, prevent the loss of biodiversity?

Q 9.

How do scientists extrapolate the total number of species on Earth?

Q 10.

List any two major causes other than anthropogenic causes of the loss of biodiversity.

Q 11.

What is Red Data Book?

Q 12.

What does Red' indicate in the IUCN Red list (2004)?

Q 13.

How is the presently occurring species extinction different from the earlier mass extinctions?

Q 14.

Why are the conventional methods not suitable for the assessment of biodiversity of bacteria?

Q 15.

What is co-extinction? Explain with a suitable example.

Q 16.

Elaborate how invasion by an alien species reduces the species diversity of an area.

Q 17.

Though the conflict between humans and wildlife started with the evolution of man, the intensity of conflict has increased due to the activities of modem man. Justify your answer with suitable examples.

Q 18.

Of the four major causes for the loss of biodiversity (Alien species invasion, habitat loss and fragmentation, over-exploitation and co-extinctions which according to you is the major cause for the loss of biodiversity? Give reasons in support.

Q 19.

Is it true that there is more solar energy available in the tropics? Explain briefly.

Q 20.

Humans benefit from diversity of life. Give two examples.

Q 21.

What are sacred groves and their role in biodiversity conservation?

Q 22.

What is common to the species shown in figures A and B?
ncert-exemplar-problems-class-12-biology-biodiversity-conservation-7

Q 23.

Suggest a place where one can go to study coral reefs, mangrove vegetation and estuaries.

Q 24.

What is an ecosystem service? List any four important ecosystem services provided by the natural ecosystems. Are you in favour or against levying a charge on the service provided by the ecosystem?

Q 25.

Why is genetic variation important in the plant Rauwolfia vomitorial ?

Q 26.

What criteria should one use in categorizing a species as threatened?

Q 27.

What is common to the species shown in figures A and B?
ncert-exemplar-problems-class-12-biology-biodiversity-conservation-6

Q 28.

Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?

Q 29.

According to David Tilman, greater the diversity, greater is the primary productivity. Can you think of a very low diversity man-made ecosystem that has high productivity?

Q 30.

Give three hypothesis for explaining why tropics '”show greatest levels of species richness.

Q 31.

Is it possible that productivity and diversity of a natural community remain constant over a time period of, say one hundred years?

Q 32.

What characteristics make a community stable?

Q 33.

What does the term Frugivorous' mean?

Q 34.

How is biodiversity important for ecosystem functioning?

Q 35.

Match the animals given in column A with their location in column B.
ncert-exemplar-problems-class-12-biology-biodiversity-conservation-1
Choose the correct match from the following:
(a) i  ”A, ii ”C, iii B, iv D (b) i ”D, ii”C, iii ”A, iv”B
(c) i”C, ii”A, iii”B, iv”D (d) iâC, iiA, iii”D, iv”B

Q 36.

What is the significance of the slope of regression in a species – area relationship?

Q 37.

Among the ecosystem services are control of floods and soil erosion. How is this achieved by the biotic components of the ecosystem?

Q 38.

How do ecologists estimate the total number of species present in the world?

Q 39.

How does species diversity differ from ecological diversity?

Q 40.

Define the terms (i) Bioprospecting (ii) Endemism

Q 41.

What is the expanded form of IUCN?

Q 42.

The relation between species richness and area for a wide variety of taxa turns out to be a rectangular hyperbola. Give a brief explanation.

Q 43.

There is greater biodiversity in tropical /subtropical regions than in temperate region. Explain.

Q 44.

What is the difference between endemic and exotic species?

Q 45.

What could be the possible explanation for greater vulnerability of amphibians to extinction as compared to other animal groups?

Q 46.

Explain as to how protection of biodiversity hot spots alone can reduce up to 30% of the current rate of species extinction.  

Q 47.

Discuss one example, based on your day-to-day observations, showing how loss of one species may lead to the extinction of another.

Q 48.

Can you think of a scientific explanation, besides analogy used by Paul Ehrlich, for the direct relationship between diversity and stability of an ecosystem?

Q 49.

Explain briefly the ˜rivet popper hypothesis' of Paul Ehrlich.

Q 50.

What accounts for the greater ecological diversity of India?