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100 questions in this collection · Page 9 of 10
Question 81 of 100
📘 CLASS XII
Biodiversity And Conservation
Read the following statements regarding the historical extinctions documented by the IUCN Red List (2004):
I. It documents the extinction of 784 species in the last 500 years. II. The list of extinct species is composed of 338 vertebrates, 359 invertebrates, and 87 plants. III. It highlights that the last 20 years alone have witnessed the disappearance of 27 species. IV. It shows that extinctions across different taxonomic groups occur in a completely random pattern.
Which of the statements given above are correct?
Statement IV is incorrect because extinctions across taxonomic groups are not random. Amphibians, for example, are especially vulnerable. Statements I, II and III are correct.
Question 82 of 100
📘 CLASS XII
Biodiversity And Conservation
Evaluate the following statements regarding the global threat of extinction across major taxonomic groups:
I. More than 15,500 species worldwide are currently facing the threat of extinction. II. Among these, 12 per cent of all mammal species and 23 per cent of all bird species face extinction. III. Presently, 32 per cent of all amphibian species and 31 per cent of all gymnosperm species face the threat of extinction.
Which of the statements given above are correct?
Statement II is incorrect because the percentages are reversed. About 12% of bird species and 23% of mammal species are threatened. Statements I and III are correct.
Question 83 of 100
📘 CLASS XII
Biodiversity And Conservation
Consider the following statements about the "Evil Quartet" driver – habitat loss and fragmentation:
I. Habitat loss and fragmentation is the most important cause driving animals and plants to extinction. II. Tropical rain forests once covered more than 14 per cent of Earth's land surface, but now cover no more than 6 per cent. III. When large habitats are broken up into small fragments due to human activities, mammals and birds requiring large territories and certain animals with migratory habits are badly affected. IV. Soya bean cultivation and clearing for beef cattle grasslands are key drivers of Amazon rain forest destruction.
Which of the statements given above are correct?
Habitat loss and fragmentation is the single most important cause of extinction. Tropical rain forests have declined from over 14% to less than 6% of Earth's land area. Habitat fragmentation severely affects territorial and migratory animals, while Amazonian deforestation is largely driven by soybean cultivation and conversion into cattle-grazing lands.
Question 84 of 100
📘 CLASS XII
Biodiversity And Conservation
With reference to the "Evil Quartet" driver – alien species invasions, study the following statements:
I. The Nile perch was introduced into Lake Victoria in east Africa and led to the extinction of over 200 species of cichlid fish. II. Invasive weed species in India like Parthenium (carrot grass), Lantana, and Eichhornia (water hyacinth) pose severe threats to native species. III. The illegal introduction of the African catfish Clarias gariepinus for aquaculture is posing a threat to the indigenous catfishes in our rivers. IV. Introduction of alien species always results in the immediate co-extinction of obligate pollinators.
Which of the statements given above are correct?
Statement IV is incorrect because co-extinction refers to the loss of dependent species when a host species becomes extinct, and is not a direct consequence of every alien species invasion. Statements I, II, and III are correct textbook examples of invasive alien species causing ecological disruption.
Question 85 of 100
📘 CLASS XII
Biodiversity And Conservation
Consider the following statements regarding international biodiversity summits and agreements:
I. The Convention on Biological Diversity ('The Earth Summit') was held in Johannesburg, South Africa, in 1992. II. The World Summit on Sustainable Development was held in Rio de Janeiro, Brazil, in 2002. III. At the 2002 World Summit, 190 countries pledged to achieve a significant reduction in the current rate of biodiversity loss by 2010.
Which of the statements given above are correct?
Statements I and II are incorrect because the locations are interchanged. The Earth Summit was held at Rio de Janeiro (1992), while the World Summit on Sustainable Development was held at Johannesburg (2002). Statement III is correct.
Question 86 of 100
📘 CLASS XII
Biodiversity And Conservation
Read the following statements regarding the categorization of conservation arguments:
I. Broadly utilitarian arguments focus on direct economic benefits like food, firewood, and pharmaceuticals. II. Narrowly utilitarian arguments focus on ecosystem services like oxygen production, pollination, and aesthetic pleasures. III. The ethical argument states that every species has an intrinsic value and we have a moral duty to care for them and pass on our biological legacy.
Which of the statements given above is/are correct?
Statements I and II are incorrect because the definitions are reversed. Narrowly utilitarian arguments involve direct economic benefits, whereas broadly utilitarian arguments include indirect ecosystem services. Statement III correctly describes the ethical argument.
Question 87 of 100
📘 CLASS XII
Biodiversity And Conservation
Study the following statements regarding in situ conservation – biodiversity hotspots:
I. Biodiversity hotspots are characterized by very high levels of species richness and a high degree of endemism. II. Currently, there are 34 biodiversity hotspots in the world. III. Three hotspots cover our country’s exceptionally high biodiversity regions: Western Ghats and Sri Lanka, Indo-Burma, and Himalaya. IV. Put together, all biodiversity hotspots cover more than 10 per cent of Earth's land area.
Which of the statements given above are correct?
Statement IV is incorrect because biodiversity hotspots together occupy less than 2% of the Earth's land area. Statements I, II, and III are correct.
Question 88 of 100
📘 CLASS XII
Biodiversity And Conservation
With reference to in situ conservation structures in India, evaluate these statements:
I. India's legally protected in situ conservation network includes 14 biosphere reserves, 90 national parks, and 448 wildlife sanctuaries. II. Sacred groves in India provide a form of ex situ conservation in highly commercialized forestry zones. III. Sacred groves include Khasi and Jaintia Hills in Meghalaya, Aravalli Hills in Rajasthan, Western Ghats in Karnataka and Maharashtra, and Sarguja, Chanda, and Bastar areas of Madhya Pradesh.
Which of the statements given above are correct?
Statement II is incorrect because sacred groves represent an in situ conservation practice where biodiversity is protected in its natural habitat. Statements I and III are correct.
Question 89 of 100
📘 CLASS XII
Biodiversity And Conservation
Consider the following statements about advanced ex situ conservation techniques:
I. Ex situ conservation is an off-site approach desirable when an organism faces a very high risk of extinction in the wild in the near future. II. Gametes of threatened species can be preserved in viable and fertile conditions for long periods using cryopreservation. III. Seed banks keep seeds of different genetic strains of commercially important plants for short periods, usually no longer than one month.
Which of the statements given above are correct?
Statement III is incorrect because seed banks preserve seeds for long periods. Statements I and II correctly describe ex situ conservation and cryopreservation.
Question 90 of 100
📘 CLASS XII
Biodiversity And Conservation
Read the following statements regarding the proportion of taxonomic groups in global biodiversity:
I. Animals comprise more than 70 per cent of all recorded species on Earth. II. Plants (including algae, fungi, bryophytes, gymnosperms, and angiosperms) comprise no more than 22 per cent of the total. III. Among animals, insects make up more than 70 per cent of the total. IV. Fungi species in the world outnumber the combined total species of fishes, amphibians, reptiles, and mammals.
Which of the statements given above are correct?
All four statements are correct. Animals constitute over 70% of described species, plants (including algae, fungi, bryophytes, gymnosperms, and angiosperms) comprise no more than 22%, insects account for over 70% of all animal species, and fungi outnumber the combined species of fishes, amphibians, reptiles, and mammals.