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100 questions in this collection · Page 2 of 10
Question 11 of 100
📘 CLASS XII
Biodiversity And Conservation
According to predictions based on Robert May's global estimates, how many species are estimated to be yet discovered in India?
I. More than 1,00,000 plant species. II. More than 3,00,000 animal species. III. Approximately 45,000 plant species and 90,000 animal species.
Which of the statements given above are correct regarding the species waiting to be discovered?
Statements I and II are correct. More than 1,00,000 plant species and over 3,00,000 animal species are estimated to remain undiscovered in India. Statement III refers to species already recorded.
Question 12 of 100
📘 CLASS XII
Biodiversity And Conservation
Consider the following statements about the rate of biodiversity loss:
I. Nature's biological library is burning even before we catalogued the titles of all the books stocked there. II. If the present rates of species losses continue, we could lose all of Earth's biological wealth in less than two centuries. III. It took millions of years of evolution to accumulate this rich diversity.
Which of the statements given above are correct?
All three statements are correct. Biodiversity accumulated over millions of years of evolution, yet current extinction rates could eliminate much of it within two centuries.
Question 13 of 100
📘 CLASS XII
Biodiversity And Conservation
Consider the following statements regarding the global distribution of biodiversity:
I. Biodiversity is uniformly distributed throughout the world. II. Species diversity decreases as we move away from the equator towards the poles. III. Tropics (23.5° N to 23.5° S) harbour more species than temperate or polar regions.
Which of the statements given above are correct?
Statement I is incorrect because biodiversity is unevenly distributed across the globe. Statements II and III are correct as species diversity declines from the equator towards the poles, with the tropics harbouring the greatest diversity.
Question 14 of 100
📘 CLASS XII
Biodiversity And Conservation
Study the species counts of birds across different latitudinal locations:
I. Colombia, located near the equator, has nearly 1,400 species of birds. II. New York at 41° N has 105 species of birds. III. Greenland at 71° N has 56 species of birds. IV. India, with much of its land in tropical latitudes, has more than 1,200 species of birds.
Which of the statements given above are correct?
All four statements are correct and illustrate the latitudinal gradient in biodiversity. Bird species richness declines from equatorial regions towards higher latitudes.
Question 15 of 100
📘 CLASS XII
Biodiversity And Conservation
Consider the comparisons of species diversity in tropical and temperate regions:
I. A forest in a tropical region like Ecuador has up to 10 times as many species of vascular plants as a forest of equal area in the temperate Midwest of the USA. II. The largely tropical Amazonian rain forest in South America has the greatest biodiversity on Earth. III. Scientists estimate that the Amazonian rain forest may contain at least two million insect species waiting to be discovered and named.
Which of the statements given above are correct?
All three statements are correct. Tropical forests possess much greater biodiversity than temperate forests, the Amazon rainforest has the highest biodiversity on Earth, and an estimated two million insect species may still remain undiscovered there.
Question 16 of 100
📘 CLASS XII
Biodiversity And Conservation
Consider the following statements regarding the hypotheses explaining why the tropics show greater species richness:
I. Speciation is generally a function of time. II. Unlike temperate regions which were subjected to frequent glaciations in the past, tropical latitudes have remained relatively undisturbed for millions of years. III. The long, undisturbed evolutionary time in tropical regions was highly detrimental to species diversification, causing slow extinction of ancestral taxa.
Which of the statements given above are correct?
Statement III is incorrect. The long, undisturbed evolutionary history of tropical regions promoted species diversification rather than hindering it. Statements I and II are correct.
Question 17 of 100
📘 CLASS XII
Biodiversity And Conservation
Read the following statements about tropical environments and their role in biodiversity:
I. Tropical environments, unlike temperate ones, are highly seasonal, relatively constant, and highly unpredictable. II. Relatively constant and predictable environments promote niche specialisation. III. Increased niche specialisation in the tropics directly leads to a greater species diversity.
Which of the statements given above are correct?
Statement I is incorrect because tropical environments are less seasonal and more constant and predictable than temperate regions. Statements II and III are correct.
Question 18 of 100
📘 CLASS XII
Biodiversity And Conservation
With reference to solar energy and productivity in tropical latitudes, evaluate the following statements:
I. There is more solar energy available in the tropics. II. High solar energy availability contributes directly to a lower rate of ecosystem productivity. III. Higher productivity in the tropics contributes indirectly to greater species diversity.
Which of the statements given above are correct?
Statement II is incorrect because greater solar energy results in higher ecosystem productivity, which indirectly contributes to greater species diversity. Statements I and III are correct.
Question 19 of 100
📘 CLASS XII
Biodiversity And Conservation
Consider the following statements regarding the history and discovery of the species-area relationship:
I. The relationship was observed by the great German naturalist and geographer Alexander von Humboldt. II. Humboldt performed pioneering and extensive explorations in the wilderness of African deserts. III. He observed that within a region, species richness increased with increasing explored area, but only up to a limit.
Which of the statements given above are correct?
Statement II is incorrect because Alexander von Humboldt carried out his pioneering explorations in the South American jungles, not African deserts. Statements I and III are correct.
Question 20 of 100
📘 CLASS XII
Biodiversity And Conservation
Study the mathematical relationship between species richness and area:
I. For a wide variety of taxa, the relation between species richness and area on a normal scale is a rectangular hyperbola. II. On a logarithmic scale, the relationship is a straight line described by the equation log S = log C + Z log A. III. In this equation, S = species richness, A = area, Z = Y-intercept, and C = slope of the line (regression coefficient).
Which of the options represents the correct statements?
Statement III is incorrect because Z is the slope (regression coefficient) and C is the Y-intercept. Statements I and II are correct.