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Question
Give three hypotheses for explaining why tropics show greatest levels of species richness.
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Solution
- Speciation is generally a function of time. Temperate regions have been repeatedly glaciated since ancient times, while tropical latitudes have remained undisturbed for millions of years. Hence, there has been more time for species to evolve and diversify.
- The tropical environment is different from the temperate environment and shows fewer seasonal changes. This stable environment has encouraged niche specialisation, leading to greater species diversity.
- More solar energy is available in tropical regions, which leads to greater productivity and, indirectly, to more extraordinary biodiversity.
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RELATED QUESTIONS
The following graph shows the species-area relationship. Answer the following questions as directed.
(a) Name the naturalist who studied the kind of relationship shown in the graph. Write the observations made by him.
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(c) When would the slope of the line ‘b’ become steeper?
Explain, giving three reasons, why tropics show greatest levels of species diversity.
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| Column I | Column II | ||
| i. | Alexander Van Humboldt | a. | Estimated 7 million species round the globe |
| ii. | Robert May | b. | Rivet popper hypothesis |
| iii. | David Tillman | c. | Species Area Relationship |
| iv. | Paul Ehrlich | d. | Productivity stability hypothesis |
