Question 14 of 18intermediate💡 UnderstandShort Answer3 marks

Give three hypotheses for explaining why tropics show greatest levels of species richness.

Correct Answer

The three hypotheses explaining why tropics show the greatest levels of species richness are:

1. More evolutionary time: The tropics had more evolutionary time for speciation to occur compared to temperate regions, allowing greater diversification of species over geological time.

2. Relatively constant environment: The tropics provide a relatively constant and stable environment with less seasonal variation, which supports the survival and coexistence of more species.

3. Greater solar energy and productivity: Tropics receive more solar energy throughout the year, which contributes to greater productivity. This higher productivity supports larger populations and more species in the ecosystem.

Exercise: EXERCISES | Q: 3 | (Page 11)
For More Understanding

Explanation

According to the NCERT textbook, species diversity on earth is not uniformly distributed - it is generally highest in the tropics and decreases towards the poles. The textbook explicitly lists three important explanations for this pattern: (1) Tropics had more evolutionary time, (2) they provide a relatively constant environment, and (3) they receive more solar energy which contributes to greater productivity. These three points should be presented clearly for the 3-mark question.

Solution Steps

  1. Step 1: Identify the question asks for three hypotheses about tropical species richness

  2. Step 2: Extract the three explanations directly from the context provided

  3. Step 3: Present each hypothesis with proper emphasis on key terms using bold formatting

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