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UPSC CSE Prelims 2011 · GS paper

The Himalayan Range is very rich in species diversity. Which one among the following is the most…

A question from UPSC Civil Services (Preliminary) Examination 2011, General Studies, explained with its sources.

Prelims 2011 · archive

Easy

The Himalayan Range is very rich in species diversity. Which one among the following is the most appropriate reason for this phenomenon?

Answer & explanation

Answer: (b) It is a confluence of different biogeographical zones

The Himalaya lies in a transition zone where the Palaearctic realm meets the Indo-Malayan realm. Species from both realms are found there. This mixing has caused a proliferation of species, and it is the main reason for the range's richness.

  • ✗ (a) Rainfall differs widely across the Himalaya, from wet in the east to dry in the trans-Himalaya. So high rainfall cannot explain richness across the whole range. The richness comes from the meeting of different biogeographic realms, not from rainfall.
  • ✓ (b) The Himalaya straddles a transition zone between the Palaearctic and Indo-Malayan realms, and species from both are found there. This mixing of communities has caused a proliferation of species, which makes the range very rich in diversity.
  • ✗ (c) Exotic and invasive species are present in the Himalaya. In any case, the absence of introduced species would not by itself create species richness.
  • ✗ (d) The Himalaya is not free of human pressure; people settle, farm and use forests across the range. Less human interference may help species survive, but it does not explain why so many species are there in the first place.

Remember · The Himalaya is rich in species because it is a transition zone where the Palaearctic and Indo-Malayan biogeographic realms meet, so species from both realms are found there.

Sources

Question: UPSC Civil Services (Preliminary) 2011, General Studies paper. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). ·

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