UPSC Prelims 2018 · Question 87 of 99

UPSC Prelims 2018 question on Coral Reefs Distribution

Consider the following statements:

1. Most of the world's coral reefs are in tropical waters.

2. More than one-third of the world's coral reefs are located in the territories of Australia, Indonesia and Philippines.

3. Coral reefs host far more number of animal phyla than those hosted by tropical rainforests.

Which of the statements given above is/are correct?

  1. 1 and 2 only
  2. 3 only
  3. 1 and 3 only
  4. 1, 2 and 3
Show answer

Answer: D. 1, 2 and 3

Verdict

All three statements are correct, so the answer is (d) 1, 2 and 3.

Statement by statement

Statement 1 is CORRECT. Most coral reefs are located in tropical shallow waters less than 50 metres deep, in the western Indian Ocean, the Pacific and the Greater Caribbean.

Statement 2 is CORRECT. In the global distribution of corals, Australia holds about 17 percent, Indonesia about 16 percent and the Philippines about 9 percent, so together they host more than one-third of the world's corals.

Statement 3 is CORRECT. Coral reefs host 32 of the 34 recognised animal phyla, compared with only 9 phyla in tropical rainforests.

Source

Coral Reef Alliance resource on coral reef geography.

How to crack it

Statement 3 is the one that feels wrong, because rainforests are the standard emblem of biodiversity. The unlock is that phyla count body plans rather than species, and marine environments hold far more distinct body plans than terrestrial ones, even though rainforests hold more species. Distinguish the measure of diversity being used before judging such a claim, since species richness and phylum diversity give opposite answers here.

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