UPSC Prelims 2018 Q87: Environment & Ecology – Ecosystems & Ecology Concepts
- (a) 1 and 2 only
- (b) 3 only
- (c) 1 and 3 only
- (d) 1, 2 and 3
Answer: (d) 1, 2 and 3
Explanation
Coral Reefs - Ecological Facts
| Statement | Claim | Verdict | Detail |
|---|---|---|---|
| 1 | Most of the world's coral reefs are in tropical waters | TRUE | Reef-building corals require warm (18-30 C), shallow, sunlit, clear waters - concentrated in tropical seas between 30 N and 30 S latitudes. |
| 2 | More than 1/3rd of world's coral reefs are in Australia + Indonesia + Philippines | TRUE | Australia hosts the Great Barrier Reef (world's largest). The Coral Triangle (Indonesia, Philippines, Malaysia, PNG, Solomon Islands, Timor-Leste) holds ~30% of world's reefs. Australia + Indonesia + Philippines together account for over 1/3rd of global coral reefs. |
| 3 | Coral reefs host far more animal phyla than tropical rainforests | TRUE | Coral reefs contain representatives of virtually every animal phylum (~32), while rainforests are dominated by insects and vertebrates (~9-10 phyla). By phyla count, reefs are more phylogenetically diverse than rainforests. |
Answer: (d) 1, 2 and 3.
Why each option is right or wrong
- (a) Incorrect. Statement 3 is also correct - coral reefs host more animal phyla than rainforests.
- (b) Incorrect. Statements 1 and 2 are also correct.
- (c) Incorrect. Statement 2 (Australia/Indonesia/Philippines share) is also correct.
- (d) CORRECT. All three statements about coral reef distribution and biodiversity are correct.
Key point
Coral reef facts: Concentrated in tropical warm shallow clear waters (30 N to 30 S). Coral Triangle (Indonesia, Philippines + 4 others) = 30%+ of world reefs. Reefs host ~32 animal phyla (vs ~9-10 in rainforests) - highest phyla diversity of any ecosystem.
Remember
Most of the world's coral reefs are in tropical waters, and over one-third are located in Australia, Indonesia and the Philippines (part of the biodiverse Coral Triangle). Coral reefs host representatives of far more animal phyla (about 32) than tropical rainforests (about 9-10), making them the most phylogenetically diverse ecosystems on Earth.
Common mistakes
- Believing rainforests have more biodiversity than reefs - by species count perhaps, but by phyla count reefs surpass them.
- Missing the Coral Triangle - the marine equivalent of Amazon in biodiversity concentration.
- Assuming coral reefs are in cold waters - they need warm (18-30 C), sunlit shallows, exclusively tropical.
Exam tip
Coral reef distribution: Tropical shallow warm seas. Global heavyweights: Australia (Great Barrier), Coral Triangle (Indonesia/Philippines), Caribbean, Red Sea, Indian Ocean atolls (Maldives, Lakshadweep). Threatened by warming, acidification, bleaching.
Sources
- IUCN - Status of the World's Coral Reefs (Global Coral Reef Monitoring Network)
- NCERT Class 11 Biology - Ecosystems and Biodiversity