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UPSC Prelims 2021 · Environment · Species Watch
Which of the following are detritivores? Select the correct answer using the code given below.
- Earthworms
- Jellyfish
- Millipedes
- Seahorses
- Woodlice
- (a) 1, 2 and 4 Only
- (b) 2, 3, 4 and 5 Only
- (c) 1, 3 and 5 Only
- (d) 1, 2, 3, 4 and 5
Show the answer and explanation
Answer: (c) 1, 3 and 5 Only
Earthworms, millipedes and woodlice eat detritus.
Statement by statement
1. ✓ YES Earthworms eat decaying plant matter in soil.
2. ✗ NO Jellyfish are predators that sting plankton and small fish.
3. ✓ YES Millipedes eat dead leaves and wood.
4. ✗ NO Seahorses are predators of tiny crustaceans.
5. ✓ YES Woodlice feed on decaying plant matter.
The idea
Detritus is dead plant and animal matter. A detritivore is an animal that eats it and breaks it into small pieces. A decomposer (bacteria and fungi) then breaks those pieces down chemically. The first prepares the work for the second.
Dead leaves fall → Earthworms, millipedes and woodlice chew them into fragments → Bacteria and fungi rot the fragments → Nutrients return to the soil
The trap
Slow, drifting sea animals look like scavengers. Jellyfish and seahorses hunt live prey.
Also know
A millipede eats dead leaves and is harmless; a centipede is a fast hunter with a poisonous bite. Woodlice are crustaceans that live on land. In the sea, the sea cucumber does the same job.
🔒 Detritivores: earthworms, millipedes, woodlice, dung beetles, sea cucumbers.