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UPSC Prelims 2001 · Environment · Species Watch
Consider the following statements: Which of these are correct?
- Tapeworm is a hermaphrodite
- Round-worm has separate sexes
- Filaria is caused by a nematode
- Guinea-worm is an annelid
- (a) 1 and 2
- (b) 1, 2 and 3
- (c) 3 and 4
- (d) 2, 3 and 4
Show the answer and explanation
Answer: (b) 1, 2 and 3
Tapeworm hermaphrodite, roundworm separate sexes, filaria a nematode — all right.
Statement by statement
1. ✓ CORRECT Tapeworms (flatworms) are hermaphrodites — each segment has both organs.
2. ✓ CORRECT Roundworms (Ascaris) have separate male and female worms.
3. ✓ CORRECT Filariasis (elephantiasis) is caused by the nematode Wuchereria bancrofti.
4. ✗ WRONG The Guinea-worm (Dracunculus) is a nematode, not an annelid (annelids = earthworms, leeches).
The idea
Three unrelated groups are all called worms. Flatworms are flat and unsegmented. Roundworms (nematodes) are round, smooth and pointed at both ends. Segmented worms (annelids) have a body made of rings.
Flatworms: tapeworm, liver fluke → Roundworms: Ascaris, hookworm, filarial worm, guinea worm → Segmented worms: earthworm, leech
The trap
Its name has “worm” like the earthworm, but it is a roundworm.
Also know
Guinea worm disease comes from drinking water that contains tiny water fleas carrying the larvae; India was declared free of it in 2000. Filaria is spread by the Culex mosquito and causes swelling of the limbs (elephantiasis).
🔒 Guinea-worm = nematode (India declared free in 2000). Annelids = earthworm, leech.