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Modes of Excretion
Concepts tested here
- Excretion depends on water availability
All Questions
2006 AIPMT-PRE 1 question
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Earthworms are -The nature of the nitrogenous waste excreted by an animal depends on the availability of water.
Ammonia is highly toxic and needs a large amount of water for its removal, so it is excreted when water is plentiful.
Earthworms live in moist soil. When plenty of water is available, they excrete mainly ammonia, i.e. they are ammonotelic.
When water is scarce, in drier conditions, they change over to excreting mainly urea, i.e. they become ureotelic, since urea is less toxic and needs less water.
They are not uricotelic under either condition.
So earthworms are ammonotelic when plenty of water is available.