Question

What are ammonotelic and ureotelic animals? Give examples.

Answer 1

Hint: Different animals excrete different excretory products.

Complete answer:
Ammonotelic Animals:-
1) The process of formation of excretory products in the form of ammonia is called ammonotelism; thus organisms showing ammonotelism are called ammonotelic animals.
2) As ammonia is highly toxic but readily soluble in water, is generally excreted by simple diffusion across body surfaces or through gill surfaces to avoid harmful effects.
3) As a large quantity of water is required for its elimination (300-500ml of water for 1 gram of ammonia), it is seen in aquatic insects, aquatic amphibians, bony fishes, tadpole larva of frog.

Ureotelic Animals:-
1) The process of elimination of excretory products in the form of urea is called ureotelism; thus organisms showing ureotelism are called ureotelic animals.
2) Urea is relatively less toxic than ammonia, it can be stored for some time and excreted at a lower rate.
3) As a moderate amount of water is required for elimination of urea (50ml of water for 1 gm of urea), it is seen in terrestrial amphibians (toads, frogs), mammals and marine fishes.

Note: Ammonia is a highly toxic excretory product followed by urea and uric acid respectively, thus energy requirement for production of uric acid is more (inosine pathway) followed by urea (ornithine cycle) and ammonia (deamination) respectively.