Question

Define ammonotelic, ureotelic, and uricotelic animals. Give examples of each.

Answer 1

Ammonotelic animals:

1. An ammonotelic organism generally excretes nitrogenous waste as soluble ammonia.
2. Ammonia, the product or waste formed is highly toxic and requires a large amount of water for its excretion.
3. Most aquatic animals including protozoans, crustaceans, Platyhelminthes, cnidarians, poriferans, echinoderms, fishes, larvae/tadpoles of amphibians are ammonotelic.

Ureotelic animals:

1. A ureotelic organism generally excretes excess nitrogen as urea. Urea is less toxic and needs less water for excretion. The uricotelic organism excretes either uric acid or its salts.
2. Uric acid is the least toxic and requires less water in comparison to urea and ammonia. It can be stored in the cells and body tissues without causing any toxic effects.
3. Ureotelic organisms include cartilaginous fish, a few bony fishes, adult amphibians, and also mammals including humans.

Uricotelic animals:

1. The species which excrete uric acid waste are called uricotelic organisms.
2. The excreta of the uricotelic organisms are insoluble solids or semi-solid and requires less water.
3. For example: Terrestrial arthropods (including insects), lizards, snakes, birds, etc.