The process of excreting nitrogenous waste in the form of ammonia is termed ammonotelic. The phenomena is recognized as Ammonotelism. Birds, amphibians, reptiles, most of the aquatic animals, including fishes, some terrestrial invertebrates, larvae, and mammals including humans excrete urea acid as waste.
In this article will read about ammonotelic, ureotelic and uricotelic animals.
An ammonotelic organism excretes nitrogenous waste as soluble ammonia. Ammonia the product or waste formed is highly toxic. Highly-soluble, therefore needs plenty of water for its excretion
Most of the aquatic animals including protozoans, crustaceans, platyhelminths, cnidarians, poriferans, echinoderms, fishes, larvae/tadpoles of amphibians are ammonotelic.
A ureotelic organism excretes excess nitrogen as urea. Urea is less toxic and needs less water in comparison to Ammonia. The uricotelic organism excretes uric acid or its salts. In contrast to Ammonia and Urea, Uric acid is the least toxic and the most limited soluble in water. It can be stored in cells and body tissues without toxic effects and thus needs the least water and is a highly efficient mode of excretion in comparison to two other methods.
Ureotelic organisms include cartilaginous fish, few bony fishes, adult amphibians and mammals including humans.
The species that excrete uric acid waste are called uricotelic organisms. The excreta of uricotelic organisms is typically white paste and insoluble solids or semi-solid. Needs very little water just to flush out the uric acid
Uricotelic organisms include terrestrial arthropods (including insects), lizards, snakes, and birds.