Excretary System in Animals - Part - I

Metabolic activities in the animals produce some nitrogen containing waste products. These are called as nitrogenous wastes. Elimination of these nitrogenous wastes is called - Excretion.
Animals usually excrete these nitrogenous wastes in three forms. They are Ammonia, Urea and Uric acid. Animals which eliminate their nitrogenous wastes in the form of Ammonia are called 'Ammonotelic animals', and the process is called Ammonotelism.Ex. Aquatic Invertebrates, Bony fishes, Larvae of Amphibians etc. Animals which eliminate their nitrogenous wastes in the form of Urea are called 'Ureotelic animals', and the process is called Ureotelism. Ex. Cartilaginous fishes, Adult amphibians and Mammals. Animals that excrete their nitrogenous wastes in the form of Uric acid are called 'Uricotelic animals', and the process - Uricotelism. Ex. Insects, Reptiles and Birds.