Aquatic animals generally are ammonotelic in nature whereas terrestrial forms are not. Comment.
Ammonia is the most toxic form and requires large amount of water for its elimination, terrestrial adaptation necessitated the production of lesser toxic nitrogenous wastes like urea and uric acid for conservation of water. Mammals, many terrestrial amphibians and marine fishes mainly excrete urea and are called ureotelic animals. Ammonia produced by metabolism is converted into urea in the liver of these animals and released into the blood which is filtered and excreted out by the kidneys.