How have the terrestrial organisms adapted

The terrestrial mammals or even amphibians mainly excrete nitrogenous wastes in form of urea and hence are known as ureotelic organisms while reptiles, etc. excrete

nitrogenous wastes in form of uric acid and hence are called uricotelic organisms. Thus this is how the conversion of ammonia to urea or uric acid has been the

adaptation that the terrestrial organisms have gone through for conservation of water.