How have the terrestrial organisms adapted themselves for conservation of water?
Terrestrial adaptation necessitated the production of lesser toxic nitrogenous wastes like urea and uric acid for the conservation of water Mammals and many terrestrial amphibians 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. Some urea is retained in the kidney in order to maintain osmolarity reptiles birds, land snails and insects excrete nitrogenous waste, as uric acid in the form of a pellet or paste with a minimum loss of water and are called uricotelic animals. Conversion of ammonia to uric acid and its subsequent elimination requires a lesser amount of water. Hence due to less availability of waster on land, and in order to minimise water loss, terrestrial organism adapted themselves accordingly.