Water loss during excretion

In terrestrial animals body water is also lost during excretion of nitrogenous wastes. A number of physiological adaptations have taken place to minimise the loss of water associated with this phenomena. You have learnt in the previous Unit that among terrestrial invertebrates, insects are highly effective in conserving water.

In terrestrial vertebrates, kidney is the chief organ of osmoregulation and excretion. The loop of Henle is the specialised part of the nephron which produces hyperosmotic urine. Amphibians and reptiles which are unable to produce a hyperosmotic urine, as an adaptive consequence, cease urine production entirely during the period of osmotic stress.