One of the most extensive animal radiations is that of terrestrial arthropods (including insects). They excrete uric acid as their form of nitrogenous waste. Why does excreting uric acid allow them to conserve more water than a mammal that has extensive kidney tubules for water reabsorption?

Question

Quizplus · Accepted Answer

Uric acid is relatively insoluble in water and precipitates out of solution, which means it does not exert osmotic pressure that would otherwise pull water back into the excretory system. This allows terrestrial arthropods to conserve water by excreting a semi-solid paste or pellet, minimizing water loss in their waste.

One of the Most Extensive Animal Radiations Is That of Terrestrial