With regards to toxicity and the need for dilution in water, how different are ureotelic and uricotelic excretions? Give examples of animals that use these types of excretion. Ureotelism:
1. The process of excreting urea is called ureotelism.
2.Animals which are found in places where water availability is not abundant have this mode of excretion.
3. They convert Ammonia produced in the body into urea in the liver and release it to the blood. This is filtered and excreted by the kidneys, Eg: Mammals, many terrestrial amphibians and marine fishes.
4.In terms of toxicity urea is more toxic than uric acid but it is soluble in water and is thus excreted as urine.

Explanation

Uricotelism :
1. The process of excreting uric acid is called uricotelism.
2. Uric acid can be removed from the body with a minimal loss of water and the excreta is in the form of pellet or paste (semisolid).
3. Eg. : Many desert animals, Reptiles, Birds, Insects.
4. In terms of toxicity, uric acid is the least toxic nitrogenous waste. It is also insoluble in water.