Types of Animals Based on Excretory Wastes - Practice Questions & MCQ

Ammonotelism:

• The process of excreting ammonia is Ammonotelism.
• Many bony fishes, aquatic amphibians and aquatic insects are ammonotelic in nature.
• Ammonia, as it is readily soluble, is generally excreted by diffusion across body surfaces or through gill surfaces (in fish) as ammonium ions. 
• Kidneys do not play any significant role in its removal.

Ureotelism:

• Terrestrial adaptation necessitated the production of lesser toxic nitrogenous wastes like urea and uric acid for the conservation of water
• Mammals, many terrestrial amphibians and marine fishes 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 by the kidneys. 
• Some amount of urea may be retained in the kidney matrix of some of these animals to maintain the desired osmolarity.

Uricotelism:

• Reptiles, birds, land snails and insects excrete nitrogenous wastes as uric acid in the form of a pellet or paste with a minimum loss of water and are called uricotelic animals.