CBSE Class 7 Answered

Hi Ananya,

The different modes of excretion in animals are as follows:

Ammonotelism

• Excretion of ammonia is called ammonotelism.
• Animals excreting ammonia as a major excretory product are called ammonotelic animals.
• Protozoans, sponges, jelly fish, crustaceans, aquatic insects, bony fish and aquatic amphibians are ammonotelic animals.

Ureotelism

• Excretion of urea is called ureotelism.
• Animals excreting urea as the major nitrogenous waste are called ureotelic animals.
• Frogs, toads, mammals, cartilaginous fish, turtle, aquatic reptiles and mammals are ureotelic animals.

Uricotelism         

• Excretion of uric acid as a nitrogenous waste is called uricotelism.
• Animals excreting uric acid as the major nitrogenous waste are called uricotelic animals.
• Birds, land reptiles, insects, land snails and some land crustaceans are uricotelic animals.

Aminotelism

• Amino acids are excreted without any metabolism.
• All echinoderms and certain molluscs are aminotelic animals.

Guanotelism

• Guanine is the main nitrogenous waste.
• Spiders, scorpions, lizards and certain birds such as gannets, cormorants and pelicans are guanotelic