There has been an increase in the number of chambers in heart during evolution of vertebrates. Give the names of the class of vertebrates having two, three or four-chambered heart.

Vertebrates having –

Two-chambered hearts: Chrondrichytes and osteichytes

Three- chambered heart: Amphibia and Reptile

Four-chambered heart: Aves and mammalian

In two-chambered heart, there is one atria and one ventricle present which are not separated due to which oxygenated and deoxygenated blood mixes.

Three-chambered heart is developed due to the division of auricle into right and left halves.

In four chambered heart, both the auricle and ventricle are divided into two halves and thus no mixing of oxygenated and deoxygenated blood.