Question

give a comparative account of 5 class of phylum vertebrata based on :
(1) organs for breathing
(2) chambers in heart.

Answer 1

First of all there is some mistake in the question. Vertebrata is not the phylum. Phylum is chordata. Under this phylum, comes two sub-phylums: hemichordata and vertebrata. Now there are five classes under phylum chordata and they are also vertebrates. These are: (a) Pisces:  They breathe through gills and have two chambered heart. (b) Amphibians: They breathe through gills in larval stage and later on in adult stage, they respire through lungs and skin. They have three chambered heart. (c) Reptiles: They breathe through lungs and have three chambered heart. Crocodiles are exceptional as they have incompletely developed or half developed four chambered heart, therefore sometimes they are known to have 3.5 chamber heart. (d) Aves: They respire through lungs with which air sacs are attached as a mode of flight modification and they have fully developed four chambered heart. (e) Mammals: They respire through lungs and have four chambered heart.