The are a lateral line, that sense vibrations in the water, and they lack an active system for pumping water across their gills. The bony fishes have skeleton made of bone. Bony fishes have a gas filled swim bladder that they use to control bouyancy. Typically terrestrial as adults with reproduction occuring in freshwater. Amphibians were thee earliest tetrapods.
Skin is covered with scales composed of protein called keratin.
There is no larval stage. They have amniotic eggs. Current thinking holds that birds evolved for an ancestral bi-pedal dinosaur. Mammals are a largely terrestrial group with hair and milk producing glands. They are endotherms.