chordates

• class Agnatha - Jawless
• Class chondricthyes - Jawed fish, cartilaginous fish
• class osteichthyes - protrusible jaws, bony fish
• class amphibia - tetrapods, they are ectothermic
• class reptilia - amniotes
• class aves - flying vertebrates, they are endothermic
• class mammalia - gives birth to live young; characterised by the presence of milk-producing mammary glands for feeding their young