Classification of vertebrates.

Classification of vertebrates.

1. Vertebrates can be subdivided into five major groups...

   • FISHES
     • Fishes are non-tetrapod vertebrates, they generally have two pairs of fins and several unpaired fins that allow them to move efficiently through water. they are almost all entirely aquatic. their habitats cover all aquatic regions on earth
   • AMPHIBIANS
     • Amphibians are cold-blooded vertebrate tetrapods that generally respire air as adults but usually require an aquatic environment for reproduction. Almost all amphibian species produce eggs that cannot survive outside of water, and this is the reason for their reproductive dependence on an aquatic environment
   • REPTILES
     • Reptiles are also cold-blooded vertebrate tetrapods, reptiles are amniotes that are not dependent on water in order to reproduce. Amniotes lay eggs that are surrounded by an extensive amniotic membrane to facilitate gas exchange and waste processing in a terrestrial environment. A solid eggshell surrounds the membrane-enclosed embryos and provides protection to the developing organism. All reptiles use lungs to breath, although there are some species that are also able to absorb oxygen through their skin.
   • BIRDS
     • Birds are warm-blooded (endothermic), egg-laying vertebrate tetrapods. They are characterized by the presence of feathers and wings. Almost all birds are capable of flight.
   • MAMMALS
     • Mammals are warm-blooded vertebrates that differ in many ways from members of other vertebrate classes. Mammals have hair on their skin, three bones in the middle ear, a four-chambered heart, and a region of the brain called a neocortex