Class Aves (Reptilia) (Phylum Chordata)
Examples and Traits
Class Aves is the birds, with about 8600 species. Originally it's own class, it is now part of Class Reptilia. The Avian reptiles have amniotic eggs with brittle shells. They are endothermic. They have very lightweight but strong bones, and have feathers made with keratin. They have a large sternum to provide the power necessary to fly. They have well developed lungs with air sacs, and a four chambered heart. Their crop and gizzard make up the "stomach". Their kidneys produce uric acid for excretion. They have a cloaca. Their vision is great, along with their auditory sense, but they have a poor sense of smell.