Class Aves - An Introduction
Birds (Class Aves) are feathered, winged, two legged vertebrates. They are generally characterised by feathers, a beak, wings, and the laying of hard-shelled eggs. Birds are the most recently evolved of the vertebrate classes, with the oldest fossils going back about 160 million years. They are considered to be the modern descendants of the dinosaurs since they are the only direct evolutionary line that survived the extinction event which wiped out the dinosaurs about 65 million years ago. Class Aves is part of the subphylum Vertebrata, which is a part of the phylum Chordata and then the kingdom Animalia.
A Comparison Between Orders
Read about the comparison of the orders Strigiformes and Accipitriformes through the link below!