Descripción: Natural History Museum of Los Angeles County.
«Birds belong to the Class Aves in the Kingdom Animalia. Birds are the only animals that have feathers and all birds have feathers. Other characteristics of modern birds include: forelimbs modified into wings, no teeth, scales on the feet, a four chambered heart, egg-laying, clavicles (collar bones) united as furculum (or wishbone) and warm-bloodedness.
Scientists have divided the Class Aves into around 25 to 30 orders. Each order is subdivided into families of related genera and species (kinds). Scientists group birds together by searching for common structural characteristics of their anatomy and similarities in the genetic material.»
