Animalia Life

Type of animal science: Classification
Fields of study: Anatomy, evolutionary science, ornithology, physiology, systematics (taxonomy), zoology
There are about 8,600 hundred living species of birds, in about twenty-eight taxonomical orders. All birds have feathers, a feature unique to them; most birds also have other evolutionary adaptations that enable them to fly.



Within the animal kingdom is a class of animals that has 8,600 living species, with each species having a feature found in no other class of animals: feathers. These animals, the birds, also have horny beaks, two hind limbs that allow them to walk, swim, or perch, and two forelimbs called wings, which often help them to fly or swim. Birds have anatomical systems that are quite similar to those of mammals, and both of these classes of animals are warm-blooded, or endothermic. Along with other vertebrates, birds have skeletal, muscular, circulatory, digestive, respiratory, urinary, reproductive, and nervous systems. They have an outer covering of skin and a variety of sense organs. Each system, however, has unique adaptations designed to enable birds to fly.

Bird Facts

Archaeopteryx: the earliest known bird, known only from the fossil record; it lived during the Jurassic period
Aves: the class within the phylum Chordata to which all birds, and only birds, belong
Crop: a specialized part of a bird’s digestive system that holds and softens food Endotherm: an animal that, by its own metabolism, maintains a constant body temperature (is “warm-blooded”); birds and mammals are endotherms
Gizzard: a part of a bird’s stomach that uses ingested pebbles to grind up food
Ornithology: the branch of biology that deals with the study of birds
Thecodonts: extinct reptiles that lived during the Permian period; they were the ancestors of both dinosaurs and birds

Other popular Animals