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Synonyms. Neornithes Gadow, 1883. Birds are a group of warm-blooded vertebrates constituting the class Aves ( / ˈeɪviːz / ), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton.
Ostriches. This article lists living orders and families of birds. The links below should then lead to family accounts and hence to individual species. The passerines (perching birds) alone account for well over 5,000 species.
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What type of animal is a bird?
Where did birds originate?
Are birds a phylogeny?
Which clade is a bird in?
The scientific question of within which larger group of animals birds evolved has traditionally been called the "origin of birds". The present scientific consensus is that birds are a group of maniraptoran theropod dinosaurs that originated during the Mesozoic Era.
Birds are bipedal, warm-blooded, egg-laying vertebrates characterized primarily by feathers, forelimbs modified as wings, and hollow bones. This category contains taxa at the order or higher level in the class of Aves. For individual species of birds, see the and .
The Birds Portal. Birds are a group of warm-blooded vertebrates constituting the class Aves ( / ˈeɪviːz / ), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton.
Bird anatomy, or the physiological structure of birds' bodies, shows many unique adaptations, mostly aiding flight. Birds have a light skeletal system and light but powerful musculature which, along with circulatory and respiratory systems capable of very high
The evolution of birds began in the Jurassic Period, with the earliest birds derived from a clade of theropod dinosaurs named Paraves. Birds are categorized as a biological class, Aves. For more than a century, the small theropod dinosaur from the Late Jurassic
