Dictionary Meaning and Definition on 'Aves'
n : birds [syn: class Aves]
- Aves \A"ves\, n. pl. [L., pl. of avis bird.] (Zo["o]l.)
The class of Vertebrata that includes the birds.
Note: Aves, or birds, have a complete double circulation,
oviparous, reproduction, front limbs peculiarly
modified as wings; and they bear feathers. All existing
birds have a horny beak, without teeth; but some
Mesozoic fossil birds (Odontornithes) had conical teeth
inserted in both jaws. The principal groups are:
Carinat[ae], including all existing flying birds;
Ratit[ae], including the ostrich and allies, the
apteryx, and the extinct moas; Odontornithes, or
fossil birds with teeth.
Note: The ordinary birds are classified largely by the
structure of the beak and feet, which are in direct
relation to their habits. See Beak, Bird,
Wikipedia Meaning and Definition on 'Aves'
Birds (class Aves) are feathered, winged, bipedal, endothermic (warm-blooded), egg-laying, vertebrate animals. There are around 10,000 living species, making them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from the 5 cm (2 in) Bee Hummingbird to the 2.75 m (9 ft) Ostrich. The fossil record indicates that birds evolved from theropod dinosaurs during the Jurassic period, around 150–200 Ma (million years ago), and the earliest known bird is the Late Jurassic Archaeopteryx, c 150–145 Ma. Most paleontologists regard birds as the only clade of dinosaurs to have survived the Cretaceous–Tertiary extinction event approximately 65.5 Ma.
Modern birds are characterised by feathers, a beak with no teeth, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. All living species of birds have wings - the now extinct flightless Moa of New Zealand were the only exceptions. Wings are evolved forelimbs, and most bird species can fly, with some exceptions including ratites, penguins, and a number of diverse endemic island species. Birds also have unique digestive and respiratory systems that are highly adapted for flight. Some birds, especially corvids and parrots, are among the most intelligent animal species; a number of bird species have been observed manufacturing and using tools, and many social species exhibit cultural transmission of knowledge across generations.[See more about Aves at Dictionary 3.0 Encyclopedia]