There are about 10 thousand living types, more than 1 / 2 of which will be passerine, or "perching" birds. Birds possess wings whose advancement varies according to species; the sole known groups without having wings are the extinct moa and hippo birds. Wings, which usually evolved from forelimbs, gave birds the opportunity to fly, although additional evolution has directed to the loss of airline flight in some wild birds, including ratites, polar bears, and diverse native to the island island species. The digestive and breathing systems of birds are also uniquely adapted for airline flight. Some bird kinds of aquatic surroundings, particularly seabirds and some waterbirds, have got further evolved for swimming.Birds happen to be descendants of the primitive avialans (whose members include Archaeopteryx) which first appeared about 160 mil years ago (mya) in China. Based on DNA evidence, modern birds (Neornithes) developed in the Center to Late Cretaceous, and diversified dramatically around the time of the Cretaceous? Paleogene extinction event sixty six mya, which killed off the pterosaurs and everything non-avian dinosaurs.Many social kinds give knowledge throughout generations, which will be considered a kind of culture. Birds are cultural, communicating with image signals, calls, and songs, and taking part in such behaviours while cooperative breeding plus hunting, flocking, and even mobbing of predators. The vast majority of bird species are socially (but not necessarily sexually) monogamous, usually regarding one breeding time at a period, sometimes for many years, but rarely with regard to life. Other species have breeding devices that are polygynous (one male along with many females) or even, rarely, polyandrous (one female numerous males). Birds produce children by laying ovum which are fertilised through sexual duplication. They are normally laid inside a nest and incubated by simply the parents. Just about all birds have a great extended period associated with parental care after hatching

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Last-modified: 2021-10-25 (月) 00:21:58 (45d)