Birds
https://www.pinterest.com/pin/649644315004712474/
There are about ten thousand living varieties, more than half of which happen to be passerine, or "perching" birds. Birds have wings whose growth varies according in order to species; the sole known groups without having wings will be the vanished moa and elephant birds. Wings, which in turn evolved from forelimbs, gave birds the opportunity to fly, although further evolution has brought to loosing air travel in some chickens, including ratites, penguins, and diverse endemic island species. The digestive and breathing systems of birds are also distinctly adapted for flight. Some bird species of aquatic environments, particularly seabirds in addition to some waterbirds, include further evolved for swimming.
Birds happen to be descendants of the primitive avialans (whose members include Archaeopteryx) which first came out about 160 mil years ago (mya) in China. Based on DNA evidence, contemporary birds (Neornithes) advanced in the Midsection to Late Cretaceous, and diversified significantly around the time of the Cretaceous? Paleogene extinction event 66 mya, which slain off the pterosaurs and non-avian dinosaurs.
Many social kinds give knowledge across generations, which is usually considered a kind of tradition. Birds are social, communicating with image signals, calls, plus songs, and participating in such behaviours as cooperative breeding and hunting, flocking, and even mobbing of predators. The vast bulk of bird kinds are socially (but not necessarily sexually) monogamous, usually with regard to one breeding season at a time, sometimes for years, but rarely intended for life. Other varieties have breeding techniques that are polygynous (one male together with many females) or perhaps, rarely, polyandrous (one female numerous males). Birds produce offspring by laying ovum which are fertilised through sexual processing. They are usually laid within a call home and incubated by simply the parents. Many birds have the extended period of parental care right after hatching
