Bird

A Bird is a living organism that is descended from a theropod dinosaurs (during the Jurassic period).

• Context:
  • It can range from being a Flying Bird to being a Swimming Bird to being a Walking Bird.
  • …
• Example(s):
  • a Chicken.
  • a Duck.
  • a Penguin.
  • a Dodo Bird.
  • an Enantiornithine Bird, that went extinct in the Cretaceous-Paleogene boundary (but whose feathers have been found in amber[1]).
  • Telluraves, such as Owls.
  • …
  • a Hesperones (still has teeth).
  • a Confusiorness.
  • an Archaeopteryx.
  • …
• Counter-Example(s):
  • a Non-Avian Dinosaur.
  • a Mammal.
• See: Class (Biology), Feather, Bird Flight, Bipedalism, Warm-Blooded, Egg (Biology), Vertebrate, Extant Taxon, Modern Birds.

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References

2014

• (Wikipedia, 2014) ⇒ http://en.wikipedia.org/wiki/Bird Retrieved:2014-9-27.
  • Birds (class Aves or clade Avialae) are feathered, winged, two-legged, warm-blooded, egg-laying vertebrates. Aves ranks as the tetrapod class with the most living species, approximately ten thousand. Extant birds belong to the subclass Neornithes, living worldwide and ranging in size from the bee hummingbird to the ostrich. The fossil record indicates that birds emerged within the theropod dinosaurs during the Jurassic period, around On 31 July 2014, scientists reported details of the evolution of birds from theropod dinosaurs. Most researchers agree that modern-day birds are the only living members of the Dinosauria clade.

     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. Extant birds have wings; the most recent species without wings was the moa, which is generally considered to have become extinct in the 16th century. Wings are evolved forelimbs, and most bird species can fly. Flightless birds include ratites, penguins, and diverse endemic island species. Some species of birds, particularly penguins and members of the Anatidae family, are adapted to swim. Birds also have digestive and respiratory systems that are uniquely adapted for flight. Some birds, especially corvids and parrots, are among the most intelligent animal species; several bird species make and use tools, and many social species culturally transmit knowledge across generations.

    Many species annually migrate great distances, and many more perform shorter irregular movements. Birds are social, communicating with visual signals, calls, and songs, and participating in such social behaviours as cooperative breeding and hunting, flocking, and mobbing of predators. The vast majority of bird species are socially monogamous, usually for one breeding season at a time, sometimes for years, but rarely for life. Other species have polygynous ("many females") or, rarely, polyandrous ("many males") breeding systems. Eggs are usually laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching.

    Many species are economically important, mostly as game or poultry. Some species, particularly songbirds and parrots, are popular as pets. Another use of birds is harvesting guano (droppings) for use as a fertiliser. Birds prominently figure throughout human culture. About 120–130 species have become extinct due to human activity since the 17th century, and hundreds more before then. Human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them.

• http://en.wikipedia.org/wiki/Theropoda
  • QUOTE: … Theropods first appeared during the Carnian age of the late Triassic period about 230 million years ago (Ma) and included the sole large terrestrial carnivores from the Early Jurassic until at least the close of the Cretaceous, about 66 Ma. In the Jurassic, birds evolved from small specialized coelurosaurian theropods, and are today represented by 10,000 living species.
    On July 31, 2014, scientists reported details of the evolution of birds from theropod dinosaurs. Among the features linking theropod dinosaurs to birds are a furcula (wishbone), air-filled bones, brooding of the eggs, and (in coelurosaurs, at least) feathers.

• (Brusatte et al., 2014) ⇒ Stephen L. Brusatte, Graeme T. Lloyd, Steve C. Wang, and Mark A. Norell. (2014). “Gradual Assembly of Avian Body Plan Culminated in Rapid Rates of Evolution across the Dinosaur-Bird Transition.” In: Current Biology, … doi:10.1016/j.cub.2014.08.034
  • Highlights
    • A new phylogeny of birds and their closest dinosaur relatives is presented
    • Birds evolved anatomical features faster than other theropods.
    • Birds are indistinguishable from their closest relatives in morphospace
    • The assembly of the avian body plan unlocked great evolutionary potential
  • Summary
    • The evolution of birds from theropod dinosaurs was one of the great evolutionary transitions in the history of life [1–22]. The macroevolutionary tempo and mode of this transition is poorly studied, which is surprising because it may offer key insight into major questions in evolutionary biology, particularly whether the origins of evolutionary novelties or new ecological opportunities are associated with unusually elevated “bursts” of evolution [23, 24]. We present a comprehensive phylogeny placing birds within the context of theropod evolution and quantify rates of morphological evolution and changes in overall morphological disparity across the dinosaur-bird transition. Birds evolved significantly faster than other theropods, but they are indistinguishable from their closest relatives in morphospace. Our results demonstrate that the rise of birds was a complex process: birds are a continuum of millions of years of theropod evolution, and there was no great jump between nonbirds and birds in morphospace, but once the avian body plan was gradually assembled, birds experienced an early burst of rapid anatomical evolution. This suggests that high rates of morphological evolution after the development of a novel body plan may be a common feature of macroevolution, as first hypothesized by G.G. Simpson more than 60 years ago [25].

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