Bird

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Pictured: A male specimen (left) and a female specimen (right) from a reasonably tasty species of bird (Gallus gallus domesticus).

Birds are a warm-blooded class of vertebrate animals, with beaks, wings and feathers, known for flying through the air and also sometimes being delicious.

Like mammals, another warm-blooded group, birds evolved from reptiles, most likely small coeleosaurs, diverging during the Jurassic period. Birds are bipeds, walking on two legs, and are descended from theropods[1], a bipedal group of dinosaurs, the front limbs having gradually evolved into wings. Archaeopteryx is a famous proto-bird, because it was one of the first feathered dinosaurs discovered; however, modern taxonomists believe that Archaeopteryx was closer to dinosaurs than birds, and is only a relative of the common ancestor of dinosaurs and birds rather than an example of it.

All birds have wings, and most use them for flight, though there are many flightless species, including penguins, which use their wings for swimming instead. Other flightless birds such as the emu and the kiwi have no use for wings at all, but still have them, no matter how small and stubby. In addition, domesticated birds tend to lack their wild cousins' flying abilities as a result of artificial selection and tend to taste better (though not necessarily because of the lack of flight; that's also a result of artificial selection). Contrast, for example, the strong flying abilities of the quick (they're pretty good at running as well) Wild Turkey with the lack of flying ability of their slow and fat domesticated counterparts.

Respectable scientist Thomas Huxley proposed the bird–dinosaur link way back in 1868. This correct line of thought was derailed in 1926 with the publication of The Origin of Birds by Gerhard Heilmann. Exhaustively researched, it wanted to conclude that birds were dinosaurs, but was hung up on the fact that birds have clavicles, but dinosaurs apparently did not. The explanation, obvious in retrospect, is that collarbones are thin and don't fossilize as often as bigger bones. Nonetheless, the book was so dazzling that no one questioned it very hard for the next 40 years, even though the discovery of dinosaur clavicles was already underway at the time of its publication.[2][3]

A 2014 study of the DNA of living and recently extinct flightless birds found that flightlessness evolved independently on different landmasses, an example of convergent evolution.[4] A second 2014 study of bird DNA across all major groups of birds confirmed that birds evolved rapidly following the extinction of other dinosaurs.[5]

It should be known that the bird → the word.

[edit] See also

  • Goats, which aren't birds, but are nevertheless worth mentioning.
  • Insects, which include species that birds eat.
  • Mammals, which include species that eat birds, including us (except for vegetarians) and furry animals that live among us. Large birds often eat smaller mammals.
  • Feathered dinosaurs
  • Reptiles, which look more like dinosaurs than birds do and don't taste as good.
  • Cock, the males of the species pictured above.
  • Xenicibis a particularly bad-ass specimen.

[edit] Footnotes

  1. Or a very closely-related group - every year, new evidence refines the phylogenetic tree.
  2. Origin of birds#Heilmann and the thecodont hypothesis
  3. The Origin of Birds#Legacy
  4. Flightless birds’ history upset by ancient DNA
  5. Flock of geneticists redraws bird family tree: Birds get fresh perches in revamped tree of life built by vast collaboration
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