Origin of avian flapping flight

抄録

  The idea that birds’ ancestors are bipedal theropod dinosaurs is now accepted. But there have been various theories about the origin of avian flapping flight for more than a century, and there is still no theory that convinces everyone. The basis of the conventional theories is critically examined here, and a new rationale is presented. Therefore, the method of vertebrate paleobiology for the purpose of restoration and elucidation of evolution is used. Actually, the most plausible hypothesis was already presented long ago, and the evidence of fossils needed to support it has been found. There has been no reasonable basis to maintain otherwise. Animal locomotion is the movement of the center of gravity of the body. The center of gravity of the body is on the legs of bipedal dinosaurs and at the base of the wings that produce lift in flying animals. In the evolution from dinosaurs to birds, the center of gravity of the body must shift from the pelvis to the chest. In conclusion, the tetrapteryx theory of Beebe makes the most sense, and now Anchiornis from the Jurassic of Liaoning Province, China is the most informative fossil.