| 词条 | Forelimb |
| 释义 |
A forelimb is an anterior limb (arm, leg, or similar appendage) on a terrestrial vertebrate's body. With reference to quadrupeds, the term foreleg is often used instead. (A forearm, however, is the part of the human arm or forelimb between the elbow and the wrist.) All vertebrate forelimbs are homologous, meaning that they all evolved from the same structures. For example, the flipper of a turtle or of a dolphin, the arm of a human, the foreleg of a horse, and the wings of both bats and birds{{efn|Bat wings are however composed largely of a thin membrane of skin supported on the five fingers, whereas bird wings are composed largely of feathers supported on much reduced fingers, with finger 2 supporting the alula and finger 4 the primary feathers of the wing; there are only distant homologies between birds and bats, with much closer homologies between any pair of bird species, or any pair of bat species.}} are ultimately analogous, despite the large differences between them.[1] Bibliography
Notes{{notelist}}References1. ^{{cite web | url= http://www.britannica.com/EBchecked/media/45466/Homologies-of-the-forelimb-among-vertebrates-giving-evidence-for-evolution | title= Image Gallery: Homo Sapiens. homology: homologies of the forelimb among vertebrates | publisher= Encyclopædia Britannica | accessdate= January 27, 2013}} {{vertebrate anatomy-stub}} 2 : Limbs (anatomy)|Vertebrate anatomy |
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