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drj11 -> RE: ?empirical evidence? (4/5/2008 12:51:01 PM)
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quote:
ORIGINAL: Bettawrekonize
Look at the link that unclemonkey gave you, read it. Trueorigins refutes some talkorigins sites.
From your URL
quote:
A vestige is defined, independently of evolutionary theory, as a reduced and rudimentary structure compared to the same complex structure in other organisms.
http://www.talkorigins.org/faqs/comdesc/section2.html#morphological_vestiges
This is not how darwin defined it. More evidence of goal posts being moved. They find out that many of the alleged vestigial organs were more useful than Darwin predicted so instead of admitting that UCD is wrong, they simply re - define the word.
I don't see how two organisms having "similar" structures and one having a different or "lessor" function than another is evidence that they share a common ancestor. Perhaps the different structures were designed for different purposes and on one organism it wasn't designed to do as much since it's not as necessary for it. The notion that they got the structures from a common ancestor merely assumes that they share a common ancestor, the structures themselves are not evidence of a common ancestor.
From the link I gave you:
quote:
Darwin in fact emphasizes that vestiges can be functional and gives several examples:
"Useful organs, however little they may be developed, unless we have reason to suppose that they were formerly more highly developed, ought not to be considered as rudimentary." (Darwin 1859, emphasis added)
"An organ, serving for two purposes, may become rudimentary or utterly aborted for one, even the more important purpose, and remain perfectly efficient for the other. Thus, in plants, the office of the pistil is to allow the pollen-tubes to reach the ovules protected in the ovarium at its base. The pistil consists of a stigma supported on the style; but in some Compositae, the male florets, which of course cannot be fecundated, have a pistil, which is in a rudimentary state, for it is not crowned with a stigma; but the style remains well developed, and is clothed with hairs as in other compositae, for the purpose of brushing the pollen out of the surrounding anthers. Again, an organ may become rudimentary for its proper purpose, and be used for a distinct object: in certain fish the swim-bladder seems to be rudimentary for its proper function of giving buoyancy, but has become converted into a nascent breathing organ or lung. Other similar instances could be given." (Darwin 1859 [see text]; also Darwin 1872, p. 602, emphasis added)
"Rudimentary organs, on the other hand, are either quite useless, such as teeth which never cut through the gums, or almost useless, such as the wings of an ostrich, which serve merely as sails." (Darwin 1872, p. 603)
"... an organ rendered, during changed habits of life, useless or injurious for one purpose, might easily be modified and used for another purpose." (Darwin 1872, p. 603)
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