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Plant Sciences, Zoology & Evolution / Why Darwin was wrong about the tree of life
« on: 21/03/2009 01:55:03 »I think you've got it wrong about fossils. They are formed under fairly special conditions and not be some zealous zoologist collector. The data is far from complete, as you might expect.
Btw, what data do you have for your theory?
Try and get this Sophie. It's really not too difficult to follow.
Darwin's idea of the incompleteness of the fossil record was complete nonsense. There are so many fossils available today, that argument is a complete non-starter.
"Well, we are now about 120 years after Darwin and the knowledge of the fossil record has been greatly expanded. We now have a quarter of a million fossil species but the situation hasn't changed much. The record of evolution is still surprisingly jerky and, ironically, we have even fewer examples of evolutionary transition than we had in Darwin's time. By this I mean that some of the classic cases of Darwinian change in the fossil record, such as the evolution of the horse in North America, have had to be discarded or modified as a result of more detailed information - what appeared to be a nice simple progression when relatively few data were available now appears to be much more complex and much less gradualistic. So Darwin's problem has not been alleviated in the last 120 years and we still have a record which does show change but one that can hardly be looked upon as the most reasonable consequence of natural selection."
David M. Raup, "Conflicts Between Darwin and Paleontology," Field Museum of Natural History Bulletin, Vol. 50, No. 1, January 1979, p. 25. (He says a similar thing on p. 50.)
http://evolution-facts.org/New-material/Cambrian%20Explosion.pdf
As Darwin himself wrote, before the different phyla appeared there must have been "vast periods" during which "the world swarmed with living creatures" (Excerpt A, p. 83). In the fossil record, however, most of the major animal phyla appear fully formed at the beginning of the geological period known as the Cambrian, with no fossil evidence that they branched off from a common ancestor. Darwin was aware of this, acknowledging in The Origin of Species that "several of the main divisions of the animal kingdom suddenly appear in the lowest known fossiliferous rocks." He called this a "serious" problem which "at present must remain inexplicable; and may be truly urged as a valid argument against the views
here entertained" (Excerpt A, pp. 82, 85).
(A) Charles Darwin, The Origin of Species, Sixth Edition (New York: D,
Appleton, 1890), Chapter X.
What significance does the Cambrian explosion have for evaluating Darwin's theory that all animals are modified descendants of a common ancestor? As we have seen, Darwin himself considered it a serious problem (Excerpt A). Although Darwin's theory predicts that animal evolution should proceed from the "bottom up," with the largest differences emerging last, James Valentine and his colleagues wrote in 1991 that
the pattern of the Cambrian explosion "creates the impression that metazoan evolution has by and large proceeded from the 'top down' " (Excerpt B, p. 294).
Harry Whittington,an expert on the Cambrian fossils from the Burgess shale, wrote in 1985:
"It may well be that metazoan animals arose independently in different areas. I look sceptically upon diagrams that show the branching diversity of animal life through time, and come down at the base to a single kind of animal" (Excerpt F, p. 131).
Evolutionary biologist Jeffrey Levinton, though convinced of the common ancestry of animals, acknowledged in 1992 that the Cambrian explosion -- "life's big bang," as he called it -- remains "evolutionary biology's deepest paradox" (Excerpt G, p. 84). Although "the body plans that evolved in the Cambrian by and large served as the blueprints for those seen today,"
Levinton saw "no reason to think that the rate of evolution was ever slower or faster than it is now. Yet that conclusion still leaves unanswered the paradox posed by the Cambrian explosion and the mysterious persistence of those ancient body plans" (Excerpt G, pp. 84, 90).
In 1999,University of California biologist Malcolm Gordon wrote: "Recent research results make it seem improbable that there could have been single basal forms for many of the highest categories of evolutionary differentiation (kingdoms, phyla, classes)" (Excerpt H, p. 331).
Gordon concluded: "The traditional version of the theory of common descent apparently does not apply to kingdoms [i.e., plants, animals, fungi, bacteria] as presently recognized.
It probably does not apply to many, if not all, phyla, and possibly also not to many classes within the phyla" (Excerpt H, p. 335).
References
(F) Harry B. Whittington, The Burgess Shale (New Haven, CT: Yale
University Press, 1985).
(G) Jeffrey S. Levinton, "The Big Bang of Animal Evolution," Scientific
American 267 (November, 1992): 84-91.
(H) Malcolm S. Gordon, "The Concept of Monophyly: A Speculative Essay,"
Biology and Philosophy 14 (1999): 331-348.
That enough, or do you really need more quotes to establish the point that the idea of a branching tree of life is a complete myth?