Tiny fossils reveal inner secrets, BBC, 13 October 2006, Jonathan Fildes ...
[Graphic: four-celled embryo ~550 million years old, Scientific American]
The exact moment when a 550 million year old cell began to divide has been captured in an exquisite 3-D image. The picture is one of a series taken by researchers examining ancient fossil embryos from Guizhou Province, China. The specimens, described in the journal Science, are the oldest known examples of fossil embryos, and shed light on the early evolution of complex life. Also at: ABC, EurekAlert!, Independent Online, MSNBC, PhysOrg.com, Scientific American, Sydney Morning Herald & The Guardian.
Scientists used an advanced X-ray technique to peer inside the balls of cells to reveal the structures inside ... These fossilised Precambrian embryos themselves are not new (having been first reported in 1998 in both Nature and Science), just the use of more advanced imaging to reveal embryos' individual cells dividing.
Although complex animals had started evolving before 542 million years ago their development accelerated at this point. Although the bed is packed full of the tiny fossils, the team has been unable to find any adult specimens. ... Although the cells show some modern traits they crucially lack others. "Even in these late-stage embryos there is no evidence of the formation of a tissue layer," said Dr Donoghue. "You would expect to see that in modern embryos, even those of sponges." The team believes the cells probably came from extremely simple creatures. "They would have developed into sponge-like creatures, but more primitive," ... If right, this means that the Cambrian Explosion theory for the origin of complex animal life would still stand ... More evidence for the reality of the Cambrian explosion, i.e. all the complex multicellular animal phyla really did arise "in a geological moment":
"The Cambrian Explosion occurred in a geological moment, and we have reason to think that all major anatomical designs may have made their evolutionary appearance at that time." "... not only the phylum Chordata itself, but also all its major divisions, arose within the Cambrian Explosion." "Contrary to Darwin's expectation that new data would reveal gradualistic continuity with slow and steady expansion, all major discoveries of the past century have only heightened the massiveness and geological abruptness of this formative event for the kingdom Animalia." (Gould, S.J., "Of it, not above it," Nature, Vol. 377, 26 Oct 1995, pp.681-682. Emphasis original).
And another nail in the coffin of the Darwinian artifact theory," i.e. "Precambrian [complex invertebrate] ancestors" to the Cambrian animal phyla "did exist, but the fossil record hasn't preserved them"; and more evidence for "the fast-transition theory", i.e. "they really didn't exist, at least as complex invertebrates easily linked to their descendants, and the evolution of modern anatomical plans occurred with a rapidity that threatens our usual ideas about the stately" (i.e. Darwinian) "pace of evolutionary change":
"Two different kinds of explanations for the absence of Precambrian ancestors have been debated for more than a century: the artifact theory (they did exist, but the fossil record hasn't preserved them), and the fast-transition theory (they really didn't exist, at least as complex invertebrates easily linked to their descendants, and the evolution of modern anatomical plans occurred with a rapidity that threatens our usual ideas about the stately pace of evolutionary change). ... We can now understand why Walcott was virtually compelled to propose the Burgess shoehorn. He interpreted his new fauna in the light of thirty previous years spent (largely in frustration) trying to prove the artifact theory, as an ultimate tribute to Darwin from a Cambrian geologist. He could not grant Burgess organisms the uniqueness that seems so evident to us today because a raft of new phyla would have threatened his most cherished belief. If evolution could produce ten new Cambrian phyla and then wipe them out just as quickly, then what about the surviving Cambrian groups? Why should they have had a long and honorable Precambrian pedigree? Why should they not have originated just before the Cambrian, as the fossil record, read literally, seems to indicate, and as the fast- transition theory proposes? This argument, of course, is a death knell for the artifact theory." (Gould, S.J., "Wonderful Life: The Burgess Shale and the Nature of History," , Penguin: London, 1991, reprint, pp.270-273).
But as Phillip E. Johnson comments on the above quote by Gould, "A mysterious process that produces dozens of complex animal groups directly from single-celled predecessors, with only some words like `fast- transition' in between, may be called `evolution'-but ... Each of those Cambrian animals contained a variety of immensely complicated organ systems. How can such innovations appear except by the gradual accumulation of micromutations, unless there was some supernatural intervention? ... If he really rejects the artifact theory of the Precambrian fossil record, Gould also rejects the Darwinian theory of evolution." (my emphasis):
"Darwinism's rules of reasoning not only protect the cultural authority of Darwinists. They also permit Darwinist writers to take the mutation/selection paradigm for granted even when they are describing evidence that directly contradicts it. This feat of intellectual contortionism is strikingly illustrated by Stephen Jay Gould's book, Wonderful Life. Gould's best seller adds a great deal to our knowledge of the `Cambrian explosion,' meaning the sudden appearance of the invertebrate animal phyla, without visible ancestors, in the 600 million-year-old rocks of the Cambrian era. Unicellular life had existed for a long time, and some multicellular groups appear in the immediately Precamhrian rocks, hut nothing can be established as ancestral to the Cambrian animals. As Richard Dawkins described the situation, `It is as though the Cambrian phyla] were just planted there, without any evolutionary history.' [Dawkins, R., "The Blind Watchmaker," Longman, 1986, p.229] In recent years the mystery has deepened, because it appears that the Cambrian animal groups were far more varied than had been imagined. The more distinct groups that there were in the Cambrian, the more chains of ancestors there ought to have been in the Precambrian Some remarkable Cambrian fossils found in a Canadian formation known as the Burgess Shale were originally classified in familiar groups. Gould explains that the discoverer of the Burgess Shale fossils, Charles Walcott, tried to `shoehorn' the odd creatures into familiar taxonomic categories because of his predisposition to avoid multiplying the difficulties of what is called the `artifact theory' of the Precambrian fossil record. As Gould explains the problem: ... A mysterious process that produces dozens of complex animal groups directly from single-celled predecessors, with only some words like `fast- transition' in between, may be called `evolution'-but the term is being used more in the sense of Grassé's heresy than of Dobzhansky's Darwinian orthodoxy. Each of those Cambrian animals contained a variety of immensely complicated organ systems. How can such innovations appear except by the gradual accumulation of micromutations, unless there was some supernatural intervention? It is not only that the Darwinian theory requires a very gradual line of descent from each Cambrian animal group back to its hypothetical single-celled ancestor. Because Darwinian evolution is a purposeless, chance-driven process, which would not proceed directly from a starting point to a destination, there should also be thick bushes of side branches in each line. As Darwin himself put it, if Darwinism is true the Precambrian world must have `swarmed with living creatures' [Darwin, C.R., "The Origin of Species," 1872, Sixth Edition, Senate: London, 1994, p.286] many of which were ancestral to the Cambrian animals. If he really rejects the artifact theory of the Precambrian fossil record, Gould also rejects the Darwinian theory of evolution." (Johnson, P.E., "Darwinism's Rules of Reasoning," in Buell, J. & Hearn, V., eds., "Darwinism: Science or Philosophy?," Foundation for Thought and Ethics: Richardson TX, 1994, pp.12-14).
Stephen E. Jones, BSc (Biol).
Genesis 6:5-7. 5The LORD saw how great man's wickedness on the earth had become, and that every inclination of the thoughts of his heart was only evil all the time. 6The LORD was grieved that he had made man on the earth, and his heart was filled with pain. 7So the LORD said, "I will wipe mankind, whom I have created, from the face of the earth-men and animals, and creatures that move along the ground, and birds of the air-for I am grieved that I have made them."
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