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Pastimes : Let's Talk About Our Feelings!!! -- Ignore unavailable to you. Want to Upgrade?

To: Tom C who wrote (97861)	3/13/2005 5:05:15 PM
From: Brumar89	Respond to of 108807

Re. the question about Margulis' theory, I'm not as well equipped to answer it as she is, so I would refer you to her book published in 2002: A challenger of the orthodox "neo-Darwinist" interpretation of evolution, microbiologist Margulis has made her professional mark touting an alternative: symbiogenesis. She and coauthor (and son) Sagan have presented their ideas in earlier popular works (What Is Life?, 1995), but never as vigorously as in this volume. Essentially, the debate between neo-Darwinists and Margulis hinges on the definition of a species, and the manner in which a new one appears. To Margulis and Sagan, the neo-Darwinist model, which asserts random gene mutation as the source of inherited variations, is "wildly overemphasized," and to support their view, they delve deeply into the world of microbes. They detail the anatomy of cells with and without nuclei, positing a process of genome ingestion that creates a new species. Surprisingly, the upshot of Margulis' theories is the rehabilitation of Jean Baptiste de Lamarck, whose theory that supposedly acquired traits are hereditary has been ridiculed for 150 years. Polemical and provocative, Margulis and Sagan's work should set many to thinking that evolution has not yet been completely figured out. ...... From one of the great iconoclasts of modern biology, an original, accessible work that sets out, for lay and scientific readers alike, a new theory of how species begin. In this groundbreaking book, Lynn Margulis and Dorion Sagan present an answer to one of the enduring mysteries of evolution--the source of inherited variation that gives rise to new species. Random genetic mutation, long believed to be the main source of variation, is only a marginal factor. As the authors demonstrate in this book, the more important source of speciation, by far, is the acquisition of new genomes by symbiotic merger. The result of thirty years of delving into a vast, mostly arcane literature, this is the first book to go beyond--and reveal the severe limitations of--the "Modern Synthesis" that has dominated evolutionary biology for almost three generations. Lynn Margulis, whom E. O. Wilson called "one of the most successful synthetic thinkers in modern biology," and her co-author Dorion Sagan have written a comprehensive and scientifically supported presentation of a theory that directly challenges the assumptions we hold about the variety of the living world. bookfinder.us remember this theory from Biology 101. If it’s true how does this conflict with Evolutionary Theory? I don’t see a conflict here. What in Evolution would preclude this theory? ..... First, I don’t remember Evolutionary Theory making any predictions on how life came about. Second if Crick’s theory conflicts with evolution theory how did the seeded microorganisms turn into the various species we see on earth today. My theory would be natural selection and chance mutation. Darwin’s theory was called the Origin of Species, not the Origin of Life on Earth! You make a very good point. Darwin never dealt with the origin of life. However, most proponents of evolution do think evolution explains the origin of life and species, I believe. Certainly proponents of evolution like Richard Dawkins mingle "origin of life" arguments into their evolutionary arguments. About whether it's science: I think it clearly meets 1 & 2 on you list - observations and hypothesis. You may be right that it hasn't met 3 or 4. But has natural selection met these? How would you design experiments to test either natural selection or intelligent design? I recall that Darwin said that change was slow and gradual. When fossil evidence of the Cambrian explosion came about, Gould (and others) came up with the theory of punctuated evolution to explain the relatively sudden appearance of a vast number of species. Now it seems to me that theory starts from an observation - the sudden appearance of vast numbers of species - and attempts to explain it. Is that different from what intelligent design theory is doing with the observation of design too complex to have arisen via natural selection? I've done some browsing in books critical of ID. In particular Kenneth Miller's Finding Darwin's God. Darwin takes on some of Behe's arguments from Darwin's Black Box and I was not impressed with the result. He seems to be over-eager in his argumentation. For example, regarding the baterial flagellar motor, he says one of the proteins (I've forgotten the name - think it was initialed TTTP) was a subset of a protein used by some parasitical bacteria to cut a hole in the membranes of other cells. He then writes as if this explains the bacterial motor. Of course, it doesn't. There are 49 other proteins involved in the motor. It is a first step but only a very tiny one.