Indeed, We could say, by means of a monist metaphysics, that, ones the fish became à vertebrate, a new "whole" will be created. So there is unescapably transformation of certain organs of the old in new, fitter organs for the new whole. There is thus,
1. A new coherent (vis à vis the new environment) constitution of many parts. 2. Tranformation of certain parts (organs) 3. Emergence of a new (internal-consistent) whole. Because I'm not a biologist, can somebody explane how biological transformation occurs by intermediate phases in order to become the new whole? Thank you. Julien Libbrecht. -----Oorspronkelijk bericht----- Van: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Jan Bernheim Verzonden: vrijdag 21 januari 2005 19:54 Aan: evolcomp@listserv.vub.ac.be Onderwerp: Re: [ECCO] Re: Irreducible Complexity Superb! Can anyone put me straight on 'accelerations' or 'stagnations' in evolution? In immunology, there is the 'Generator of Diversity' (GOD), a mechanism to in the thymus generate the (almost) infinite diversity of T-cell specificities towards antigens (bacteria, viruses...) It is a 'machine' generating minor changes in the gene of the hypervariable part of the antibody molecule. These clones then get selected by the environment. Jan At 17:28 21/01/2005, you wrote: >>Having just >>read all of Behe's examples I could most humorously relate to the >>article below called "Irreducible Complexity Demystified." >>by <mailto:pdunkelberg _at_>earthlink.net>Pete Dunkelberg where he does a >>most excellent job of totally >>destroying the entire concept of "Irreducible Complexity." >>It appears, in the end, to boil down to two major problems with Behe >>(among many others.) The first is the way Behe "conceptualizes" >>biological "parts" creating a non-existent state of biological existence. >>The second is the result of truly sloppy scientific work on the part >>of Behe. > >To me, the essential argument against Behe's idea that "irreducible >complexity" cannot evolve, is that Behe ignores or dismisses "indirect" >evolution, i.e. evolution following some circuitous route towards a >particular function or organization, by evolving a variety of other >functions or organizations that at first sight don't seem to have anything >to do with the function in focus, but that eventually produce that >function as a kind of "side-effect". > >Stephen Jay Gould summarized this idea using the term "exaptation", i.e. >an evolved featured is not initially adapted to perform a particular >function A, but a wholly independent function B. But then it turns out >that the organization that allows B can also be used to do A, with some >minor modifications. And finally, perhaps because the environment has >changed, it turns out that B is no longer necessary, so the full selective >pressure goes towards optimizing the feature for A. > >But then an intelligent design theorist comes along, sees how beautifully >the feature performs A, and observes that a more primitive version of this >feature would not have been able to perform A. Therefore, he concludes, >the feature could not have evolved, and must have been designed. But he >ignores the possibility that the primitive version might have performed >the wholly different function B. > >A classic example of exaptation are the lungs of land-living vertebrates, >whose function is to extract oxygen from the air (A). They evolved from >the swimbladder used by fish to keep their vertical position in the water >(B). But once the first fishes started to live on the land, they no longer >had a need for a swimbladder, and so function B was lost. However, since >the swimbladder contained air, it could be easily adapted to the function >of extracting oxygen from that air. The gills, on the other hand, which >fish use to extract oxygen from water, could not be adapted to air, and so >were lost. > >Another simple example mentioned by Pete Dunkelberg is the tail used by >cows merely to swat flies, where it is obvious that tails initially >evolved for very different purposes. > >The essential point is that evolution does not distinguish between >"direct" and "circuitous" routes towards evolving some feature: it merely >moves from the present state to a state that is locally more fit, but what >is fit depends on a multitude of factors and a constantly changing >context. Therefore it is difficult for us as observers to recognize a >concrete direction in the process. When we try to imagine how the process >might have taken place, we are biased to look in a particular direction, >namely the one where the function we are interested in can be reached via >the shortest, most direct route. But then we often find that there is an >insurmountable obstacle when we try to follow that route. Yet, evolution >doesn't even notice the obstacle, as it cannot look ahead, and has no bias >towards short, direct routes: it will just take any route going anywhere, >with the only condition that none of the states along that route reduce >fitness. >-- > >Francis Heylighen >Evolution, Complexity and Cognition group >Free University of Brussels >http://pespmc1.vub.ac.be/HEYL.html --- Incoming mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.809 / Virus Database: 551 - Release Date: 9/12/04 --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). 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