Re: Randomness and complex organization via evolution

From: Chris Cogan (ccogan@telepath.com)
Date: Sat Jul 15 2000 - 00:09:10 EDT

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    At 04:10 PM 07/13/2000, you wrote:

    >Susan;
    > >The scientific method only works on that
    > >which is directly or indirectly observable.
    >
    >Bertvan:
    >Such as evolution?

    Chris
    Yes. ". . . directly or *indirectly* observable." Besides, some evolution
    *is* directly observable, as you probably know. We can observe genetic
    variations and we can observe organisms being killed off by environmental
    factors, leaving behind populations that have a *different* total gene pool
    than previously, a *different* "median" genome.

    Unless someone can show that there is something to *prevent* so-called
    "microevolution" from being cumulative (and we can *directly* observe
    cumulative variations as well, by *directly* observing that genomes that
    resulted from variations can be varied still *more* in subsequent
    generations -- something that is observed at *all* levels of life, from
    bacteria to the highest primates -- and even in pseudo-life such as viruses.

    Further, if there *were* such "barriers" between species in general, or if
    there were some rigid "median" for each species, genetic statistics would
    absolutely have to be *severely* skewed towards such medians, *regardless*
    of environmental factors. Broccoli, cauliflower, and Brussels sprouts
    would all be impossible, because they evolved, *within human history*, from
    some common ancestor (I don't remember what that ancestor was/is). Right
    now, they all have their own "median" genome(s).

    In some special cases, there might be a kind of median of some sort that is
    unusually stable (if there is a corrective mechanism that keeps the genome
    from varying or that corrects the genome in subsequent variations). But
    even these are not absolutely stable and rigid. Further, such a mechanism,
    if it is *too* "good," will cause the species to go extinct as soon as it
    meets conditions that it is not currently adapted to. What Jones and the
    rest must show is that there *is* such a rigid mechanism and yet (via pure
    logical magic) make it compatible with the fact that there is no observed
    *general* severe skewing of genetic statistics around genetic medians
    except insofar as the *environment* serves as a *corrective* mechanism,
    selecting *out* those genomes that vary too much from the local optimum.

    Pleiotropy and genetic cross-linking can *slow* evolution, by requiring, in
    some cases that morphological features controlled by one gene become
    controlled by separate genes, and that cross-linkages be broken, but there
    is no evidence of a *rigid* barrier to macroevolution. Since the ID folks
    are not *merely* claiming that they don't believe in macroevolution but are
    claiming to *know* that it does not occur, they have the obligation to
    carry the burden of proof.



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