>...I, and I am sure others, would
>appreciate it if anyone who is able to do so, preferably a biologist, but
>anyone, would attempt to clearly describe a set (or sets) of circumstances
>that would reasonably indicate what a limitation on morphological change
>really means, and the conditions that should be met in showing the
>limitation does not hold.
>
>For instance, one might say that a change of species could not occur
>within a specified number of generations, or a specified time period, for
>there to be a clear limitation to morphological change...
>
>There has been enough posturing! So let's get beyond that.
I concur. I have mostly watched this debate from the sidelines, and
watched it with a sense of wonderment that it could continue so long
without the two parties agreeing just what they are debating over. Glenn
has argued that there are no limits on variation, leaving himself open to
claims by Stephen and others that, for example, the inability of an
adaptive process to achieve significant improvement near an optimum is in
itself a limit on variation. That strikes me as a trivial objection -- not
the kind of limitation that would be considered news by the evolutionary
biology community. But nevertheless, it is a limitation on variation. Jim
asks for scientific papers documenting the lack of limitations on
variation. Scientific papers generally aren't that broad. You _can_ find
papers that establish that certain kinds of variation have been observed.
Since a cursory look at genetics might convince one that there _are_ limits
to variation, papers documenting that some of these limits have been
crossed are significant.
For starters, you might consider just what is meant by a limit on
variation. Do we admit natural selection as a limiting factor, or do we
say that a variation is restricted against only if its occurence causes the
individuals carrying it to die? Or do we say a variation is restricted
against only if it cannot even occur?
Bill Hamilton | Vehicle Systems Research
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