Re: Ears under pressure. Was Re: Aquatic ape theory
H. M. Hubey (hubey@pegasus.montclair.edu)
26 Oct 1995 23:43:34 -0400
hoelzer@unr.edu (Guy Hoelzer) writes:
>While Dr. Duncan's comment was rather terse, I agree completely with his
>point. Both Thomas Clarke and H. M. Hubey are incorrect in suggesting that
>only neutral or adaptive mutations will increase in frequency, possibly to
>the point of fixation. In relatively small populations maladaptive
>mutations can increase in frequency and even go to fixation due to random
>sampling of alleles from the previous generation. This is "genetic drift",
>which is much more than a meaningless term.
You are right, strictly speaking. I was using the words in the
same fuzzy sense as used by others. Yes, in small populations,
the effects are always more drastic.
In fact, this seems to be the case in General System Theory
since it's observed in Thermodynamics and also in Linguistics.
And yes, the fixation time etc has been computed by several
people in different ways and can be found in relatively
accessable (to me) books such as Roughgarden, Th. of Pop.
Genetics, and Kojima (ed), Math. Topics in Pop. Genetics.
>mutations and many maladaptive mutations. Clarke and Hubey are correct
>that strongly deleterious mutations will rarely be driven to fixation by
>drift. Nevertheless, it is probably not uncommon for drift to cause
>maladaptive evolution.
The trick is that I still think that "eventually" the "maladaptive"
mutations will always wind up wiping out the species. The
problems are with "eventually" and "maladaptive". First "maladaptive"
can only be relative to niche and habitat, which can change.
Secondly, if we have no independent way of telling what is
"maladaptive" then it's circular. It's like saying "those
that survive are the fittest" as well as "the fittest survive".
There's no explanatory value.
--
Regards, Mark
http://www.smns.montclair.edu/~hubey
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