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From: dubois@uwmacc.UUCP (Risky Rat)
Newsgroups: net.origins
Subject: Re: No Cigarettes, Please
Message-ID: <1361@uwmacc.UUCP>
Date: Mon, 5-Aug-85 14:54:30 EDT
Article-I.D.: uwmacc.1361
Posted: Mon Aug  5 14:54:30 1985
Date-Received: Wed, 7-Aug-85 00:51:45 EDT
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>> [Paul DuBois]
>> Witness also the great importance attached to natural selection by many
>> on this net.  But how important is it in recent evolutionary theory?
>> Not very, in a number of instances.  Michael Lonetto has shown evidence
>> that he knows this.  How many others?  Rich is (apparently) still in
>> the dark ages, carrying this (apparently) *unexamined conviction*
>> around.  Mike H might be, but I doubt it; I suspect that he was trying
>> to clarify what Rich said, rather than defend it as his own position.

> [Wayne Throop]
> I don't follow this at all.  Perhaps some of the enlightened, such as
> Michael Lonetto, would let me in on the secret.  In what way is natural
> selection unimportant to "recent" evolutionary theory.

I misspoke somewhat.  What I should have said, was that natural
selection is considered unimportant more and more in regard to
*speciation* - not evolution in general.  (My reference to Michael L
was in regard to his posting on speciation in Drosophila.)

Anyway, to clarify, my favorite passage comes from:

    Stephen Jay Gould, "Is a new and general theory of evolution
    emerging?", _Paleobiology_, 6(1), 1980, 119-130.

    The control of evolution by selection leading to adaptation lies at
    the heart of the modern synthesis.  Thus, reproductive isolation,
    the definition of speciation, is attained as a by-product of
    adaptation -- that is, a population diverges by sequential
    adaptation and eventually becomes sufficiently different from its
    ancestor to foreclose interbreeding.  (Selection for reproductive
    isolation may also be direct when two imperfectly-separate forms
    come into contact.) But in saltational, chromosomal speciation,
    reproductive isolation comes first and cannot be considered as an
    adaptation at all.  It is a stochastic event that establishes a
    species by the technical definition of reproductive isolation.  To
    be sure, the later success of this species in competition may
    depend upon its subsequent acquistion of adaptations; but the
    origin itself may be non-adaptive.  We can, in fact, reverse the
    conventional view and argue that speciation, by forming new
    entities stochastically, provides raw material for selection.
                                                       [page 124]

I highly recommend this paper.  It is my impression that Gould is very
popular in this newgroup but that few have read more than his popular
books and/or his essays in Natural History.

-- 
                                                                    |
Paul DuBois     {allegra,ihnp4,seismo}!uwvax!uwmacc!dubois        --+--
                                                                    |
Ritual and Ceremony:  Life Itself.                                  |