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From: friesen@psivax.UUCP (Stanley Friesen)
Newsgroups: net.bio
Subject: Re: Orphaned Response
Message-ID: <1190@psivax.UUCP>
Date: Fri, 16-May-86 15:45:33 EDT
Article-I.D.: psivax.1190
Posted: Fri May 16 15:45:33 1986
Date-Received: Mon, 19-May-86 05:28:03 EDT
References: <311@dg_rtp> <1188@umcp-cs>
Reply-To: friesen@psivax.UUCP (Stanley Friesen)
Organization: Pacesetter Systems Inc., Sylmar, CA
Lines: 31

In article <1188@umcp-cs> mangoe@umcp-cs writes:
>
>The question of whether there is goal-oriented evolution is not moot, and it
>simply isn't a question of semantics either.  The "punctuated evolution"
>school, in its descriptive explanation, begs the question of why certain
>morphological changes seem to happen almost instantaneously.  I would
>suggest that it is possible that there is some impetus which actively seeks
>the completion of the transformation.  THis is rather different from an
>explanation which argues that the dispersive force is simply mutation, and
>that the favorable changes are simply the ones which persist.  The second is
>a more orthodox explanation, but orthodoxy is no guarantee of truth in
>science.
>
        While "radical" puncuated evolution theory does indeed beg the
question of mechanism, there is really little evidence for its claims.
In fact there is much counter evidence supporting more gradual
changes. Part of the problem of course is that from a geological point
of view "almost instantaneously" can mean 10's of *thousands* of years.
The less extreme versions of PE, such as proposed by Ernst Mayr, do
not require any new or unusual mechanisms, the standard population
genetics effects combined with selection are deemed to be sufficient
to explain the observed rates of change during speciation. Personally
I think we are headed to a new synthesis in which many of the better
concepts from PE are fused with the more stable components of "orthodox"
evolutionary theory.
--

                                Sarima (Stanley Friesen)

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