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Darwin-L Message Log 5:76 (January 1994)

Academic Discussion on the History and Theory of the Historical Sciences

This is one message from the Archives of Darwin-L (1993–1997), a professional discussion group on the history and theory of the historical sciences.

Note: Additional publications on evolution and the historical sciences by the Darwin-L list owner are available on SSRN.


<5:76>From ahouse@hydra.rose.brandeis.edu  Fri Jan 14 10:16:31 1994

Date: Fri, 14 Jan 1994 11:21:45 -0500
To: darwin-l@ukanaix.cc.ukans.edu
From: ahouse@hydra.rose.brandeis.edu (Jeremy Creighton Ahouse)
Subject: Re: On neoDarwinism 2

>On neoDarwinism 2
>Thanks to Bob O'Hara, Ron Amundson and Dave Rindos for their responses.
        Yes, thank you and also to John Wilkins.

>I was indoctrinated to the view
>"selection ueber alles" and find it uncomfortable when someone makes the
>claim that, as I recall Brooks and Wiley to say (book not to hand), selection
>is less important than other forces/states/processes in determining
>evolutionary change.

        I am fascinated by these kinds of discussions.  It is always the
case that there are enough dark corners around the new synthesis that
"alternate" suggestions (not "selection ueber alles", not simple linneage
bifurcation, not Weismann doctrine consistent, etc...) can be made to fit.
And few inclusionists are as honest about their indoctrination as John is.

        Still I want to inject this discussion with a little David Raup.  A
good review of what I will describing is Raup's _Mathematical Models of
Cladogenesis_ in Paleobiology 11(1), 1985, pp42-52.  The bottom line from
this work, for me, is that trivial models of cladogenesis result in
patterns that match some examples of paleontological data.  Here is a quote
from that paper.

        "Any monophyletic group, or clade, owes its existence to the
interplay of two processes: lineage branching (speciation) and lineage
termination (species extinction).  If the incidence of branching exceeds
termination, the clade will survive and perhaps flourish, but if
termination exceeds branching for a sufficient time, extinction of the
clade is inevitable."

        From this description Raup and Sepkowski (and others) played with
simple  models (= homogeneous in time => extinction and speciation rates
are constant in a group).  And found that some of the branching diagrams
thus generated were difficult to separate from known records.  Does this
mean that micro-evolution and selection as prime mover are defunct notions?
No.  But it does suggest (require?) a more sophisiticated approach to
telling the tale of current abundance and distribution.  And in that story
the primacy of selection may not be the best organizing principle.

        - cheers,

        - Jeremy

:::::::::::::::::::::::::::::::::
        Jeremy Creighton Ahouse
        Biology Dept. & Center for Complex Systems
        Brandeis University
        Waltham, MA 02254-9110

        (617) 736-4954
        email: ahouse@hydra.rose.brandeis.edu
        Mail from Mac by Eudora 1.3.1 RIPEM/PGP accepted.

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