Darwin-L Message Log 1:140 (September 1993)

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.

<1:140>From LANGDON@GANDLF.UINDY.EDU  Thu Sep 16 08:21:55 1993

Date: Thu, 16 Sep 1993 08:21:55 -0500
To: darwin-l@ukanaix.cc.ukans.edu
Subject: Re: Lamarkianism in linguistic change

In message <Pine.3.07.9309151636.A6382-b100000@irwin.cs.uoguelph.ca>  writes:

>  As for the progression from simple to complex, I could
>  show you a whole host of insects that for one reason or another have
>  gone from a complex 'generalist' form to a comparatively simple
>  'specialist' form.  If complexity is not selected for (and complexity
>  tends to be energetically expensive) it will disappear.  It could
>  be argued that in fact the trend is towards simplicity and not
>  complexity as highly complex organisms lose unneeded aspects of
>  their morphology and behavioral repitoire as they specialise into
>  particular niches.  Parasites and parasitoids are good examples of
>  this loss in complexity.
>  On the other hand I remember reading something to the effect that
>  generalist species do better in the long run then specialist species...

I don't think that generality and specialization represent the same spectrum as
simplicity/complexity. I have found that generality generally means selection
to maintain a compromise morphology, satisfying many competing functional
demands simultaneously to some degree of effectiveness. Specialization
represents a shift along the spectrum of compromise so that some demands of
increasing importance are met more effectively and others, of decreasing or
vanishing importance, are met less effectively. For example, in the evolution
of the catarrhine foot, primitive generality meant a broad spectrum of
potential behaviors in a broad range of substrates (climbing, walking, running,
etc.) while later specialization emphasized EITHER slower climbing (apes) OR
running/leaping (monkeys) at the cost of the other. I don't see these as
changes in level of complexity.

The evolutionary trend is toward specialization in many cases when competition
demands greater effectiveness of a particular function and/or when the
environment is stable and uniform enough to favor a narrower niche over a long
period of time. Generality is favored if the environment is changing or the
niche is broad, because of the potential for resource switching and, in the
long run, because the generalists have a greater potential for specializing to
meet a different environment.

I don't think this informs the discussion on complexity.

JOHN H. LANGDON         email  langdon@gandlf.uindy.edu
DEPARTMENT OF BIOLOGY       phone (317) 788-3447

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