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Re: Relaxed selection

Posted by Phil Henshaw-2 on Oct 09, 2008; 1:21pm
URL: http://friam.383.s1.nabble.com/Relaxed-selection-tp1301731p1312077.html

I'll look up David Green.   There have been several directions that people
have taken to the fast/slow evolution evidence originally clarified by
Stephen J Gould.   Kirschner and Gerhart's approach in "The Plausibility of
Life" is somewhat like the one I proposed, that the speed control is not
variation in the selective pressure but variation in development rates for a
local exploratory process.  That's quite clearly what's evident in the form
of transition seen with that plankton of mine.   Reasoning it that way does
present some other challenges, of course, but does have the advantage of
getting rid of the highly inelegant notion that the form of new creatures
pre-exists as a kind of negative image in their potential environments.

Phil

> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On
> Behalf Of Russell Standish
> Sent: Thursday, October 09, 2008 5:55 AM
> To: The Friday Morning Applied Complexity Coffee Group
> Subject: Re: [FRIAM] Relaxed selection
>
> David Green proposed somewhat similar ideas back in around
> 2000. Someone else (I forget who now) mentioned it again in a slightly
> different form within the last year in an Artificial Life article. I
> tried running an experiment implementing this idea using Tierra, but
> have found that I need to reimplement Tierra, as computers are now so
> fast that Tierra's genebanker code overflows within a day or so of
> runtime.
>
> I hope to get around to this over the next year, hopefully before the
> Budapest ECAL conference.
>
> Cheers
>
> On Mon, Oct 06, 2008 at 09:33:39PM +0200, Jochen Fromm wrote:
> > One of the things I am interested in is how nature
> > creatures complex things. The latest New Scientist
> > (from 27 Sep. 2008) has an article named "As if from
> > nowhere" about the topic of "relaxed selection", a
> > concept invented by Terry Deacon. Terry Deacon is
> > an anthropology professor at Berkeley.
> >
> > According to Deacon, relaxed selection is a special
> > form of natural selection, where the selection
> > pressure and the competition is low (i.e. where
> > natural selection itself is nearly absent), and the
> > variety of traits which are able to survive and
> > reproduce is high. When the selection pressures lift,
> > genomes go wandering and new, unexpected traits may
> > arise. I think if there is a "relaxed selection",
> > then one can also speak of a "fierce selection":
> > a natural selection with fierce competition when
> > the climate is harsh and the food is sparse. Under
> > this conditions only the best, well adapted individuals
> > survive.
> >
> > Does natural selection occurs in different degrees?
> > During "relaxed selection", the system enters an
> > exploration phase: the chances of finding new
> > configurations, traits and features are higher.
> > The selection pressure for a species to remain
> > in the corresponding niche is lower.
> > During "fierce selection", the system enters an
> > exploitation phase: chances of optimizing existing
> > configurations, traits and features are higher.
> > The selection pressure for a species to remain
> > in the corresponding niche is higher.
> >
> > What do you think of "relaxed selection" ?
> > Is Deacon onto something?
> >
> > -J.
> >
> >
> >
> >
> >
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>
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> A/Prof Russell Standish                  Phone 0425 253119 (mobile)
> Mathematics
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> FRIAM Applied Complexity Group listserv
> Meets Fridays 9a-11:30 at cafe at St. John's College
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============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org