Evolution in varying environments

[Roger Critchlow-2]

Back to complexity for a moment.

Here are two open access preprints from PNAS that I found while looking for
the new map of Angkor Wat.

The first is about speeding up artificial evolution by changing the
environment:

      http://www.pnas.org/cgi/content/abstract/0611630104v1

I haven't read enough to see how they identify the "modules" into which they
decompose the phenotype so they can select different subsets of modules on
each environmental change.

The second, which was published a day earlier, is about the same thing, only
for real.  The environment in Madagascar is diverse, but the diverse regions
all share an unpredictable rainfall through the year and year to year.  This
unpredictability is proposed to contribute to the unusual diversity of
mammals found.

     http://www.pnas.org/cgi/content/abstract/0704346104v1

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[Marcus G. Daniels]

Roger Critchlow wrote:
> I haven't read enough to see how they identify the "modules" into
> which they decompose the phenotype so they can select different
> subsets of modules on each environmental change.
It looks function composition to me.   g(f(x,y),h(w,z))  where they,
say, swap around the order of f and h in g.   In that way the evolved
boolean network must evolve to remember how g, f, and h work
independently to be efficient and coping with changes in ordering.  
Intuitively, it makes sense that changing the composition of functions
from time to time would make each function be more robust.

[Gus Koehler-2]

"modularity--the attempt to understand systems as integrations of partially
independent and interacting units..." See: Callebaut and Rasskin-Gutman
(2005). Modularity: Understanding the Development and Evolution of Natural
Complex Systems.  MIT Press.


Gus Koehler, Ph.D.
President and Principal
Time Structures, Inc.
1545 University Ave.
Sacramento, CA 95825
916-564-8683, Fax: [phone]
Cell: 916-716-1740
www.timestructures.com
 

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf
Of Marcus G. Daniels
Sent: Tuesday, August 14, 2007 4:22 PM
To: The Friday Morning Applied Complexity Coffee Group
Subject: Re: [FRIAM] Evolution in varying environments

Roger Critchlow wrote:
> I haven't read enough to see how they identify the "modules" into
> which they decompose the phenotype so they can select different
> subsets of modules on each environmental change.
It looks function composition to me.   g(f(x,y),h(w,z))  where they,
say, swap around the order of f and h in g.   In that way the evolved
boolean network must evolve to remember how g, f, and h work
independently to be efficient and coping with changes in ordering.  
Intuitively, it makes sense that changing the composition of functions from
time to time would make each function be more robust.

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