Posted by
Phil Henshaw-2 on
Oct 06, 2008; 11:06pm
URL: http://friam.383.s1.nabble.com/Relaxed-selection-tp1301731p1302178.html
Jochen,
That concept of alternating opportunistic and constrained developmental
phases, 'relaxed' then 'fierce' selection regimes, sounds like a statistical
version of the behavioral model that growth begins from minute beginnings in
an environment without constraint except itself. When that kind of growth
exhausts its initially unlimited opportunities and runs into constraints
then integrating with an environment becomes the selective test. That
switch from just freely expanding on the past to adapting in relation to
emerging future constraints corresponds to immature growth followed by
maturation at climax (¸¸.´¯¯) and their very different selection regimes.
The behavioral 'trick' needed to make that statistical idea into a
functional description of a new mode of evolution is letting the system be
active partner and the environment a passive one. If the system actively
explores its environment, just like you see virtually all living things are
visibly doing whenever they're not sleeping, then the form of the system
doesn't need to be present in the environment before the system develops.
That's always been the real undiscussed problem with the normal Darwinian
model. It's that individual exploratory habit of a system that makes
opportunistic development such as Deacon describes physically possible.
That's what my plankton paper shows is happening with G. tumida, a series of
progressive evolutionary spurts and collapses on the way to the
stabilization of a new form, clear active individual behavior in a passive
environment.
Phil
> -----Original Message-----
> From:
[hidden email] [mailto:
[hidden email]] On
> Behalf Of Jochen Fromm
> Sent: Monday, October 06, 2008 3:34 PM
> To: The Friday Morning Applied Complexity Coffee Group
> Subject: [FRIAM] Relaxed selection
>
> 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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