Flaw in denial of "group selection" principle in evolution discovered?

From: Eric Hawthorne <egh.domain.name.hidden>
Date: Sun, 01 Feb 2004 16:11:26 -0800

Blast from the recent past.
This is pertinent to the previous discussions on evolution
as a special case of emergent-system emergence.

It was argued that "group selection" effects have been discredited in
evolutionary biology. I counterargued that denying the possibility of
a selection effect at each more-and-more complex system-level in
a multi-layer complex-ordered emergent system (such as ecosystems,
biological species etc) denies the likelihood of spontaneous emergence of
those complex systems at all.

I think I've found the source of the confusion regarding group selection
effects. It goes like this:

A species can evolve a "group-benefit" behaviour so long as the development
of the behaviour does not, on average, reduce the reproductive success
of individuals
that engage in the group-benefit behaviour, and so long as the behaviour
does
confer, on average, a benefit to the reproductive chances of each
individual in
the well-behaving group.

The key is in how we interpret "average". The question is whether an
individual
organism always acts "in each short-term encounter" in a manner which
maximizes their
chance of survival-to-breeding-age IN THAT ENCOUNTER, or whether it is
possible
for the individual to wager that taking a slight risk now (and
believing or observing that
others will also do so) will lead to a better chance that the individual
will survive ALL
ENCOUNTERS from now up until it breeds. The organism doesn't have to be
smart enough
to believe in this wager. It is sufficient that the wager be on average
beneficial to the
individual.In that case, through repeated trials by multiple
individuals, the behaviour
which is group-adaptive and individually "lifetime-average" adaptive can
evolve.

BECAUSE THE EVOLVABLE "GOAL" IS NOT SIMPLY TO MAXIMIZE THE
CHANCE OF SURVIVAL OF AN ORGANISM OF THE NEXT SHORT-TERM ENCOUNTER.
THE "GOAL" IS TO MAXIMIZE THE PROBABILITY OF SURVIVAL OF THE SUM TOTAL
OF ALL OF THE ORGANISM'S ENCOUNTERS UP TO WHEN THE ORGANISM REPRODUCES.

So it is just a time-scale misunderstanding. Group-adaptive behaviours
increase the member's
probability of surviving to reproductive age, even if they slightly
increase the chance of the
indvidual losing some particular encounter.

True "extreme" altruistic behavior which conveys CERTAINTY of death in a
single encounter
may not fit into this model, but it can be argued as to whether the
altruistic individual "believes"
they are going to die "for certain" in many incidents or not, or whether
they hold out "faint hope"
in which case the argument above could still hold. In any case, true
"certain death" altruistic behaviour
is an extreme anomoly case of group-adaptive behviour. Most
group-adaptive behaviours are
not of that kind, so "extreme, definitely fatal" altruism is not a good
model for them.

Eric
Received on Sun Feb 01 2004 - 19:19:16 PST