Re: Group selected altruism - (was: Hamilton's rule)


Guy Hoelzer wrote:
> in article dlvnf0$mco$1@xxxxxxxxxxxxxxxxxxx, Jim McGinn at
> jimmcginn@xxxxxxxxx wrote on 11/22/05 10:19 AM:
>
> > All that is necessary for group selection is that there situational factors
> > that prevent or reduce gene flow between groups, as Catherine described, and
> > situational factors that cause differential survival/reproduction between the
> > groups, as Catherine also described.
>
> Jim,
>
> I am surprised that you of all people have advocated an unrealistic
> constraint on the potential for group selection. What difference could it
> possibly make to group selection to "prevent or reduce gene flow between
> groups"?

I'm surprised that you're surprised.

Because without it any selective benefits or detriments that
result from the behavior of a member of a group cannot be
focussed on the group. IOW, without this assumption groups
cannot be biological entities; without some kind of relative
reduction or elimination of gene flow between groups you,
essentially, can't have group selection. From this we get the
following rule: one of the prerequisites for group selection is
that you have some kind of situational factor that causes he
existence of biological groups by way of reduction or
elimination of gene flow between groups.

I employed this rule (very effectively IMO) in the context of my
hypothesis on hominid evolution. Given the observance of very
obvious group selected traits and behaviors in our species, I
reasoned that the earliest years of hominid evolution (the
transition from our chimpanzee-like last common ancestor to the
first hominids) would have situational factors that dictate a
reduction is gene flow between groups. And in examining
descriptions of the fossil evidence it became apparent that in the
earliest years of hominid evolution we see an shift in the climate
from a rainforest habitat to a monsoon forest habitat. As a result
of the dry season of a monsoon climate much of the rainforest
disappeared. What remained was patches of forest habitat
surrounded by relatively treeless habitat that was dominated by
large predators. The net effect was that our earliest ancestors were
now split up into geographically defined groups in which gene flow
between them was reduced or eliminated. Thereby this particular
prerequisite for group selection was achieved.

(For more on my hypothesis of hominid evolution you can go to
Google Groups and do a search in sci.anthropology.paleo on
Ecological Gatekeeper Hypothesis.)

> Isn't that analogous to arguing that it is necessary for
> individual selection that gene flow between individuals (sex) is prevented
> or reduced?

Yes.

> IMHO, gene flow is utterly irrelevant in both instances.

I don't see how this is possible.

Jim


.

Relevant Pages

  • Re: Reviving group selection
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  • Re: Group selected altruism - (was: Hamiltons rule)
    ... >> in article dlvnf0$mco$1@xxxxxxxxxxxxxxxxxxx, Jim McGinn at ... >> constraint on the potential for group selection. ... >> possibly make to group selection to "prevent or reduce gene flow between ... of biological inheritance. ...
    (sci.bio.evolution)
  • Re: How Cooperation Survived in a Cheaters World
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  • Re: Group selected altruism - (was: Hamiltons rule)
    ... > groups, as Catherine also described. ... constraint on the potential for group selection. ... possibly make to group selection to "prevent or reduce gene flow between ... individual selection that gene flow between individuals is prevented ...
    (sci.bio.evolution)
  • Re: Beyond the Savanna Mentality
    ... Jim McGinn wrote: ... exceptionally difficult to reconcile with group selection models). ... >> mechanisms in any detail with which to address this. ...
    (sci.anthropology.paleo)
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