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

in article dm2s1n$2cg6$1@xxxxxxxxxxxxxxxxxxx, Jim McGinn at
jimmcginn@xxxxxxxxx wrote on 11/23/05 2:55 PM:

> 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.
>

[snip comments on human evolution]

>> 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.

I agree with you that boundaries must exist around systems that largely
isolate the dynamics of the system if a process is to manifest at the level
of the system (e.g., natural selection). However, your position assumes
that genetics is the sole conduit of heredity in biological systems. I
don't think it is controversial at all to claim that there are other modes
of biological inheritance (e.g., epigenetics, cultural inheritance). Even
if genetic elements flow in and out of a group without restriction, it
remains possible that exchange among groups is restricted with regard to
other modes of inheritance. This setting permits a group-level
manifestation of natural selection even without a restriction to gene flow.

Guy


.

Relevant Pages

  • Re: Reviving group selection
    ... > populations by sexual recombination. ... No theoretical argument against group selection is based on within-group ... >> says absolutely nothing about how such variation arises. ... > mutations and insufficient gene flow between them. ...
    (sci.bio.evolution)
  • 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 ... reasoned that the earliest years of hominid evolution (the ...
    (sci.bio.evolution)
  • Re: How Cooperation Survived in a Cheaters World
    ... Thomas Flatt, a postdoctoral research associate at Brown, was ... I didn't notice where it said that gene flow between groups is ... Good old 'bog standard' group selection doesn't work. ...
    (sci.bio.evolution)
  • 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: Group selected altruism - (was: Hamiltons rule)
    ... the important thing for a general theory of multilevel selection is ... > that at least one mode, any mode, of inheritance is manifested. ... >> some kind of concensus on group selection. ...
    (sci.bio.evolution)