Re: Three roles of "the population".

From: Joe Felsenstein (joe_at_removethispart.gs.washington.edu)
Date: 02/25/05 

Date: Fri, 25 Feb 2005 13:43:51 -0500 (EST)

In article <cvm8f1$1fbv$1@darwin.ediacara.org>,
Perplexed in Peoria <jimmenegay@sbcglobal.net> wrote:
>It occurs to me that some of the confusion regarding kin selection and
>group selection occurs because of a failure to distinguish the three
>different roles that "the population" plays in our models. There
>are really three different "kinds" of populations.
>
>One is the "breeding population".
....
>A second is the "competitive population".
...
>The third is the "social population". In a model of random social
>interactions, this is the population from which the recipient for
>a donor is randomly selected. Clearly, as was recognized by Hamilton
>in 1964, forgotten by him in 1970, but remembered by him by the
>time of "Narrow Roads", the "social population" must be smaller
>than the "breeding population" if kin selection is to promote
>indiscriminate altruism within the "social population".
>
>Of course, all of the above is a gross oversimplification. Each
>of these "populations" is part of a "meta-population".

This is an excellent exposition of the issues involved in modelling
organisms as being in "populations". Of course the third definition
involving social interactions describes a group that may not even be
thought of as a population, such as a group of siblings.

The word population gets ambiguous also with metapopulations (as
Perplexed has indicated) as then it is somewhat unclear whether
the "population" we talk of is the local population or the metapopulation. 

-- 
Joe Felsenstein         joe@removethispart.gs.washington.edu
 Department of Genome Sciences and Department of Biology,
 University of Washington, Box 357730, Seattle, WA 98195-7730 USA

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