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From: g-rh@cca.CCA.COM (Richard Harter)
Newsgroups: soc.men,sci.bio
Subject: Re: Sexual selection
Message-ID: <25701@cca.CCA.COM>
Date: 18 Mar 88 19:18:22 GMT
References: <1566@mmm.UUCP> <3138@arthur.cs.purdue.edu> <1164@microsoft.UUCP> <2402@saturn.ucsc.edu> <2686@calmasd.GE.COM>
Reply-To: g-rh@CCA.CCA.COM.UUCP (Richard Harter)
Organization: Computer Corp. of America, Cambridge, MA
Lines: 42


>I would guess this is at least partly true, but my feeling is that the
>marked dimorphism  in humans is  the result of  physical adaptation to
>social roles.  In  most  primitive societies (pre-agricultural)  women
>are gatherers and men are hunters (and to a lesser extent women "hide"
>with the children and men go out to confront  the "enemy").  The women
>care for the children and gather food (the most reliable  food source)
>and  men hunt  (less  reliable but  greater  quantities when  they are
>successful).  The body forms of present day humans still  reflect this
>adaptation rather well,  men are relatively  strong and "brawny",  but
>tend toward  lower endurance, the women  are less muscular but tend to
>be more able to carry out low-level activity for far longer than men.

	Unlikely -- it is probably more the other way around -- social
roles adapt to physical differences.  Primate dimorphism is general in
the great apes and rather old -- it goes back a long ways.  One has to
consider the possibility that dismorphism is (at this point) simply built
in.   Organisms are not infinitely malleable; selection works with existing
mechanisms.  It may, in effect, be hard to select against dimorphism
once the mechansim is thoroughly in place.

	Another factor that should be considered is that selection in
humans and pre-humans operated differently than it does in baboons,
for example.  In baboons a male gets to breed if it is an alpha male.
Selection is strong for alpha male traits.  In humans a male gets to
breed if he can find a mate.  Most males get to breed; only the marginal
ones do not.  Selection is much weaker and is mostly negative selection
against non-survival traits and those traits that lead males either not
to breed or not to be an acceptable mate to any female.  A major class
of such traits is 'social acceptability' -- any individual that cannot
be accepted in the tribe has low prospects for being part of the breeding
pool.

	In a general way there may be something to what you say --
social roles can condition selection.  The problem with that idea is
simply that it is easier to alter social roles to fit physiology than
it is to alter physiology to fit social roles, in humans, at least.
-- 

In the fields of Hell where the grass grows high
Are the graves of dreams allowed to die.
	Richard Harter, SMDS  Inc.