Xref: utzoo soc.men:3002 sci.bio:968
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From: g-rh@cca.CCA.COM (Richard Harter)
Newsgroups: soc.men,sci.bio
Subject: Re: Sexual selection
Message-ID: <25443@cca.CCA.COM>
Date: 11 Mar 88 07:42:43 GMT
References: <1566@mmm.UUCP> <3138@arthur.cs.purdue.edu> <1164@microsoft.UUCP> <3455@medusa.cs.purdue.edu> <3232@zeus.TEK.COM> <13400@sri-unix.SRI.COM> <913@bingvaxu.cc.binghamton.edu>
Reply-To: g-rh@CCA.CCA.COM.UUCP (Richard Harter)
Organization: Computer Corp. of America, Cambridge, MA
Lines: 51

In article <913@bingvaxu.cc.binghamton.edu> vu0112@bingvaxu.cc.binghamton.edu (Cliff Joslyn) writes:

>Yes, this seems to be the only possibility.  Nor should we be surprised:
>in classical evolutionary theory it is described as "sexual selection."
>It is used to describe various and sundry typcially male charactersitics
>as peacock tails and other silly and seemingly useless features.  While
>I've read about this, it has never made any sense to me.  

>I'm cross-posted to sci.bio.  Could someone please explain the theory of
>sexual selection to us, try to justify it (I've never believed it,
>despite the evidence), and relate it to common sexual dimorphism like
>height, etc.?

Let me make it simple, and talk about buying apples for a moment.  When
you eat an apple you want one that is ripe, does not have worms in it,
is not spoiled or bruised, and so on.  So what do you do when you go
to buy apples -- you look for one that is red, looks juicy, and is
unblemished.  The vendors of apples want to sell you apples, so they
take due care to provide apples that meet these criteria.

Note that these criteria don't actually tell you that this apple is
going to be good eating.  Note also that the vendor of apples is not
trying to supply you with good eating, she is trying to sell you what
you will buy.  Even so, you will tend to select the really red apple
unless you think about it, and the vendors of apples apply artifice
to make there apples redder than nature intended.  

Now you, as a clever human being, can figure out what the vendor is
up to, and can figure out what it is that you actually want.  But an
animal is not so clever, and relies on built in cues to make these
selections.  Success in breeding goes to those males who best meet
the built in cues.  Now these cues are often things like redness in
apples -- whence, the redder the better.  Males who most markedly
satisfy the selection criteria are most likely to get selected.  This
gets inherited, so the selection process drives steadily towards
emphasizing any feature that is used as a cue.

NOTE THAT IT IS THE FEMALE THAT SELECTS.  Females select, fundamentally,
because they make the big investment in offspring.  Since they do the
selecting, the selection process is not as demanding on them (except
that they must provide reliable fertility cues).

This is the general theory.  Human beings, at this point, are in a
special category; our sexual selection process does not match our
evolution -- we have mixed it all up by having intelligence and
civilization.
-- 

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