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From: throopw@rtp47.UUCP (Wayne Throop)
Newsgroups: net.origins
Subject: No Cigarettes, Please
Message-ID: <112@rtp47.UUCP>
Date: Fri, 26-Jul-85 13:08:55 EDT
Article-I.D.: rtp47.112
Posted: Fri Jul 26 13:08:55 1985
Date-Received: Sun, 28-Jul-85 09:11:18 EDT
References: <1318@uwmacc.UUCP>
Organization: Data General, RTP, NC
Lines: 84

It seems that a lot of the discussion in the referenced posting is based
on a misperception.  In particular:

> So x1 leaves a lot of offspring, but does not survive very well
> itself.  It breeds a lot and then kicks off.  x2 does not leave many
> offspring, but survives much longer.
>
> Which is fitter?

There is the implicit assumption that there is a linear scale of
"fitness".  This is a deeply rooted problem that appears in many
places.  IQ, testing for an ominous example.  Resteraunt grading for
another.  After all, which tastes better, Cajun cooking or German?

I would say then that much of what followed is bogus, since it is based
on the notion that natural selection is based on an absolute fitness
scale.  Natural selection is based more on competition for available
resources.

Some other specific points:

> The error (as it seems to me) is that the link between survival and
> reproduction in assessing fitness is unnecessary, or at least
> poorly-defined or wrong.  It *seems* to me (I may be wrong, so no
> flames - just point out my error) that the two are tied together in a
> way that cannot logically be required:  there is no necessary
> relationship between survival of the "fit" individual (measured by
> lifespan) and generation of the next "fit" population (measured by
> reproductive success).

The relationship seems clear to me.  Most organisms cannot (or likely do
not) reproduce at all until a certain age, and then they reproduce for
at some rate *after* that age.  Therefore an organism must first live
long enough to reproduce at all.  Then, the longer-lived organisms will
produce more total offspring, since number of offspring is the rate of
reproduction times the length of time spent reproducing.  Thus, there is
a simple and direct relationship between lifespan and reproductive
success (where lifespan is (perhaps) one component of fitness).

> By saying that the ones that survive reproduce more (that is what Rich
> said, and what Mike I think defended), one makes this link.  But on
> what basis?  I assume on this basis:  the ones that survive longer,
> leave more offspring *all other things being equal*.  I suppose they
> will - but why make this assumption?  Things are not obviously equal.
> To make the theory work?  Not a chance.  It has to be *shown*, not
> assumed.

Nonsense.  This is just what is done in physical systems, such as
relating temperature, pressure, volume, and so on.  The assumption of
"other things being equal" isn't needed to make the theory work.  It
just makes it clear what happens *if the assumption is so*.

If other things are *not* equal, there will still be *benefit* to being
(say) longer lived.

> But we certainly do NOT have
>
>         drs = f (fitness only)

Quite so.  But longevity (what you seem to be calling fitness here)
*does* bestow relative reproductive advantage.

> [...]
> demonstrate how we may decouple fitness from reproductive ability, for
> that must be done to use differential reproductive success as a valid
> indicator.

No it mustn't.  I'm not at all sure what makes Paul think it must.

> Witness also the great importance attached to natural selection by many
> on this net.  But how important is it in recent evolutionary theory?
> Not very, in a number of instances.  Michael Lonetto has shown evidence
> that he knows this.  How many others?  Rich is (apparently) still in
> the dark ages, carrying this (apparently) *unexamined conviction*
> around.  Mike H might be, but I doubt it; I suspect that he was trying
> to clarify what Rich said, rather than defend it as his own position.

I don't follow this at all.  Perhaps some of the enlightened, such as
Michael Lonetto, would let me in on the secret.  In what way is natural
selection unimportant to "recent" evolutionary theory.

> Paul DuBois     {allegra,ihnp4,seismo}!uwvax!uwmacc!dubois
-- 
Wayne Throop at Data General, RTP, NC
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