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From: keithd@cadovax.UUCP (Keith Doyle)
Newsgroups: net.origins
Subject: Re: No Cigarettes, Please
Message-ID: <724@cadovax.UUCP>
Date: Mon, 29-Jul-85 23:05:32 EDT
Article-I.D.: cadovax.724
Posted: Mon Jul 29 23:05:32 1985
Date-Received: Sat, 3-Aug-85 02:15:42 EDT
References: <1318@uwmacc.UUCP>
Organization: Contel Cado, Torrance, CA
Lines: 139

.........
>Of course, my own personal choice of x2 is questionable; it depends
>what level you look at.  At the level of the group, x1 is fitter; it
>propagates more.  At the level of the individual, x2 is fitter; it
>survives longer.

It's even more complicated than that.  In an environment where it is
most important to reproduce, then x1 is better, where it is not so
important (maybe overpopulation causes most of them to die anyway)
then they may be on equal terms or even x2 could have the advantage
(perhaps an animal being pregnant might be more succeptible to 
predation for various reasons).

>empirically.  Here I throw up my hands and "resolve" the paradox by
>deciding that the criterion of fitness is worthless.  (I put "resolve"

The criterion of fitness is not absolute, but relative
(to the complex details of the individual environment).
You seem to want to pigeonhole the criteriae for fitness
in some sort of absolute value system.

>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.  In my example, it's false.  Its not a thing to be considered

We cannot assume it is false without more details.  Under some circumstances
x1 is fitter, under others x2.  There is no all pervasive criteria for
judging the fitness of x1 and x1.

>like, "the ones that live for a shorter time will be selected for
>maximum reproductive rate, and thus will be at no disadvantage."  Well,
>sure.  But so will the ones that live longer.  If we take that route,
>the criterion, reproduction, is what gets selected for, not something
>else.  We end up with a view of organisms that are adapted *to
>reproduce*.  But that was the way they *expressed* their fitness, I

Effectively, that is what we have.  However, an immense variety of 
characteristics and conditions can interplay to make up relative
fitness for reproduction.  In addition, various characteristics may
be intertwined with characteristics that have very little to do with
reproduction, thus causing them to be 'carried along' with the more
important selection characteristics.  The basic ability to survive is
intertwined with the ability to reproduce.  The ability to feed oneself
and avoid predation is intertwined with the ability to survive.  The 
ability to keep from freezing in cold climates may be intertwined if
an organism lives in the cold etc.

>Those which are fitter will leave more offspring
>	but only true if fit *to leave offspring*
>	or, if fitness *is defined as* leaving more offspring
>
>and then "fitness" is meaningless, because it says nothing.  Try it -
>make the substitution of variables:
>
>	fitness = fit to leave offspring, yields
>    Those which are fit to leave more offspring will leave more offspring
>
>	fitness = leaving more offspring, yields
>    Those which leave more offspring will leave more offspring
>
>Not very illuminating.  Hence my frequent comments in the past about
>vacuity.

I would say that it in itself is awfully obvious.  Apparently it's
entertwinement with evolutionary theory is where it becomes confusing
(thus the apparent repeated confusion on N.S. and relateds in this
discussion).

>Is an increased number of offspring a necessary consequence of
>fitness?  I don't think so.

Is it a necessary consequence of survival?  Not necessarily, as before,
the number of offspring may have nothing to do with reproductive success.
An organism that only has one offspring but can protect it from predation
better than another organism that has umpteen offspring, may achieve higher
reproductive success.

>At the very least, our covert variable, fitness, is confounded with
>something else, i.e., reproductive *ability*.  Differential
>reproductive success is in part or whole a function of reproductive
>ability.  I do not think this can be disputed.  It may also be, and
>probably is, a function of other factors, among which fitness may well
>number.  That is,
>
>	drs = f (reproductive ability, fitness?, ... )
>
>But we certainly do NOT have
>
>	drs = f (fitness only)

Here I would almost agree.  I would say that drs is equivalent to f, but
that;

        drs = f = (reproductive ability, longevity, fertileness, ability
                   to cope with present environmental concerns, ability to
                   avoid predation,.........)

Only because I define fitness as drs.  Your definition of fitness seems
to be some personal subjective judgement.  You have to ask, fitness
for what?  I would respond, to reproduce.  Perhaps you have a different answer
here.

>If anyone thinks that the latter is true, then I invite you to
>demonstrate how we may decouple fitness from reproductive ability, for
>that must be done to use differential reproductive success as a valid
>indicator.

Valid indicator of what?  DRS is a mechanism for filtering out
harmful (to DRS) mutations, and preserving useful ones.  Sure, DRS=F
dosen't say much, it's ridiculously obvious.  It's effect as a filter
and as an adaptation mechanism is where it all gets interesting.

>But if fitness is defined some other way, e.g., ability to live longer,
>then there is no necessary link with reproductive capacity.  And then,
>I think, the whole thing falls apart.

No, the bottom line is, the ability to produce offspring that survive.
Its just that:

      DRS <> (quantity of offspring)
or
      DRS <> (longevity)
or
      etc....

because there are all kinds of other factors.  In addition, characteristics
that are neutral with regard to DRS, are not necessarily filtered out in 
the process, though they may later resurface and become non-neutral if other
considerations (environment, related characteristics, etc.) change.

>Paul DuBois     {allegra,ihnp4,seismo}!uwvax!uwmacc!dubois        --+--

Keith Doyle
#  {ucbvax,ihnp4,decvax}!trwrb!cadovax!keithd