Re: Survival of the Fittest

Dave Rindos (arkeo4@UNIWA.UWA.EDU.AU)
Wed, 13 Sep 1995 17:18:38 +0800

On Wed, 13 Sep 1995, Iain Davidson wrote that somebody (not Iaia, and I'm
afraid I didn't keep the original) wrote:

> >1 re definition of "fitness". You cannot even measure it with the
> >athletes, i.e. who is fitter a marathon runner who in the gym cannot lift
> >up (even with their legs) a lightest weight, a bodybuilder who has
> >stamina to lift up heavy weights and lifts really heavy and a lot, or a
> >person who does not run a marathon, but is fit to do some things and who
> >lifts weights (quite well) but is miles away from a bodybuilder?
> Of course what you say is true, and fitness is not a word I use very much
> (personally or professionally), but that is the word that started the
> thread. What I was concerned about was trying to get beyond the social
> Darwinist position to see if anything like this could be applied, and
> my ONLY point for this list is that there must be a time dimension to the
> evolutionary concept.

OK, I couldn't stay away anymore -- "fitness" as used above has NOTHING
WHATSOEVER with the word 'fitness' in evolutionary theory.

Nothing. Nada. Zip. 0.

The ongoing discussion of fitness in biology is complex and intricate,
(I recommend Elliot Sober's NATURE OF SELECTION as a starting point, or
for something more simple-minded, even my own work on the topic).

Basically, fitness refers to a case where the presence of a HERITABLE
trait is corollated with a differential increase, [as Iain notes] over
time, in the proportion of individuals having that trait in the larger
population under consideration.

Not nearly as simple as running the four minute mile, or whatever, I'm
afraid. But that's life . . .

Fitness is a (theoretically) observable thingie. But, IMPORTANTLY,
knowing that a trait may confer fitness (in a given population at a given
time and in a specific environment) does NOT tell us WHY fitness has been

Oftentimes, the word "adaptation" may be used to explain why a trait has
lead to increased fitness; but this also gets VERY complex. Another huge
literature, again with considerable controversy (within the broad limits
of even greater agreement on the basic outlines).

For the purposes at hand, we may observe that increased fitness may occur,
not by increased ADAPTATION in the sub-population with the trait, but
rather because the trait at hand tends to DECREASE the adaptiveness of the
carriers of other traits. At that point, fitness is pretty close to
postmodernist notions of power.

But I begin to digress... the important thing to remember is that ALL
species have gone extinct whilst maximizing their fitness at each step
along the way. Yes, Dorothy, species can evolve themselves into
extinction. Happens all the time....

maybe even watching it happen in a little-bitty way....