> Guy Hoelzer  wrote:
> I have a simple suggestion about the validities of considering
> absolute vs.
> relative fitnesses.  IMHO, focusing on absolute fitnesses is ideal in the
> absence of dynamical feedback among individuals (more generally,
> elements of
> your dynamical system).

JE;-
In my view Darwinian absolute fitness remains
essential for differentiating between dependent
and independent fitness associations. Clearly,
being able to differentiate between them is
extremely significant to any selective event
and thus to any rational evolutionary theory.


> GH:-
> On the other hand, feedback is often generated
> through social and ecological interactions such as competition.  I have
> often argued in favor of using relative fitness because I am comfortable
> assuming that growing populations will always run into resource limitation
> leading to within population competition, which elevates the importance of
> relative fitness compared with absolute fitness.

JE:-
I do not agree that "resource limitation leading to
within population competition" "elevates the importance of
relative fitness compared with absolute fitness". I argue
exactly the opposite is the case. This is because only
an increase in absolute fitness forces an absolute
increase in available resources. It is mostly a
myth to argue that available biological resources
are absolutely fixed. Most biological systems can
only utilise a tiny fraction of their available
resources. Resource limitation is mostly a case of
recourse utilisation.

> GH:-
> JE can correctly argue
> that fitness interactions, such as competition, can manifest evolutionary
> effects by changing absolute fitness tallies, but I don't find
> that argument
> to be a persuasive reason to stick with an absolute fitness model.

JE:-
If total fitness tallies are not being compared
what are?

I am not arguing that a Darwinian absolute fitness
measure should replace a relative fitness measure or
vice versa, I am simply arguing that each has its place
in logic where both are always required. Attempting to
reverse their logical relationship or delete either
of them within any science of biology is absurd.


> GH:-
> A fundamental difference between the two approaches is that the relative
> fitness approach anticipates and integrates the effects of factors that
> limit population size (e.g., competition).

JE:-
Yes, relative fitness _limits_ population size but it
does not _determine_ population size because only absolute
fitness can do that. Just as a racing car driver is limited
by the car he/she drives, the driver races the car, the car
does not race the driver. Causation is limited by what
is available but is not determined by it. Selective
causation can be absurdly reversed within the
biological sciences. The cause of selection is not
what limits it: relative fitness (the car) it is
what drives it: absolute fitness (the driver).
This is why absolute fitness cannot be _selected_
to be _reduced_. However, organism fitness altruism
(OFA) in nature can only be  measured when the
absolute fitness of the actor _is_ selected
to be reduced. Hamilton had to reverse cause an
effect to allow OFA but did not provide any
valid reason to be able to do so. He provided
no general term within his rule to represent
the absolute fitness of the actor so nobody can measure
when the actors absolute fitness had been reduced. The
testable theory remained entirely Darwin's and NOT
Hamilton's.

> GH:-
> The absolute fitness approach
> assumes that population sizes are not constrained, or that we can safely
> ignore any effects of population regulation.

JE:-
This is not true for Darwinian absolute fitness.

>snip<

Regards,

John Edser
Independent Researcher

PO Box 266
Church Pt
NSW 2105
Australia

edser{at}tpg.com.au
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