Re: Van Valen's MAXIMAND



> > > TT:-
> > > I think smaller, faster-reproducing organisms do pretty well
overall -
> > > but I don't think smaller creatures always beat out larger ones.

> > JE:-
> > This was not my point. Darwinism predicts that forms evolve body
sizes
> > to become _as small as possible_ for any particular species life
style.
> > This is simply because minimising body size frees up more limited
> > resources for other things, i.e. the smallest possible body size is
the
> > most efficient use of limited resources for any Darwinian parent.

> TT:-
> In the light of this heuristic, it is not obvious how the lifestyle
> of "plankton eating vertebrate" resulted in the blue whale.

JE:-
My view that "forms evolve body sizes to become _as small as possible_
for any particular species life style" is not just a heuristic model.
The reasoning is based on the assumption that the enormous range of body
sizes that actually exist between different species when compared to the
much more restricted range in body size within one species must be the
result of adaptation. Species of plankton eaters range from tiny
microscopic forms to enormous whales. As you increase body size volume
increases more and more compared to surface area providing _both_ gains
and losses for each organism size. Van Valen's maximand concept argues
than an increase in body size must provide a fitness gain which is
simply not true.

> > > TT:-
> > > ...and when it comes to fitness, you can put me down as one who
would
> > > rather measure it in terms of biomass than sheer number of
> > > individuals.

> > JE:-
> > The biomass of one gene? One cell? One individual? One fertile
> > individual? One population? One species? The entire earth? The
universe?

> TT:-
> I was mostly thinking about species.

JE:-
Darwinism predicts that biomass must increase over time as a result of a
consistent increase in individual TDF's. I did ask you where the
critical competitive fitness interface exists within your proposed
fitness metric that allowed a comparison of at least two total fitness
(a minimal relative fitness) providing a selective result that can be
measured but you just snipped the question. Are you arguing that the
biomass of one species is competing against the biomass of another such
that the species with the larger biomass is being naturally selected
over the one with less?

> TT:_
> Higher levels would also make
> sense in this context - e.g. when comparing say, Coniferophyta with
> Magnoliophyta, using biomass seems preferable to counting individuals.

JE:-
I cannot see any rational fitness in comparing biomass or total counts
of individuals for different _species_. Perhaps it would help me if you
provided an example of a proposed fitness metric that did _not_ make any
sense and then explain why this was the case.

> > > TT:-
> > > Biomass is not a great metric, perhaps - but at least it doesn't
> > > tend to penalise populations with larger individuals in resource-
> > > limited environments in proportion to individual size.

> > JE:-
> > You firstly have to define what is and what is not an individual
within
> > a population. Your example of a large organism was just a clone,
i.e.
> > you have misused the gene centric _model_ of what a biological
organism
> > is. Clones are not single Darwinian selectees anymore than identical
> > twins are the same Darwinian organism with the same Total Darwinian
> > Fitness within one population.


> TT:-
> I prefer a "pornography"-style definition of organism myself ;-)

JE:-
I don't get the joke. No matter how much anybody dislikes the organism
concept whenever you delete it the science of biology ceases to exist.

> TT:-
> The largest organism is thought to be this one:
> http://www.infoplease.com/spot/fungus1.html

JE:-
I remain sceptical. The organism concept has always been a problem for
the fungi. They can be coenocytic containing the nuclei of several
different parents:
http://www.ilmyco.gen.chicago.il.us/Terms/mycel137.html. Slime moulds
provide an "on the face of it" evidence that individual cells may
represent fungal organisms because the cells that sacrifice themselves
to become the stalk and not the spore which alone passes on genes to the
next generation after cell aggregation do so because of mutualistic and
not altruistic reasons.

> TT:-
> I expect the combination of genetic and bodily continuity were part of
why
> this was classified as one organism, rather than being a collection
> of many individual clones.

JE:-
The organism concept is utterly basic to any science of biology but it
does remain elusive in a few cases. Like any concept the organism
concept only represents an assumption on which to build a refutable
theory.

Regards,

John Edser
Independent Researcher

PO Box 266
Church Pt
NSW 2105
Australia

edser@xxxxxxxxxx












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