Re: Felsenstein and reproductive excess
- From: "John Edser" <edser@xxxxxxxxxx>
- Date: Sat, 4 Jun 2005 02:37:33 -0400 (EDT)
"Walter ReMine" <science@xxxxxxxx>
> > JF:-
> > I cannot claim to know Haldane's intentions, but
> > ISTM that he was trying to come up with a mathematically
> > tractable, but biologically realistic, model which
> > would allow fitness to "increase" over time without
> > population counts (unrealistically) increasing
> > (and accelerating!) to match. That is, he needed
> > some population-limiting assumption to counteract
> > the population-expanding continual increase in "fitness".
> WR:-
> I disagree. Haldane assumed a constant population size: (1) Because he
> (confused) based his cost concept on "genetic death", which fails to
> work when the population size changes. (2) Because constant population
> size is needed in order to obtain closed-form equations for the total
> cost of substitution (which cannot be obtained when the population
size
> arbitrarily fluctuates). (3) Because constant population size is a
fair
> assumption for instructional purposes, and in several other respects
> too.
JE:-
One way a biological population can remain at the same size is when each
parent (fertile form) always manages to replace itself and no more,
without fail. This can be done in either a high or low fecund
(reproduction of sterile immatures) way. If you reproduce 10,000
immatures but only one survives to fertile adulthood this is not the
same biological event as reproducing just one immature that you always
successfully raise to fertile adulthood. In the high fecund case you
have 9,999 other acts of sub selection to more painlessly pay the cost
of substitution. Sub selection is a dependent act of selection, i.e. the
level at which selection is acting (the infertile immature level of
selection) is entirely dependent on the level above (the Darwinian
fertile form level) allowing sub selection to be much less costly than
selection. It costs much less to reproduce infertile immatures than it
does to reproduce fertile adults! Because Neo Darwinistic models allow
sterile immatures to become fitness equivalent to fertile adults they
simply delete the process of sub selection which can more cheaply pay
the cost of substitution.
All results of oversimplified models are supposed to be corrected by the
theory they oversimplified from BEFORE these results are employed within
any scientific context. Obviously, in Haldane's case this was never done
allowing his false dilemma to incorrectly become a biological dogma.
> > JF:-:
> > The question that Haldane sought to address is
> > difficult to handle under the usual methods of
> > population genetics. Pop gen, when it computes the
> > increase in the fitness of a population (i.e. the
> > increase in the average of the fitnesses of
> > individuals) does not usually project the consequences
> > of this increase forward over evolutionary or
> > geological time.
> > ....
> > A mutation could increase K and reduce r at the same time.
> WR:-
> That is confusion. The central issue in Haldane's Dilemma is not
> fitness, but rather the GROWTH RATE (or increase in number of copies)
> of new alleles, and the reproduction rate required to produce it.
JE:-
Finally, Felsenstein is preparing to bite the FITNESS bullet. ReMine is
incorrect. FITNESS IS REPRODUCTION within any SCIENCE of biology.
However, it is not the reproduction of just anything at all it is very
strictly, the total reproduction of fertile forms into one population by
each parent, i.e. Total Darwinian Fitness (TDF). This is the only
empirical definition of fitness that exists within the science of
biology. Fitness remains the central issue of all of the biological
sciences and this includes Haldane's false dilemma because it is the
only common currency that evolutionary theory has. The reason as to why
the dilemma was always false is because Haldane got the critical fitness
concept wrong. Sadly, it remains incorrect to this very day.
> WR:-
> Whether or not the average fitness goes up, down, or remains the same
> is largely irrelevant to that requirement. Whether or not the new
> allele alters K or r is largely irrelevant to that requirement. If an
> allele is claimed to increase (in number of copies) by, say,
> twenty-five percent in one generation, then a reproduction rate of at
> least 1.25 is required. Period. The environment, fitness, soft
> selection, and factors K and r, do not reduce that figure one iota.
> Felsenstein is wrong to insist otherwise.
JE:-
For the population to remain the same size the average Total Darwinian
Fitness (TDF) has to remain the same.
Once again ReMine correctly insists that an absolute cost of
substitution has to be paid where it does form a ceiling for the maximal
rate of substitution but ReMine flatly refuses to acknowledge that ALL
biological costs constitute an investment for a fitness INCREASE
allowing a RELATIVE cost of substitution to become zero. OTOH
Felsenstein only allows the relative zero cost and flatly refuses to
acknowledge that the absolute cost of substitution has to be paid where
that cost does form a ceiling for the rate of substitution. Felsenstein
and ReMine are still mindlessly shouting past each other. However,
Felsenstein is well paid to know better...
John Edser
Independent Researcher
PO Box 266
Church Pt
NSW 2105
Australia
edser@xxxxxxxxxx
.
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