Text 871, 226 rader
Skriven 2004-11-19 06:15:00 av John Edser (1:278/230)
Ärende: Re: The "fuel" of evoluti
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phillip smith <deletethis-phills@ihug.co.nz> wrote:-
> > JM:-
> > We all know that heritable variation in characters affecting fitness
> > is a prerequisite for natural selection. Metaphorically speaking,
> > we can even say that heritable variation is the "driving force"
> > for NS.
> > This is a good metaphor because variation plays a force-like role.
> > Assuming you quantify "variation" as the variance in fitness, the
> > infamous "Fisher's Fundamental Theorem" assures us that the
> > magnitude of the response is proportional to the magnitude of the
> > "force". Furthermore - (correct me if I am wrong here!) -
> PS:-
> I think you may be in error here. Standard darwinism is not directed by
> variation, assuming variation is every direction. Heritable variation in
> characters does not force evolution. The rate of evolution is proportional
> to variation. The force is the strength of selection. You could have very
> high variation and no change at all in under intense stabilising
> selection.
JE:-
Hi Jim welcome back. I missed your
"honest broker", approach.
Here I agree with Phillip, especially if you
define variation as being produced by
by just a random process. Quite obviously,
even if entire genes can be deleted by it
e.g. genetic drift which is a random process.
Any random process cannot direct anything.
That is the reason it is termed a random
process. A random pattern cannot direct
anything either but a random pattern
(not a random process) may be caused
by either a random or non random
process. So any non random process that
produces a random pattern may direct things
but not via any random pattern it produces.
An example would be meiosis. Until meiotic
drive genes were discovered it was assumed
that meiosis was just a random process.
The t allele of mice is an example. Once
discovered it was shown that these genes
did fit Hamilton's expectations, i.e.
Hamilton's rule was verified by the t allele.
Of course verification and non verification
are *NOT* definitive. In just relative_
(comparative) measure only, the t allele can
increase compared to the wildtype gene
at however at an absolute cost to both
because this gene causes one adult form
to become sterile. Quite obviously t
alleles can only constitute a tiny part
of a population or they extinguish a
population.
The fact of a relative gain only obtained
at an absolute cost should have been seen
to be of much greater significance than
just the relative increase of the t allele.
Typically, this fact was just ignored
because the total fitness of the actor
is simply deleted from Hamilton's Rule
just at it was deleted from Haldane's
comment in a pub by which Hamilton
was pre-empted. As far as Darwinism
is concerned, the t allele was not
selected for, it just arose via random
variation. At the moment only negative
meiotic drive effects have been documented.
I think this is because they are more obvious.
I propose that if a beneficial gene was
so driven then the rate of evolution could
be accelerated. The cost would
be the occasional pushing of the wrong genes.
I argue that meiotic drive was selected
for because it provided a mean increase in total
Darwinian fitness even if it can occasionally
be non beneficial, i.e. it follows the logic
of mutation except that meiotic drive is
non random. Mutation protection
and repair are not random. The struggle is to
balance variation with selection to provide
the best outcome within changing environments.
This is what Darwin proposed. Nothing has
changed since then. People are not even
reinventing the wheel, they are just dragging
carts without wheels arguing these are more
modern.
If variation is not just a random process
then it could direct evolution. In this
instance it would have to compete against
natural selection if these two non random
processes contested in their direction.
It is just obvious that selection will win.
This is why Darwin's idea was so enormous.
Selection cannot be beaten. This has miffed
so many people it is not funny..
> PS:-
> However Kimura and Ohta had other ideas. If you take evolution as
> the change
> in gene frequecies then the rate of evolution is a function of
> the mutation
> rate ie variation if accept the neutral theory. It is a bit like diffusion
> vs mass flow.
JE:-
Defining evolution as just ANY change
in gene frequencies is like defining
wealth as ANY increase in money. Both
are hopelessly incorrect. REAL
wealth increases may or may not be correlated
with increases in money, e.g. hyper-inflation.
Allowing random changes in gene freq. to validly
constitute evolution and not just variation is
just an evolutionary theory act of fitness
hyper-inflation.
> > JM:-
> > the
> > direction of the response matches the direction of the "force".
> > If the total variance in fitness is divided among several
> > characters, the characters that evolve fastest are those that make
> > the largest contribution to the fitness variance.
> >nip<
> > Of course, the true value of a metaphor lies in the follow-up
> > questions that it suggests. Is there a difference in the fuel
> > efficiency of various evolutionary situations? Does the combustion
> > require two different fuel components (oxidizer and reductant)
> > with either component potentially limiting? Etc.
> PS:-
> I think a trap you may be falling into here is believing that fitness is a
> real property of individuals. Fitness can only be ascribed to alleles. We
> can measure the frequency of an allele at time x and x +1 and see a change
> frequencies and try and determine the probability the change happening by
> chance. If chance seems unlikely then maybe it was selection.
JE:-
This is where I disagree with Phillip.
Fitness is a REAL and EXACT measure of Darwinian
fertile organism selectees. I have defined it and
provided an experiment that can refute it. Such
basics have NOT been completed by Neo Darwinians
who seem to comprise of a rag tag collection of
mathematicians who know almost nothing of the
science of biology. They cannot provide a theory
of fitness that can be tested to refutation so
what do they do? They just throw the process
of refutation out the window and claim irrefutable
axioms of mathematics are enough. Let me assure
reader's mathematics is NOT a science. Dispensing
with Popper is the same logic as killing the patient
to cure a disease.
The problem with Darwinian fitness is the
fact that it is gene _fitness_ epistatic.
Neo Darwinism simply tackles this problem
like it tackled Popper, just delete it.
All these deletions are fine within simplified
models because models are NOT theories
of nature they are just theory approximations
used to help to understand the theory they
were simplified from. Like some sort of
Neo Darwinian Dracula these models have taken
on a life of their own which they do NOT
posses and are used to invalidly contest
and win against their own parent theory.
Such an act is absurd.
> PS:-
> Fitness is a very slippery concept and I personally feel it has been badly
> formulated. I am working on an alternative formulation that I feel is
> superior but requires a rethink of population genetics.
> Unfortunately I need
> to publish first in scientific journals for all the reasons that have been
> recently discussed so I can not reveal it to sbe. This has been
> the fruit of
> some ten years work. I need to finish the phd I should have finished eight
> years ago. I have recently returned to a lab part time about 8
> hours a week
> when I am not working. So I hope to finish this soon. I look forward to
> presenting my ideas to sbe at the appropriate time.
JE:-
Phillip, you are only attempting to reinvent the
wheel. Darwin (implicitly) defined fitness as
the total number of fertile forms reproduced
into one population by one parent. Epistatic
gene fitness is _totally_ fertile organism centric
and not at all gene centric. In order to provide
a REAL gene level of selection gene fitness must NOT
be epistatic, i.e. all gene fitnesses must be
additive and not non additive. The Darwinian
total fitness concept is the only fitness
concept that can be tested to refutation.
Unless a theory of fitness can be tested to
refutation and not just non verification,
it cannot validly compete against the
Darwinian refutable concept.
My Regards,
John Edser
Independent Researcher
PO Box 266
Church Pt
NSW 2105
Australia
edser@tpg.com.au
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