Re: Nei's "new mutation theory" resurrects William Bateson
- From: Arlin <arlin.stoltzfus@xxxxxxxxx>
- Date: Wed, 19 Dec 2007 13:53:04 -0500 (EST)
On Dec 18, 12:56 pm, d...@xxxxxxxxxxxxxxxxxxxxxxxxx (DK) wrote:
An appeal to authority in place of the valid argument.
Which is surprising because 1) Behe's position is impossibly weak
and can be dealt with properly, 2) Dawkins knows and can do much
better (but apparently can't resist cheap shots).
Cheap shots, indeed. I directed you to the documentary evidence in
Stoltzfus (2006) which you did not read. I will provide some
quotations from the MS architects below. Unfortunately, your
statement above reflects an unwillingness to accept evidence-- Dawkins
says "X" but you interpret this to mean "not X" on the grounds, that
in spite of what he *actually wrote*, you are confident that he "knows
better".
Of course the rate of evolution depends on the rate of mutations!
Had anyone seriously suggested that it's not?
Yes, they have, and that's exactly the point that I am making, and
that Dawkins was making. I only quoted Dawkins because he faithfully
reflects the MS position documented in statements such as the
following:
"The large number of variants arising in each generation by mutation
represents only a small fraction of the total amount of genetic
variability present in natural populations.... It follows that rates
of evolution are not likely to be closely correlated with rates of
mutation. Besides mutation, natural selection and migration help
maintain high levels of genetic variation in natural populations. Even
if mutation rates would increase by a factor of 10, newly induced
mutations would represent only a very small fraction of the variation
present at any one time in populations of outcrossing, sexually
reproducing organisms." (Dobzhansky T, Ayala FJ, Stebbins GL,
Valentine JW: Evolution: W.H. Freeman, 1977, p. 72)
"mutations are rarely if ever the direct source of variation upon
which evolutionary change is based. Instead, they replenish the supply
of variability in the gene pool which is constantly being reduced by
selective elimination of unfavorable variants. Because in any one
generation the amount of variation contributed to a population by
mutation is tiny compared to that brought about by recombination of
pre-existing genetic differences, even a doubling or trebling of the
mutation rate will have very little effect upon the amount of genetic
variability available to the action of natural selection.
Consequently, we should not expect to find any relationship between
rate of mutation and rate of evolution. There is no evidence that such
a relationship exists." (Stebbins, Processes of Organic Evolution.
Englewood Cliffs, NJ: Prentice Hall; 1966., p. 29)
"Those authors who thought that mutations alone supplied the
variability on which selection can act, often called natural selection
a chance theory. They said that evolution had to wait for the lucky
accident of a favorable mutation before natural selection could become
active. This is now known to be completely wrong. Recombination
provides in every generation abundant variation on which the selection
of the relatively better adapted members of a population can
work." (Mayr, The Resistance to Darwinism and the Misconceptions on
which it was Based. In: Creative Evolution? Edited by Campbell JH,
Schopf JW. London: Jones & Bartlett, Inc.; 1994, p. 38)
"The process of mutation supplies the raw materials of evolution, but
the tempo of
evolution is determined at the populational levels, by natural
selection in conjunction
with the ecology and the reproductive biology of the group of
organisms" (Dobzhansky,
1955, Evolution, Genetics and Man. New York: Wiley & Sons, Inc, p.
282)
"It is most important to clear up first some misconceptions still held
by a few, not
familiar with modern genetics: (1) Evolution is not primarily a
genetic event. Mutation
merely supplies the gene pool with genetic variation; it is selection
that induces
evolutionary change." (Mayr, Animal Species and Evolution. Cambridge,
Massachusetts: Harvard University Press, 1963, p. 613)
"Each unitary random variation [mutation] is therefore of little
consequence, and may be compared to random movements of molecules
within a gas or liquid. Directional movements of air or water can be
produced only by forces that act at a much broader level than the
movements of individual molecules, e.g., differences in air pressure,
which produce wind, or differences in slope, which produce stream
currents. In an analogous fashion, the directional force of evolution,
natural selection, acts on the basis of conditions existing at the
broad level of the environment as it affects populations." (Dobzhansky
T, Ayala FJ, Stebbins GL, Valentine JW: Evolution: W.H. Freeman, 1977,
p. 6)
"Novelty does not arise because of unique mutations or other genetic
changes that appear spontaneously and randomly in populations,
regardless of their environment. Selection pressure for it is
generated by the appearance of novel challenges presented by the
environment and by the ability of certain populations to meet such
challenges."(Stebbins, Darwin to DNA, Molecules to Humanity. San
Francisco: W.H. Freeman and Company, 1982, p. 160)
Thus, precisely as I explained before, in the MS the "gene pool"
serves as a "buffer" that insulates "evolution" (=shifting gene
frequencies) from any influence of mutation that might result in a
rate-dependence or in a directional influence of mutation biases. The
MS architects spilled much ink on elaborate hand-waving arguments for
why the "gene pool" would have this effect, but in the end, these
arguments come to nothing, because the conclusion is wrong.
Arlin
.
- Prev by Date: Re: Article: Group selection, a theory whose time has
- Next by Date: Re: James Watson and the Monkey Test
- Previous by thread: Re: Nei's "new mutation theory" resurrects William Bateson
- Next by thread: Re: Nei's "new mutation theory" resurrects William Bateson
- Index(es):
Relevant Pages
|
