Re: Dawkins gives incorrect answer
From: Michael Ragland (ragland37_at_webtv.net)
Date: 08/19/04
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Date: Thu, 19 Aug 2004 23:35:53 +0000 (UTC)
Michael,
in article cfvpma$2kv2$1@darwin.ediacara.org, Michael Ragland at
ragland37@webtv.net wrote on 8/18/04 7:39 AM:
It's too bad Mr. Hoelzer read the other responses in this thread but
chose not to respond to them. Instead, he digested the whole meal.
GH:
I think there is a role for such posts.
MR:
With a subject this complex and important I don't think so but you've
responded to me so I grant you some leeway. In any event, posters are
free to respond as they wish.
MR:
To his comments I would state that "yes" mutations add information to
the genome. However, it was my point (perhaps erroneous) that according
to Shannon's information model mutations represented the prior unknown
or that wider field of possibilities which natural selection tailored
down to probable possibilities and finally that which helped the
organism survive and reproduce. However, it was my point (perhaps
erroneous) that according to Shannon's information model mutations
represented the prior unknown or that wider field of possibilities which
natural selection tailored down to probable possibilities and finally
that which helped the organism survive and reproduce.
GH:
I think I agree, but I find this sentence hard to parse.
MR:
Just trying to be concise.
MR:
Another important point which Mr. Hoelzer neglected to mention was that
natural selection feeds information into gene pools.
GH:
Actually, I think that I explicitly disagreed with this view. My view is
that natural selection mainly filters out dissonant information. I will
add that it is inheritance (not NS) that "feeds information into gene
pools."
MR:
Let me explain my position. Natural selection not only filters out
dissonant information but it selects mutations which are favorable to
species being able to survive and reproduce.
I already stated, "However, it was my point (perhaps erroneous) that
according to Shannon's information model mutations represented the prior
unknown or that wider field of possibilities which natural selection
tailored down to probable possibilities and finally that which helped
the organism survive and reproduce." You stated you basically agreed
with my parse commentary. You wrote, "I would also agree with Tim that
the typically strong effect of natural selection in decreasing genetic
variation limits the extent of information that can be structurally
configured in the gene pool." I responded, "Yes but it also favors
those qualities which have been selected by natural selection for
organisms to optimally survive and reproduce." You declare, "I've said
as much myself on sbe, and I don't see how this contradicts anything I
wrote." Mr. Hoelzer if natural selection favors qualities which have
been naturally selected for organisms to optimally survive and reproduce
then this information isn't going to just sit stagnant in gene pools but
being genetically transmitted across generations. In other words one of
the functions of natural selection is to add information to gene pools.
Is this exactly the same as inheritance. No, its not. The point,
however, is natural selection and inheritance are interrelated and
qualities which have been naturally selected for organisms to optimally
survive and reproduce are going to be genetically transmitted across
generations. Let me give an example. In our evolutionary past aggression
was selected by natural selection and imprinted on our DNA and it was
necessary for survival and reproduction. Irrespective of inheritance,
genetic variation, etc. every human being born possesses this trait of
aggression. It was naturally selected and through inheritance this
genetic information has been transmitted generation after generation
after generation irrespective of geography, language, etc.
MR:
As I commented to Mr. Tyler mutations are not like rain showers and
human DNA has basically remained the same as it was ten thousand years
ago.
GH:
Evidence? I suspect that this is a guess on your part, and that experts
would either agree or disagree based upon their sensitivity to degree of
divergence. Some, maybe you, would say that a 1% sequence divergence
between the old and extant population can be described as "basically
remained the same." Of course, some instances of the difference between
species involves less divergence than this. Consider the recent
literature on "speciation genes."
MR:
It isn't a guess as what I read what someone else had said. Here's a
brief article showing the similarity of Cro-Magnon mtDNA to modern DNA.
Interestingly, the similariries and differrences between ancient and
modern human DNA are tied up with the arguments from the "out-of-Africa"
school and the multi-regional school of our origins.
Stone Age Genetics: Ancient DNA enters humanity's heritage
Bruce Bower
Genetic material that Italian researchers extracted from the bones of
European Stone Age Homo sapiens, sometimes called Cro-Magnons, bolsters
the theory that people evolved independently of Neandertals, the team
proposes.
GENETIC FACE-OFF. Mitochondrial DNA from this Cro-Magnon (left) and one
other differs markedly from that of Neandertals (right).
S. Ricci
Fossils of two anatomically modern H. sapiens found in a southern
Italian cave yielded mitochondrial DNA, which is inherited from the
mother, say Giorgio Bertorelle of the University of Ferrara in Italy and
his colleagues. The DNA contains chemical sequences that resemble those
of people today but differ substantially from those previously isolated
from four Neandertal specimens, the scientists report.
One of the Italian Cro-Magnons dates to 25,000 years ago; the other to
23,000 years ago. Neandertal fossils that have yielded mitochondrial DNA
range from about 29,000 to 42,000 years old (SN: 4/1/00, p. 213:
http://www.sciencenews.org/20000401/fob2.asp).
"These results are at odds with the view [that] Neandertals were
genetically related with the anatomically modern ancestors of current
Europeans or contributed to the present-day human gene pool,"
Bertorelle's group concludes.
Contamination of ancient DNA can occur easily. However, the
mitochondrial DNA obtained from the Cro-Magnon bones exhibits no trace
of genetic material from other animals unearthed in the Italian cave or
from people who have handled the bones, the scientists assert in the May
27 Proceedings of the National Academy of Sciences.
The researchers compared Cro-Magnon genetic sequences from an especially
variable stretch of mitochondrial DNA with corresponding sequences from
Neandertal fossils and from 80 people now living in Europe or western
Asia.
Cro-Magnon sequences fall within a genetic category shared by people
today but not by Neandertals, the scientists report. This result aligns
with the theory that modern H. sapiens originated in Africa around
150,000 years ago and then replaced Neandertals in Europe rather than
interbred with them, Bertorelle and his coworkers say.
Mark Stoneking of the Max Planck Institute for Evolutionary Anthropology
in Leipzig, Germany, an advocate of this single-origin model of human
evolution, nonetheless regards the new evidence with caution. He hasn't
seen the report but worries that the Cro-Magnon DNA is contaminated.
However, mitochondrial DNA analyses of living people align with the
single-origin, or out-of-Africa, scenario, Stoneking says.
Adherents of the contrasting
multiregional-origin theory of evolution view the Cro-Magnon findings
even more skeptically. They argue that anatomically variable H. sapiens
in Europe, Africa, and Asia interbred enough over the past 1 million
years or more to evolve as a single species.
The reported genetic differences between Cro-Magnons and Neandertals may
be consistent with interbreeding of small Neandertal and large H.
sapiens populations, comments John H. Relethford of the State University
of New York at Oneonta.
Moreover, if mitochondrial-DNA alterations spread quickly by providing
survival advantages instead of gradually by chance, as is usually
assumed (SN: 2/6/99, p. 88:
http://www.sciencenews.org/sn_arc99/2_6_99/bob1.htm), then such evidence
can't be used to reconstruct ancient human evolution, he notes.
Statistical analyses of worldwide living populations' nuclear DNA—the
DNA that holds most of a person's genes—indicate that interbreeding of
H. sapiens and other Stone Age Asian or European groups, if not
Neandertals, contributed to modern humanity's evolution, remarks Alan R.
Templeton of Washington University in St. Louis.
MR:
This is true despite current existing genetic variation which has
included some random mutations. Therefore, natural selection is
certainly a transmission of genetic information across generations.
GH:
This is a very unorthodox view of what natural selection is. Again, the
term used in biology that refers to "transmission of genetic information
across generations" is "inheritance", which is hardly a synonym for the
process of natural selection.
MR:
I understand that. Everything you read in a book doesn't mean it
couldn't be supplemented or enhanced or at least at a more holistic
level incorporated with other biological ideas. I understand when one
reads the patterns of inheritance by Mendel natural selection isn't
going to come up. However, humans are more complex than Mendel's peas
and flowers and our patterns of inheritance involve the genetic
transmission of naturally selected traits.
MR:
I also commented on the redundancy of this information despite existing
genetic variation. I also pointed out that what was naturally selected
in our ancestral environment may no longer be evolutionarily adaptive
today and this can lead a species to extinction. So mutations may indeed
add information to the genome but if those mutations don't occur soon
enough in a *nonadaptive* species then extinction may result.
GH:
OK, but I don't see the relevance of these points to the validity of
Dawkins' claims.
MR:
They don't. I'm just doing my shpiel. I think it is common to think
natural selection selects traits which will ALWAYS be favorable to
surviving and reproducing. That is not necessarily the case.
MR:
Almost everybody on this newsgroup has conceded Darwinian evolution
takes hundreds of thousands of years to effect changes.
GH:
I would be shocked if this were true.
MR:
You would? Why's that? I'm referring to Homo Sapiens here. From what
I've read Darwinian evolution does take hundreds of thousands of years
to effect evolutionary changes and in the case of "major" changes
longer. How have Homo Sapiens signifigantly biologically changed in the
last ten thousand years? I await your answer.
MR:
Natural selection doesn't add information to gene pools but it is the
main mode for transmitting information to gene pools.
GH:
I can agree with the statement that the process of natural selection
transmits information from the environment to the gene pool, but not
that it transmits information from one generation of organisms to the
next.
MR:
You agree the process of natural selection transmits information from
the environment to the gene pool but doesn't transmit that information
from one generation of organisms to the next. I'm puzzled. Do you think
that information transmitted from the environment to the gene pool by
natural selection just sits stagnant in the gene pool? That's impossible
for sexually reproducing organisms.
MR:
Mr. Hoelzer writes, "I would also agree with Tim that the typically
strong effect of natural selection in decreasing genetic variation
limits the extent of information that can be structurally configured in
the gene pool." Yes but it also favors those qualities which have been
selected by natural selection for organisms to optimally survive and
reproduce.
I've said as much myself on sbe, and I don't see how this contradicts
anything I wrote.
C'mon man, wake up! Did you wake up on the wrong side of bed this
morning?
GH:
I might ask you the same thing. I can't see anything in what I wrote
that would have lit your fire to this extent. In fact, I though that my
post expressed a rational middle ground we could all agree on. I can't
even tell from your post what I said that you disagree with. You have
been saying "Yes, but" and the I neglected to say something. Did I
actually say anything that was incorrect, or is it just my perspective
that you object to?
MR:
No, I truly believe you are stating something that is incorrect and that
is that you agree the process of natural selection transmits information
from the environment to the gene pool but doesn't transmit that
information from one generation of organisms to the next. Do you think
that information transmitted from the environment to the gene pool by
natural selection just sits stagnant in the gene pool? That's impossible
for sexually reproducing organisms.
MR:
Mr. Hoelzer writes, "IMHO the interpreter-view of information assumed by
Dawkins and most participants in this thread frequently leads to
fruitless debates because there is no way to find agreement on the state
of the interpreter. We do better, however, agreeing on the data. I think
that we can agree on objective measures of variation and configurational
topologies, which is why I personally prefer the objective information
paradigm. Then you state, "there is value in a theory of signal
detection and data interpretation, IMHO it should be clearly
distinguished from theories of objective information content. In the
latter view, information exists in the absence of observers, and is
limited firstly by existing variation.
How can you agree on "objective measures of variation and
configurational topologies" in the absence of observers? Have you taken
up the David Copperfield School of Evolution?
GH:
The purpose of having objective measures in science is to force
agreement on the data. If my scale says that something weighs 2 grams,
then so should your scale. You and I would observe and record the data,
but the values recorded were independent of our disparate world views.
MR:
Yes, you stated, "You and I would OBSERVE and record the data. That
means there is an observer. Of course, I can agree with the idea of two
different observers with disparate world views arriving at objective
measurements. The way you initially came across is that objective
information could result in the total absence of observers which of
course is an absurdity.
"It's uncertain whether intelligence has any long term survival value.
Bacteria do quite well without it."
Stephen Hawking
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