Religions > Atheism > Behe's next load of pathetic bullcrap. "The Edge of Evolution"
| Topic: |
Religions > Atheism |
| User: |
"Michael Gray" |
| Date: |
10 Jun 2007 09:15:58 PM |
| Object: |
Behe's next load of pathetic bullcrap. "The Edge of Evolution" |
Evolution: God as Genetic Engineer
by Sean B. Carroll, Science Magazine
http://www.sciencemag.org/cgi/content/full/316/5830/1427
The Edge of Evolution: The Search for the Limits of Darwinism, by
Michael J. Behe
Free Press, New York, 2007. 331 pp. $28, C$33.99. ISBN 9780743296205.
"The Lord hath delivered him into mine hands."
"Those are the words that Thomas Huxley, Darwin's confidant and
staunchest ally, purportedly murmured to a colleague as he rose to
turn Bishop Samuel Wilberforce's own words to his advantage and rebut
the bishop's critique of Darwin's theory at their legendary 1860
Oxford debate. They are also the first words that popped into my head
as I read Michael J. Behe's The Edge of Evolution: The Search for the
Limits of Darwinism. In it, Behe makes a new set of explicit claims
about the limits of Darwinian evolution, claims that are so poorly
conceived and readily dispatched that he has unwittingly done his
critics a great favor in stating them.
In Darwin's Black Box: The Biochemical Challenge to Evolution (1),
Behe had forwarded the notion that certain biochemical systems were
"irreducibly complex," could not have evolved stepwise by Darwinian
mechanisms, and thus were intelligently designed. Since that earlier
book, Behe has played a key role in the intelligent design (ID)
movement, including a star turn as a defense witness in the 2005 Dover
school board case. Despite his testimony--or, I should say, partly
because of what he said (2)--ID was ruled to be a religious concept
and its teaching in public schools unconstitutional.
Behe, a professor of biochemistry at Lehigh University, has found an
audience among various flavors of creationists who find Darwinian
evolution incompatible with their religious views and see scientific
validation in Behe's claims. Clearly, this book's main audience would
be that constituency, although they will find some parts very
discomfiting. For instance, Behe explicitly accepts the ability of
random mutation and selection to account for the variation within and
differences between closely related species (but not higher taxa such
as vertebrate classes). He also accepts (as he has before) the
4.5-billion-year age of Earth and that we share a common ancestor with
chimpanzees. That certainly won't go over well in some camps.
Behe also explores some examples of Darwinian evolution at the
molecular level, including an extensive treatment of the evolutionary
"trench warfare" fought between humans and malarial parasites over the
millennia--all in the context of what Darwinian evolution "can do." So
what's the problem?
The problem is what Behe asserts Darwinian evolution can't do: produce
more "complex" changes than those that have enabled humans to battle
malaria or allowed malarial parasites to evade the drugs we throw at
them. Behe's main argument rests on the assertion that two or more
simultaneous mutations are required for increases in biochemical
complexity and that such changes are, except in rare circumstances,
beyond the limit of evolution. He concludes that "most mutations that
built the great structures of life must have been nonrandom." In
short, God is a genetic engineer, somehow designing changes in DNA to
make biochemical machines and higher taxa.
But to arrive at this conclusion, Behe relies on invalid assertions
about how genes and proteins evolve and how proteins interact, and he
completely ignores a huge amount of experimental data that directly
contradicts his faulty premises. Unfortunately, these errors are of a
technical nature and will be difficult for lay readers, and even some
scientists (those unfamiliar with molecular biology and evolutionary
genetics), to detect. Some people will be hoodwinked. My goal here is
to point out the critical flaws in Behe's key arguments and to guide
readers toward some references that illustrate why what he alleges to
be beyond the limits of Darwinian evolution falls well within its
demonstrated powers.
Behe's chief error is minimizing the power of natural selection to act
cumulatively as traits or molecules evolve stepwise from one state to
another via intermediates. Behe states correctly that in most species
two adaptive mutations occurring instantaneously at two specific sites
in one gene are very unlikely and that functional changes in proteins
often involve two or more sites. But it is a non sequitur to leap to
the conclusion, as Behe does, that such multiple-amino acid
replacements therefore can't happen. Multiple replacements can
accumulate when each single amino acid replacement affects
performance, however slightly, because selection can act on each
replacement individually and the changes can be made sequentially.
Behe begrudgingly allows that only "rarely, several mutations can
sequentially add to each other to improve an organism's chances of
survival." Rarely? This, of course, is the everyday stuff of
evolution. Examples of cumulative selection changing multiple sites in
evolving proteins include tetrodotoxin resistance in snakes (3), the
tuning of color vision in animals (4), cefotaxime antibiotic
resistance in bacteria (5), and pyrimethamine resistance in malarial
parasites (6)--a notable omission given Behe's extensive discussion of
malarial drugresistance.
Behe seems to lack any appreciation of the quantitative dimensions of
molecular and trait evolution. He appears to think of the functional
features of proteins in qualitative terms, as if binding or catalysis
were all or nothing rather than a broad spectrum of affinities or
rates. Therefore, he does not grasp the fundamental reality of a
mutational path that proteins follow in evolving new properties.
This lack of quantitative thinking underlies a second, fatal blunder
resulting from the mistaken assumptions Behe makes about protein
interactions. The author has long been concerned about protein
complexes and how they could or, rather, could not evolve. He argues
that the generation of a single new protein-protein binding site is
extremely improbable and that complexes of just three different
proteins "are beyond the edge of evolution." But Behe bases his
arguments on unfounded requirements for protein interactions. He
insists, based on consideration of just one type of protein structure
(the combining sites of antibodies), that five or six positions must
change at once in order to make a good fit between proteins--and,
therefore, good fits are impossible to evolve. An immense body of
experimental data directly refutes this claim. There are dozens of
well-studied families of cellular proteins (kinases, phosphatases,
proteases, adaptor proteins, sumoylation enzymes, etc.) that recognize
short linear peptide motifs in which only two or three amino acid
residues are critical for functional activity [reviewed in (7-9)].
Thousands of such reversible interactions establish the protein
networks that govern cellular physiology.
Very simple calculations indicate how easily such motifs evolve at
random. If one assumes an average length of 400 amino acids for
proteins and equal abundance of all amino acids, any given two-amino
acid motif is likely to occur at random in every protein in a cell.
(There are 399 dipeptide motifs in a 400-amino acid protein and 20 20
= 400 possible dipeptide motifs.) Any specific three-amino acid motif
will occur once at random in every 20 proteins and any four-amino acid
motif will occur once in every 400 proteins. That means that, without
any new mutations or natural selection, many sequences that are
identical or close matches to many interaction motifs already exist.
New motifs can arise readily at random, and any weak interaction can
easily evolve, via random mutation and natural selection, to become a
strong interaction (9). Furthermore, any pair of interacting proteins
can readily recruit a third protein, and so forth, to form larger
complexes. Indeed, it has been demonstrated that new protein
interactions (10) and protein networks (11) can evolve fairly rapidly
and are thus well within the limits of evolution.
Is it possible that Behe does not know this body of data? Or does he
just choose to ignore it? Behe has quite a record of declaring what is
impossible and of disregarding the scientific literature, and he has
clearly not learned any lessons from some earlier gaffes. He has again
gone "public" with assertions without the benefit (or wisdom) of first
testing their strength before qualified experts.
For instance, Behe once wrote, "if random evolution is true, there
must have been a large number of transitional forms between the
Mesonychid [a whale ancestor] and the ancient whale. Where are they?"
(12). He assumed such forms would not or could not be found, but three
transitional species were identified by paleontologists within a year
of that statement. In Darwin's Black Box, he posited that genes for
modern complex biochemical systems, such as blood clotting, might have
been "designed billions of years ago and have been passed down to the
present … but not 'turned on'." This is known to be genetically
impossible because genes that aren't used will degenerate, but there
it was in print. And Behe's argument against the evolution of flagella
and the immune system have been dismantled in detail (13, 14) and new
evidence continues to emerge (15), yet the same old assertions for
design reappear here as if they were uncontested.
The continuing futile attacks by evolution's opponents reminds me of
another legendary confrontation, that between Arthur and the Black
Knight in the movie Monty Python and the Holy Grail. The Black Knight,
like evolution's challengers, continues to fight even as each of his
limbs is hacked off, one by one. The "no transitional fossils"
argument and the "designed genes" model have been cut clean off, the
courts have debunked the "ID is science" claim, and the nonsense here
about the edge of evolution is quickly sliced to pieces by
well-established biochemistry. The knights of ID may profess these
blows are "but a scratch" or "just a flesh wound," but the argument
for design has no scientific leg to stand on."
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| User: "johac" |
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| Title: Re: Behe's next load of pathetic bullcrap. "The Edge of Evolution" |
11 Jun 2007 12:54:28 AM |
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In article <s2cp639639hd87f75kn2dmk7m29c7q5qm7@4ax.com>,
Michael Gray <mikegray@newsguy.com> wrote:
Evolution: God as Genetic Engineer
by Sean B. Carroll, Science Magazine
http://www.sciencemag.org/cgi/content/full/316/5830/1427
The Edge of Evolution: The Search for the Limits of Darwinism, by
Michael J. Behe
Free Press, New York, 2007. 331 pp. $28, C$33.99. ISBN 9780743296205.
<snip fine article>
The continuing futile attacks by evolution's opponents reminds me of
another legendary confrontation, that between Arthur and the Black
Knight in the movie Monty Python and the Holy Grail. The Black Knight,
like evolution's challengers, continues to fight even as each of his
limbs is hacked off, one by one. The "no transitional fossils"
argument and the "designed genes" model have been cut clean off, the
courts have debunked the "ID is science" claim, and the nonsense here
about the edge of evolution is quickly sliced to pieces by
well-established biochemistry. The knights of ID may profess these
blows are "but a scratch" or "just a flesh wound," but the argument
for design has no scientific leg to stand on."
That's not only true of creationists, but also of many of the trolls
that we see around here. We hack them into little pieces and the little
pieces still hop around yipping and yapping at us.
--
John #1782
"We should always be disposed to believe that which appears to us to be
white is really black, if the hierarchy of the church so decides."
- Saint Ignatius Loyola (1491-1556) Founder of the Jesuit Order.
.
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| User: "Michael Gray" |
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| Title: Re: Behe's next load of pathetic bullcrap. "The Edge of Evolution" |
11 Jun 2007 02:44:46 AM |
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On Sun, 10 Jun 2007 22:54:28 -0700, johac
<jhachmann@remove.sbcglobal.net> wrote:
- Refer: <jhachmann-CE295B.22542810062007@news.giganews.com>
In article <s2cp639639hd87f75kn2dmk7m29c7q5qm7@4ax.com>,
Michael Gray <mikegray@newsguy.com> wrote:
Evolution: God as Genetic Engineer
by Sean B. Carroll, Science Magazine
http://www.sciencemag.org/cgi/content/full/316/5830/1427
The Edge of Evolution: The Search for the Limits of Darwinism, by
Michael J. Behe
Free Press, New York, 2007. 331 pp. $28, C$33.99. ISBN 9780743296205.
<snip fine article>
The continuing futile attacks by evolution's opponents reminds me of
another legendary confrontation, that between Arthur and the Black
Knight in the movie Monty Python and the Holy Grail. The Black Knight,
like evolution's challengers, continues to fight even as each of his
limbs is hacked off, one by one. The "no transitional fossils"
argument and the "designed genes" model have been cut clean off, the
courts have debunked the "ID is science" claim, and the nonsense here
about the edge of evolution is quickly sliced to pieces by
well-established biochemistry. The knights of ID may profess these
blows are "but a scratch" or "just a flesh wound," but the argument
for design has no scientific leg to stand on."
That's not only true of creationists, but also of many of the trolls
that we see around here. We hack them into little pieces and the little
pieces still hop around yipping and yapping at us.
None shall pass.
--
.
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| User: "johac" |
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| Title: Re: Behe's next load of pathetic bullcrap. "The Edge of Evolution" |
11 Jun 2007 06:35:51 PM |
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In article <8avp63dllbgtguqck331782a824a91itoo@4ax.com>,
Michael Gray <mikegray@newsguy.com> wrote:
On Sun, 10 Jun 2007 22:54:28 -0700, johac
<jhachmann@remove.sbcglobal.net> wrote:
- Refer: <jhachmann-CE295B.22542810062007@news.giganews.com>
In article <s2cp639639hd87f75kn2dmk7m29c7q5qm7@4ax.com>,
Michael Gray <mikegray@newsguy.com> wrote:
Evolution: God as Genetic Engineer
by Sean B. Carroll, Science Magazine
http://www.sciencemag.org/cgi/content/full/316/5830/1427
The Edge of Evolution: The Search for the Limits of Darwinism, by
Michael J. Behe
Free Press, New York, 2007. 331 pp. $28, C$33.99. ISBN 9780743296205.
<snip fine article>
The continuing futile attacks by evolution's opponents reminds me of
another legendary confrontation, that between Arthur and the Black
Knight in the movie Monty Python and the Holy Grail. The Black Knight,
like evolution's challengers, continues to fight even as each of his
limbs is hacked off, one by one. The "no transitional fossils"
argument and the "designed genes" model have been cut clean off, the
courts have debunked the "ID is science" claim, and the nonsense here
about the edge of evolution is quickly sliced to pieces by
well-established biochemistry. The knights of ID may profess these
blows are "but a scratch" or "just a flesh wound," but the argument
for design has no scientific leg to stand on."
That's not only true of creationists, but also of many of the trolls
that we see around here. We hack them into little pieces and the little
pieces still hop around yipping and yapping at us.
None shall pass.
Yeah.
--
John #1782
"We should always be disposed to believe that which appears to us to be
white is really black, if the hierarchy of the church so decides."
- Saint Ignatius Loyola (1491-1556) Founder of the Jesuit Order.
.
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