On Fri, 29 Nov 1996 13:52:14 -0600 (CST), Pattle Pun wrote:
PP>Walter Bradley at the Creation Conference argued forcefully
>against the mathematical biology advocated by Kauffman and
>associates. He quoted one of them, John Horgan who quotes John
>Maynard Smith, one of the pioneers of mathemicatical biology, as
>referring to such simulation science "as fact-free science", where
>the mentioning of observational facts is considered to be in rather
>bad taste. Bradley also suggested, and I quote: "Self
>organization in complex systems which consist of large numbers of
>coupled chemical together have been demonstrated primarily in
>computer simulations. Again, the complexity or information that can
>be produced in an actual system depends on logistically arranging
>the many chemical reactions which take place in a very complicated
>way so that the required coupling can occur. While this is not a
>problem in the computer, it would be a "nightmare" in a real system
>of 1,000,000 chemical reactions. In reality, the information
>associated with the self organization in such systems is almost
>certainly less than the informational requirements to make the
>necessary spatial arrangements. Again we see that there do not seem
>to be any"free lunches" in nature when one is trying to explain the
>origin of information in nature."
Agreed. Mike Behe addresses this point too:
"Indeed, some proponents see great significance in the fact that they
can write short computer programs which display images on the screen
that resemble biological objects such as a clam shell. The
implication is that it doesn't take much to make a clam. But a
biologist or biochemist would want to know, if you opened the
computer clam, would you see a pearl inside? If you enlarged the
image sufficiently, would you see cilia and ribosomes and
mitochondria and intracellular transport systems and all the other
systems that real, live organisms need? To ask the question is to
answer it. In the article, Kauffman observes that `At some point
artificial life drifts off into someplace where I cannot tell where
the boundary is between talking about the world I mean, everything
out there-and really neat computer games and art forms and toys.'
More people are beginning to think that the drifting point occurs
very early." (Behe, 1996, p191)
On Fri, 29 Nov 1996 15:27:44 -0500, Terry M. Gray wrote:
TG>All I have to say is that the complexity field is in its infancy
>espeically in testing it in real physical/chemical systems. As a
>biochemist interested in biological self-organization (protein
>folding, macromolecular assembly), I can only say that the Kauffman
>type analysis rings true to me. TIME WILL TELL. I am happy to wait
>and see what happens and now merely say that it looks promising to
>me (I think that Kauffman is similarly cautious if you read him
>carefully and sympathetically). Why Bradley and Behe are so quick
>to dismiss this entire line of thinking is a mystery to me unless
>somehow they NEED this anti-evolutionary perspective for their
>Christian apologetic
Who says that "Bradley and Behe are...quick to dismiss this entire
line of thinking"? Their writings show they have considered
Kauffman's self-organisation theory at length and have then rejected
it, just as others are doing, including John Maynard Smith (who was
originaly sympathetic).
But it cuts both ways. One could equally argue that TEs "NEED"
"Kauffman" for *their* "*evolutionary* perspective" and *their*
"Christian apologetic"! :-)
[...]
TG>By the way, Horgan is NO complexity theorist--he is acientific
>journalist who wrote an anti-complexity essay for Scientific
>American and now his book *The End of Science*. It seems to me that
his main purpose in writing these things was simply to yank on
>people's chains.
Give us a break Terry! :-) Horgan has the title "Senior Writer"
after his name in that article. I would presume that one does not
get to be a "Senior Writer" at Scientific American by graduating from
the Astrology page of Women's Weekly! If Horgan does not have double
degrees in Science and English, I would be very surprised. His
article, "From Complexity to Perplexity", Scientific American, Vol.
272 No. 6, June 1995, pp74-79, which I have in front of me, is a
tour-de-force of the complexity theory field. I would urge other
Reflectorites, if they haven't done so, to read it for themselves.
I found this particularly interesting, apropos those who trust in
computer simulations:
"Some participants, particularly those associated with the institute,
expressed the hope that as computers grow in power, so will science's
ability to predict, control and understand nature. Others demurred.
Roger N. Shepard, a psychologist at Stanford University, worried that
even if we can capture nature's intricacies on computers, those
models might themselves be so intricate that they elude human
understanding. Francisco Antonio Doria, a Brazilian mathematician,
smiled ruefully and murmured, `We go from complexity to perplexity.'
Everybody nodded." (Horgan J., "From Complexity to Perplexity",
Scientific American, Vol. 272 No. 6, June 1995, p79)
On Sat, 30 Nov 1996 15:03:55, Glenn Morton wrote:
[...]
GM>Unless you are willing to believe in life in outer space, there is
>a mechanism (unknown to us at this moment) which is quite capable of
>producing non-racemic amino acids. Here is data from the Murchison
>meteorite in which non-racemic amino acids were extracted.
>
>amino acid d/l ratio in Murchison meteorite
> GLU ASP PRO LEU ALA
>H2O .322 .202 .342 .166 .682
>H2O .30 .30 .30 nd .60
>HCl .176 .126 .105 .029 .307
>
>~Michael H. Engel and
>Bartholomew Nagy, "Distribution and Enantiomeric Composition of
>Amino Acids in the Murchison Meteorite", Nature , 296, April 29,
>1982, p. 838.
>
>Some of these results show that something in space was able to
>produce 70-90% L amino acids. This concept that Christians propagate
>that nature can't produce anything but racemic forms is flawed. I
>don't know the mechanism but there is one. (See also Engel, Macko
>and Silfer, "Carbon Isotope Composition of Individual amino acids in
>the Murchison Meteorite," Nature 348, Nov. 1. 1990, pp 47-48)
If this conclusion which is accepted uncritically by Glenn, namely
that "something in space" (ie. "something" *100% naturalistic* -
after all God could just as easily create life in space as on Earth)
was able to produce 70-90% L amino acids", we could be sure it would
be shouted from the rooftops as an important part of the proof that
life was spontaneously generated from non-living chemicals. But it
isn't, so it is reasonable to conclude it wasn't. The Murchison
meteorite is discussed by a number of evolutionist writers, in the
context of the origin of life, but no definite conclusions are
reached based on the higher proportion of L-amino acids.
For example, Robert Shapiro notes the comparatively small amounts of
amino acids found in meteorites, compared to those produced in
Miller-Urey type simulation experiments (a good indication that the
latter are evidence of intelligent design, rather than undirected
natural processes):
"When a comparison is made of the identity and relative amounts of
amino acids present in these meteorites and those in the Miller-Urey
experiments, striking similarities are observed. We will cite two of
the scientists, J. G. Lawless and E. Peterson, directly: "Comparison
of the linear neutral amino acids present in the Murchison meteorite,
in laboratory chemical evolution experiments, and in a terrestrial
organism shows a marked similarity between the meteorite and
laboratory experiments and a significant difference between the
meteorite and E. coli." The Murchison meteorite is a much-studied
object that fell in Australia in 1969, and E. coli is the short form
of the name of an even more studied bacterial strain, Escherichia
coli, which inhabits our guts. The Miller-Urey experiment, then, may
have modeled some of the processes that took place among the reduced
gases in the original solar nebula to form compounds now preserved
within meteorites. I have used the word "some" just now and
emphasized "relative" in the above paragraph because amino acids and
other carboxylic acids occur in much lower absolute amounts in
meteorites than in Miller-Urey experiments. As suggested earlier,
the design of the spark apparatus may have favored these compounds
and enhanced their yields relative to the amounts that would be
expected in an appropriate natural situation. If we set aside this
enhancement, the lasting contribution of these experiments may be as
a model for certain chemical processes in outer space." (Shapiro R.,
"Origins: A Skeptic's Guide to the Origin of Life", Summit Books:
New York, 1986, p106)
Shapiro draws no conclusion from the preponderance of of L-amino
acids, which is difficult to understand (since he is a Professor of
Chemistry and an eminent OOL theorist), writing in a book that is all
about the naturalistic origin of life.
Orgel, another eminent OOL researcher, notes only that the Murchison
meteorite had amino acids of "roughly the same relative amounts" as
those Miller generated (although he admits even this is now
doubtful):
"In the early 1950s Stanley L. Miller, working in the laboratory of
Harold C. Urey at the University of Chicago, did the first experiment
designed to clarify the chemical reactions that occurred on the
primitive earth (right). In the flask at the bottom, he created an
"ocean" of water, which he heated, forcing water vapor to circulate
(arrows) through the apparatus. The flask at the top contained an
"atmosphere" consisting of methane (CH4), ammonia (NH3), hydrogen
(H2) and the circulating water vapor. Next he exposed the gases to a
continuous electrical discharge ("lightning"), causing the gases to
interact. Water-soluble products of those reactions then passed
through a condenser and dissolved in the mock ocean. The experiment
yielded many amino acids and enabled Miller to explain how they had
formed. For instance, glycine appeared after reactions in the
atmosphere produced simple compounds- formaldehyde and hydrogen
cyanide-that participated in the set of reactions shown below. Years
after this experiment, a meteorite that struck near Murchison,
Australia, was shown to contain a number of the same amino acids that
Miller identified (table) and in roughly the same relative amounts
(dots); those found in proteins are highlighted in blue. Such
coincidences lent credence to the idea that Miller's protocol
approximated the chemistry of the prebiotic earth. More recent
findings have cast some doubt on that conclusion." (Orgel L.E., "The
Origin of Life on the Earth", Scientific American, October 1994,
p54).
Again, no conclusions about the higher proportions of L-amino acids,
which is inexplicable in a major article on "The Origin of Life on
the Earth".
Davies says that "most scientists...remain sceptical" about the
claims of evdience for extraterrestrial "biological activity" in the
Murchison meteorite:
"More intriguing has been the study of meteorites, which does provide
some tantalizing evidence for alien microbes. The Murchison
meteorite which fell in Australia in 1969 has been extensively
examined for biological activity and found to contain dozens of amino
acids, including many that are common in terrestrial organisms.
There is also a hint of fossilized single-celled organisms, which the
British astronomer Fred Hoyle has claimed is clear evidence of
extraterrestrial life. Most scientists, however, remain sceptical.
Undoubtedly the definitive discovery of, say, a non-contaminant
living bacterium inside a meteorite would be immensely exciting and
important" (Davies P., "Are We Alone?: Philosophical Implications of
the Discovery of Extraterrestrial Life", Penguin: London, 1995, p12)
The last sentence implies that the reason they are sceptical is the
possibility of contamination by terrestrial biological material.
Indeed, Thaxton, et al, point out the Murchison meteorite was foundon
a sheep station and
"Added to this is the suggestive discovery of amino acids in
meteorites, including some that are important in proteins. The
Murchison meteorite, which fell in Australia in 1969, contained dl
amino acids (More recent reports challenge this interpretation. See
Michael H. Engel and Bartholomew Nagy, 1982. Nature 296, 837).
including some proteinous ones. The presence of dl-amino acids was
considered proof of extraterrestrial origin, and evidence that the
meteorite was free of contamination from earth life. This is
significant because the meteorite fell on a sheep farm, where
remaining uncontaminated would be no trifling feat!" (Thaxton C.B.,
Bradley W.L. & Olsen R.L., "The Mystery of Life's Origin:
Reassessing Current Theories, Lewis & Stanley: Dallas TX, 1992,
p192).
Croft, convincingly shows that the amino acids in the Murchison
meteorite were probably the result of pollen contamination:
"The failure to prove the presence of micro-organisms in meteorites
has spurred researchers to look for other signs of life, such as the
presence of known biochemicals. This is again another story of
discovery, refutation and controversy. The problem with this type of
study is that the meteorites must be obtained as soon as possible
after they arrive on earth. They must be as free as possible from
contamination with terrestrial products. And the biochemicals must
be isolated, preferably from the interior, and then be identified.
Contamination is always a problem in this type of research as many
meteorites have complex networks of deep cracks that extend to their
interior. Carbonaceous chondrites, in particular, are extremely
porous and friable so that they may readily absorb terrestrial
contaminants- even more so if they have undergone eager handling by
collectors. Between 2-6 % of the insoluble organic matter of
meteorites has been found by Drs J. Brooks and G. Shaw of Bradford
University to resemble sporopollenin. Sporopollenin is the very
stable material of which pollen capsules are made. It is this
substance that enables pollen to survive in ancient sediments. (The
significance of this finding will be discussed in detail shortly.)
On 28 September 1969 the famous Murchison meteorite fell in
Australia. The first studies on it were published by K. Kvenvolden
and his collaborators in the journal Nature some time in 1970 .
(Nature, (1970), 228, p.923). They reported finding racemic (i.e .
D, L) amino acids in the interior region of it. They then concluded
that as amino acids occur in living organisms as the L-isomer, then
the amino acids in the Murchison meteorite could not have arisen by
terrestrial contamination. Furthermore many of the amino acids were
unusual and not the sort found in the proteins of terrestrial
organisms, for example a-amino butyric acid and pipecolic acid.
Kvenvolden concluded therefore that he had discovered amino acids of
extraterrestrial origin. On 2 December 1970 NASA announced to the
world: 'The first positive identification of amino acids of
extraterrestrial origin has been made...The find is probably the
first conclusive proof of extraterrestrial chemical evolution.' (cf.
CETI by J. Stanley, Wyndham Pub, 1976).
Yet, over a decade later, this meteorite still continues to cause
controversy. Engel and Nagy have reported during 1982 in Nature that
several of the amino acids are, in fact, only partially racemized.
They concluded that the original amino acids in the meteorite were
completely racemic but that during its descent to earth some of the
amino acids may have undergone some sort of stereoselective
decomposition. (cf. Nature, 1982, 296, p837)
....At best one cannot be absolutely certain that, whatever one finds
in a meteorite, it did not originate on the earth itself. Even if
the meteorite were to have been collected soon after landing and if
it had the minimum of handling, one can never be sure that it hadn't
picked up biological material from a previous encounter with the
earth. It is now known that some meteorites collide with the earth's
atmosphere and are immediately ejected back into space, only to
return many years later...Any biological molecules found on
meteorites must have originated, one way or another, on earth. The
fact that the Apollo lunar samples failed to indicate biochemicals
confirms the view that life is only present here on earth. If
meteorites were loaded with biochemicals then one would have expected
to find a thick layer of organic dust on the surface of the moon.
This was not so.
I believe there is a simple explanation for the presence of
biochemicals in meteorites They arise from contamination by pollen
grains. Immense quantities of pollen are driven up into the upper
atmosphere by air currents. During the descent of any meteorite the
pollen grains become embedded into its surface cracks. Within the
pollen shell are an abundance of amino acids. They are all of the L-
type, but as the meteorite becomes hot, the amino acids racemize.
Finally, as it passes through layers of cloud, water droplets wash
out the amino acids from the pollen grains to leave a shell of
sporopollenin. What Brooks and Shaw had found was indeed
sporopollenin. Proof of this suggestion comes from an inspection of
the types of amino acid found in meteorites. They resemble very much
the amino acids present in honey; take for example, pipecolic acid,
a- amino butyric acid and b-alanine. These amino acids arise in
honey from pollen. In fact the amino acids found in meteorites are
characteristic of pollen. Pipecolic acid, for instance, is
characteristic of grass pollen. The presence of biochemicals in
meteorites does not indicate, as many would like to think, the
possibility of extraterrestrial life, nor indeed extraterrestrial
chemical evolution. They arise from pollen grains that are picked up
by the meteorite as it alls to earth"
(Croft L.R., "How Life Began", 1988, Evangelical Press, Durham,
England, p110-112)
Ironically, as Croft has already mentioned, it is the very higher
proportion of L-amino acids that is the strongest evidence that the
amino acids in the Murchison meteorites were of terrestrial origin.
As Aw also points out, it was previously thought they were 50/50,
which was taken as proof they were of *non*-terrestrial origin:
"More recently evidence for the abiotic synthesis of amino acids and
hydrocarbons have been found in the interior of the Murchison
meteorite, a carbonaceous chondrite which fell near Murchison,
Victoria, Australia, on September 28, 1969.3 Using a combination of
ion exchange chromatography, gas chromatography, and the mass
spectrometer the presence of glycine, alanine, valine, proline,
glutamic acid, 5-methyl alanine, and sarcosine were unequivocally
established. The presence of almost equal amounts of D and L forms
of valine, proline, alanine, and glutamic acid minimised the
possibility of terrestrial contamination which had rendered previous
reports of the presence of organic compounds in meteorites
inconclusive." (Aw S.E., "Chemical Evolution: An Examination of
Current Ideas", Master Books, San Diego: CA, 1982, pp19-20)
Happy New Year!
Steve
-------------------------------------------------------------------
| Stephen E (Steve) Jones ,--_|\ sejones@ibm.net |
| 3 Hawker Avenue / Oz \ Steve.Jones@health.wa.gov.au |
| Warwick 6024 ->*_,--\_/ Phone +61 9 448 7439 (These are |
| Perth, West Australia v my opinions, not my employer's) |
-------------------------------------------------------------------