paul@phs.UUCP (02/20/84)
<bug killer, I hope>
This is being sent to net.misc (where the evolution argument has been
going on) and net.bio (where the evolution argument really ought to be,
but may not exist at all sites). Please: Let's all create net.bio, and
use it, so I can un-subscribe to net.misc.
I recently received a brief (31 pages) monograph on "The Origin of Life"
by Carl R. Woese (Professor of Genetics and Development and of Microbiology
at U Illinois, U-C) from Carolina Biological Supply Company;
it is Carolina Biology Reader number 13 (and ISBN 0-89278-213-7). Those
interested in getting a copy might write to Carolina Biological Supply
Company (either [1] 2700 York Road, Burlington, NC 27215, or [2] Box 187,
Gladstone, Oregon 97027) or call their customer service department
(1-919-584-0381). I here present a few of Dr. Woese's arguments which are
pertinent to the netland origin of life debate.
Stereoisomers: preference for all-L or all-D forms
As has been noted, living systems use one of the two optical isomers,
e.g., L-amino acids for proteins, D-ribose for nucleic acids.
It should be noted that: [1]. "Polypeptides composed of only L- (or D-)
amino acids are more uniform in secondary and tertiary structure than those
constructed randomly of D-, L- mixtures, and so may well be biologically
'superior'." [2]. "Chemists have shown that once a polypeptide chain begins
to polymerize... as either a pure D- or pure L- form, then it will
preferentially add amino acids of the same type as polymerization continues."
[3]. "The difficulty comes in trying to understand why biology should be based
upon L-amino acids rather than D-amino acids. Indeed, many scientists feel
this question is unanswerable, for it is merely a matter of chance whether the
first proteins started with L-amino acids or D-amino acids. Were the process
to start over, life on earth may well be of the opposite handedness."
Beginnings in the ocean
Again as noted before, there is a problem with biochemistry in water:
"most, if not all, of the important chemical reactions that yield
biomolecules involve the elimination of water. An ocean would favor the
reversal of such reactions (by mass action). Therefore, any polymers or other
biomolecules formed would tend to be hydrolyzed."
There are two classes of solutions to this problem. First, one can assume
that local conditions in the ocean may have been favorable even while
global conditions were not. For example, [1] "reactions might have occurred
among molecules adsorbed (concentrated) on clay sediments at the ocean
bottom [and elsewhere he notes that 'certain... clays can adsorb one optical
isomer of certain biomolecules better than the other.']." [2]. "Oil slicks
presumed to be on the ocean's surface would present high concentrations
of organic compounds, as well as hydrophobic conditions, and so could serve
as areas of chemical, even photochemical, reactivity." [3]. "Tidal
pools would evaporate in the sun, becoming not only concentrated in whatever
was dissolved in ocean water, but very warm as well; here the vital reactions
might have occurred." [4]. "Similarly, lava flowing into the ocean from
volcanoes could lead to more reactive conditions."
Another class of solutions is to "do away with the ocean during that
critical, ititial phase in life's origin." For example, [1] "The early
Earth could have... possessed vast cloud banks, containing not water
per se, but salt water... [explanation presented, but omitted here, of
how this might occur]... Adding to this picture an atmosphere rich in
carbon dioxide that also contained hydrogen and other volcanic gases
permits the entire scenario of chemical synthesis to occur in and around
the cloud droplets." [2]. Towe suggested that one might imagine "the
Earth's surface initially as hot, but not too hot to be damp -- there
being to little water on the surface to make oceans... [another explanation
omitted here]... In this case, the Earth's surface could have become
coated with organic compounds -- an incredible scum."
UV light and lightning: energy sources
Woese doesn't believe in UV light and lightning as the energy sources.
Just what he believes isn't terribly clear, other than that he doesn't
think that there has been sufficient investigation of the following
energy sources: [1] visible light, [2] infrared radiation, and
[3] chemical imbalances arising because the Earth then was far from
temperature equilibrium. To get further with this, you'll have to do
some reading (and perhaps some experiments) on your own; I haven't time
to chase it down.
Concluding remarks
Nothing here presented proves that non-miraculous abiogenesis occurred,
or could occur. Whether or not any of Woese's speculations (or those of
the researchers he knows about) are correct, the point is that a disproof
of a speculation shows that the particular speculation is in error, not
that [1] all other speculations of related classes are wrong, and
particularly not that [2] some other speculation is right.
References:
Woese provides a few (this is not the sort of monograph where more than
a few are called for). Those interested in further enlightenment might
try the following from his list (I've seen none of them, nor will I):
Fox, G.E., et al. 1980. The phylogeny of prokaryotes. Science 209:
457-463.
Halvorsson, H.O. and K.E. VanHolde (Eds.). 1980. The Origins of Life
and Evolution. MBL Lectures in Biology, Vol. 1, Alan R. Liss, N.Y.
Schopf, J.W. (Ed.). 1983. Origin and Evolution of Earth's Earliest
Biosphere, Princeton University Press.
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Paul Dolber @ Duke U Med Ctr (...duke!phs!paul).seifert@ihuxl.UUCP (D.A. Seifert) (02/21/84)
> [2]. "Oil slicks presumed to be on the ocean's surface would > present high concentrations of organic compounds, as well as > hydrophobic conditions, and so could serve as areas of chemical, > even photochemical, reactivity." Oil slicks? And where did this oil come from? I always thought that oil came from plants and animals. Ah, a new version of the "chicken and the egg" question: which came first, the oil, or the plants and animals? Is there some other source of oil they didn't tell us about? -- _____ /_____\ "Happiness is a warm puppy" /_______\ Snoopy |___| ____|___|_____ ihnp4!ihuxl!seifert
bill@utastro.UUCP (William H. Jefferys) (02/22/84)
>> Oil slicks? And where did this oil come from? I always thought >> that oil came from plants and animals. Ah, a new version of the >> "chicken and the egg" question: which came first, the oil, or the >> plants and animals? >> >> Is there some other source of oil they didn't tell us about? Warning: The following is highly speculative! Professor Tommy Gold, of Cornell, thinks that most of the liquid and gaseous hydrocarbons on Earth are of nonbiological origin, having been trapped beneath the surface of the Earth when it was formed. There was an article about this recently in the Wall Street Journal. Needless to say, this idea has stirred up a hornet's nest of controversy, and most scientists don't believe it. Anyway, you might be interested in digging up the article, which is very interesting. Gold, by the way, is one of the originators of the Steady State theory of the universe (wrong) and invented the rotating neutron model for pulsars (right). His ideas are not lightly dismissed. (His theory, if correct, would not give comfort to creationists, however.) -- Bill Jefferys 8-% Astronomy Dept, University of Texas, Austin TX 78712 (USnail) {ihnp4,kpno,ctvax}!ut-sally!utastro!bill (uucp) utastro!bill@ut-ngp (ARPANET)
bhayes@glacier.UUCP (05/11/86)
In article <1180@umcp-cs> mangoe@umcp-cs writes: > >This also suggests why we don't have centaurs, pegasi, and various similar >things. It's generally easier to modify the existing features than it is to >stick something new in. > >C. Wingate This is very important for an understanding of evolution. It is, in fact, not only harder, but impossible to "stick something new in". Evolution can only modify existing parts and often does so in a damned kludgy way. A readable book on this [and many other] subjects is Stephen J. Gould's The Panda's Thumb. The title essay is about the author's trip to the national zoo to see the giant pandas. When he got there, he noticed that they ate bamboo by stripping the leaves from the stalk by putting it between the palm and the thumb and pulling. But aren't humans the only species with opposable thumbs? Well, I won't give away the ending to this little mystery. Turn off your screen and read the book. Barry Hayes