At 04:52 PM 1/10/00 EST, Mike wrote:
>Brian:
>
>>>This would indicate, to me anyway, that the ball is back in
>>>Miller's court.
>
Mike:
>
> >I'm not so sure. Exactly what amino acids were condensed into
> >oligopeptides? And didn't they get anything larger than six glycines
> >linked together?
>
>Brian:
>
>>(1) glycine (2) no
>
>>You seem to be missing the point. Go back and read the quotes
>>that Steve gave. The implication of Miller's experiment is that
>>the hydrothermal vents are a sink for organic materials. This
>>creates a potentially serious problem due to the relatively
>>rapid circulation of the early oceans through these vents.
>>Matsuno's results call Miller's into question. The vents may
>>not have been destructive. They may also have been generative.
>
Mike:
>Maybe I'm missing the point, but I don't see how Matsuno's results
>call Miller's into question (at least serious question). As you suggested,
>I reread the quotes, where both talk about these vents destroying
>rather than creating "complex organic compounds." I don't consider
>glycine a "complex organic compound," thus its survival doesn't
>seem all that relevant. Matsuno's results would be more significant
>if they dealt with other more complex amino acids and short peptides
>composed of these amino acids. The Miller/Bada paper looked at
>leucine, serine, and aspartate and found them all to decompose rapidly.
>Furthermore, they too noted that glycine was stable under these heated
>conditions (more accurately, glycine concentrations rose as the more
>complex amino acids decomposed).
>
>Also, don't forget that amino acids are not the only organics important
>in abiogenesis. The ingredients of the RNA world would quickly
>be decomposed under these hot vents condition (for example, sugars
>survive only a few seconds at these high temps).
>
>So I still don't see how the Matsuno results put the ball back in Miller's
>court as they didn't address anything other than glycine.
>
OK, these are good points. I need to go back and look at my old references.
As I mentioned before, Miller's experiments had been challenged by several
people. I was able to quickly find two references for this by E.L. Shock:
Shock, E.L. 1990, "Geochemical Constraints on the Origin of Organic
Compounds in Hydrothermal Systems," _Origin of Life and Evolution
of the Biosphere_, <20>:331-367, 1990.
Shock, E.L. 1992, "Hydrothermal Organic Synthesis Experiments," _Origin
of Life and Evolution of the Biosphere_, <22>:135-146.
Let me see what else I can dig up, including responses to Shock by Miller
and/or Bada.
I also decided to spend a couple of hours browsing through our electronic
database of journals to see what I could come up with. As I mentioned before
its been a few years since I looked at this. I was really surprised at
how much has been done in this area in just the last few years (in support
of Susan's earlier speculation). I'll try to make some sense of this in
view of your comments above. Let me just throw out one tidbit I noticed
while stapling papers. One author reports that the yields of amino acids
obtained in hydrothermal conditions exceeds (by an order of magnitude) that
obtained in electrical discharge experiments even for the most optimistically
reducing atmospheres.
Oh, let me take a little detour before I go on. I imagine some people who
have followed my posts on the OOL might be a little confused. In some cases,
for example when debating Kevin O'Brien :), I'm sure I sound like a creationist,
objecting to everything he says. Now I probably sound like a hardened
materialist :).
The reason for this is that I typically have this knee jerk reaction when I
feel a subject is not being presented objectively. I can, in such a situation,
play a pretty good Devil's advocate for either side. My own view on this is
that I expect the origin of life on Earth occurred naturally, i.e. without
need of *direct* intervention by God. Nevertheless, I do not feel that anyone
is anywhere close to figuring out how it happened. In fact, I rather suspect
we may never figure it out.
Now I would like to ask you a question. What do you think ID has to offer
with regard to the question of the origin of life? Is there something more
than the negative argument from the false or missing alternative?
Brian Harper | "If you don't understand
Associate Professor | something and want to
Applied Mechanics | sound profound, use the
The Ohio State University | word 'entropy'"
| -- Morrowitz
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