"Stephen E. Jones" writes
in message <200009142225.e8EMPh527970@ursa.calvin.edu>:
<snip>
> TH>If amino acids were as common [billions of years ago] as they are now,
> >they'd very likely be metabolized by bacteria.
>
> Is there any hard evidence for this though?
Hard evidence that bacteria metabolized amino acids billions of
years ago? I don't know. However, I've already explained why
such a hypothesis is reasonable and that's about the best anyone
can do under the circumstances.
>I have a book on microbiology which doesn't say anything about
> bacteria eating amino acids and nucleic acids.
Look up putrefactive bacteria or any of those varieties that ferment
proteins. There are probably thousands of species.
<snip>
> TH>The gut (small & large intenstine, not stomach, by the way) doesn't
> >have an appreciable quantity of O2 in it (nor nitrogen so
> >"air" is not the case) but occasionally has small quantities of
> >bacterial fermentation bioproducts such as hydrogen, carbon
> >dioxide, and methane.
>
> According to the above text on page 274, there are *both* aerobic and
> anaerobic bacteria in human and animal intestinal tracts.
That sounds right to me.
<snip>
> TH>For most amino acids, such specialized bacteria should see no
> >difference between abiotic proteins and the "natural" proteins.
> See above on "chemotaxis". I would need hard evidence of this.
>
> I would think it unlikely that modern day bacteria would be
> attracted to raw amino and nucleic acids.
How the heck do you think dead plant and animal matter decays
then?? You don't really think that we'll find a big pile of
amino acids in some unfortunate's coffin after the appropriate
decomposition interval?
<snip>
> TH>Likewise, for the amino acids that do not occur in
> >life, it would seem that a buildup for any length of time would
> >represent an energy source to be exploited
>
> Is there any evidence that bacteria eat non-biological amino acids?
Well, point me to a source of non-biological amino acids
and I'll check.
> I would consider this unlikely because of the ready supply of cellular
> materials they can already exploit.
Cellular materials from what or where? What happens when that
runs out? All the bacteria just die, like that, with a food
source available right there with only minor chemical differences?
> TH>In the race between a possible new life precursor from abiotically
> >produced amino acids and evolution of a new bacterial strain
> >able to metabolize those amino acids, I'd put my money on the
> >bacteria every time.
>
> Tedd might lose his money. There would be good reasons why bacteria
> would *not* metabolize amino acids.
Well, given that bacteria now seem to have no problem and that
amino acids have been available as a potential food source for
billions of years, my money looks safer than McDonald's stock.
> >>TH>However, four billion years ago, who knows? Maybe the first
> >>>life form thrived on a soup of life precursors.
>
> >SJ>What "soup" would that be exactly?:
>
> TH>Who knows? But, as you point out, probably not prebiotic
> >soup of Oparin's scenario.
>
> If not Oparin's, what "prebiotic soup" then?
>
> "The existence of a prebiotic soup is crucial to the whole scheme.
> Without an abiotic accumulation of the building blocks of the cell
> no life could ever evolve. If the traditional story is true, therefore,
> there must have existed for many millions of years a rich mixture of
> organic compounds in the ancient oceans and some of this material
> would very likely have been trapped in the sedimentary rocks lain
> down in the seas of those remote times. Yet rocks of great antiquity
> have been examined over the past two decades and in none of them
> has any trace of abiotically produced organic compounds been
> found. Most notable of these rocks are the dawn rocks" of Western
> Greenland, the earliest dated rocks on Earth, considered to be
> approaching 3,900 million years old. So ancient are these rocks that
> they must have been lain down not long after the formation of the
> oceans themselves and perhaps only three hundred to four hundred
> million years after the actual formation of the Earth. And the
> Greenland rocks are not exceptional. Sediments from many other
> parts of the world dated variously between 3,900 million years old
> and 3,500 million years old also show no sign of any abiotically
> formed organic compounds.
Further research appears to prove this wrong.
See http://www.uta.edu/geology/geol1425earth_system/images/gaia_chapter_10/Early_Life.htm
which indicates that there *is* signs of organic material in
those rocks.
| The simplest interpretation of the carbon isotopic data in Mojzsis
| et al. (1996) is that the organisms responsible for the light carbon
| signature in the oldest known terrestrial sediments were metabolically
| complex, perhaps comprising populations of phosphate-utilizing
| photoautotrophs and chemoautotrophs. These data may point to the
| presence of diverse photosynthesizing, methanogenic, and methylotrophic
| bacteria on Earth before 3850 Ma (Mojzsis and Arrhenius, 1998;
| Mojzsis et al., 1999b). Not only had life taken firm hold on Earth
| by the close of the Hadean era, but it also appears to have evolved
| far enough away from its origin to create an interpretable signature
| in carbon isotopes.
<snip>
> TH>In the same way, the origin of life
> >will very likely require at least as much research because *it
> >is a lot more difficult than it looks*.
>
> *If* the origin of life was fully naturalistic it should be one
> of the *easiest* problems of evolution to solve. That is because,
> if it was solely by undirected natural chemical processes, there
> is only a limited number of these (though large) and it should
> be fully deterministic and therefore completely reproducible in
> a laboratory.
That doesn't follow logically. 1) the existence of advanced
life now very likely eliminates all evidence of the proper
configuration of environments and chemicals; 2) the number of
configurations of environments and chemicals is still astronomical.
<snip>
> TH>There is no shortage of simple-sounding solutions for medical
> >and abiogenesis research.
>
> I regard Tedd's dragging in of the common cold as just a
> red-herring. There is little or no connection between curing
> the common cold and demonstrating an abiotic origin of life.
The only connection I wish to stress is that they both seem to
be simple problems which turn out to be difficult to solve.
No red-herring.
> Anyway, it defeats Tedd's own argumenmt. Researchers have made
> and are making steady progress in medical research over the last
> 40+ years, but there is no such steady progress being made in
> abiogenesis. What origin of life reasearchers report is
Heh, post something up to date, not 12 years out of date!
<snip>
> TH>Okay, let's try a little experiment. If you claim we know too
> >much, I have a simple request. Read the publications at the
> >following URL and tell me what we know about the conditions of
> >early earth that should eliminate this research as possible
> >candidate for origin of simple replicators:
>
> The only way to "eliminate" possibilities is to test them all
> out. There are probably thousands of labs across the world who
> could divide-and-conquer this problem.
Don't forget that the availability of research grants severely
constrains this approach.
> It should be a lot easier and cheaper than trying to find life on Mars or
> Europa. Besides, even if they did find life on another planet, they would
> still need to work out how it originated.
It sure is easier getting public funding for alien-life form study
than for abiogenesis. I think most folks still see abiogenesis
as a threat to religious belief.
TH> Okay, let's try a little experiment. If you claim we know too
> much, I have a simple request. Read the publications at the
> following URL and tell me what we know about the conditions of
> early earth that should eliminate this research as possible
> candidate for origin of simple replicators:
>
> http://ool.weizmann.ac.il/publications.html
>
> Reading a number of "publications" may not be "a simple request".
<snip>
Exactly. There is a great deal of material there that you can't
simply dismiss out of hand because you don't know enough about
early Earth conditions to rule it out.
We do *not* know too much about abiogenesis, we know too little
and that is amply demonstrated by the variety of approaches
being attempted, suggested and often rejected.
Now I think most creationists have a different explanation for
the quantity of abiogenetic research out there and that is:
"It's an atheist conspiracy to make it *appear* to the public
like much progress is being made when in reality the work is
mostly fraudulent."
I think, Stephen, this is fairly close to your own belief as
well, is it not?
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