"Stephen E. Jones" writes
in message <200008272028.EAA27699@urban.iinet.net.au>:
> Reflectorites
>
> On Fri, 18 Aug 2000 09:58:38 -0700, Tedd Hadley wrote:
>
> [...]
>
> >SJ>1) do we know that these "putrefactive bacteria" have always been around
> >>from the beginning cleaning up any "amino and nucleic acids" produced?
>
> TH>We know bacteria are among the oldest life forms known, so its
> >a pretty good assumption.
>
> So it is only an "assumption"? We don't *know* (i.e. there is no
> actual *evidence* that "putrefactive bacteria" have always been around?
Why this unwarranted focus on modern putrefactive bacteria?
It is no assumption that bacteria are among the oldest life
forms, and it's simple observation that they've evolved
to consume and metabolize a wide variety of energy sources.
If amino acids were as common then as they are now, they'd
very likely be metabolized by bacteria.
> If "putrefactive bacteria are anerobic" how do they live in the
> gut which has air in it?
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.
> TH>First, the putrefactive bacteria are pretty much everywhere,
>>not just in the human intestinal tract, since decaying plant or
>>animal matter is found pretty much everywhere.
>
> What is the evidence that *modern day* bacteria consume raw amino and
> nucleic acids that are produced *non-biologically*?
>
> I would have thought that 4 billion years later, with such a
> vast quantity o f "decaying plant or animal matter" available,
> bacteria might have specialised to only go after "decaying plant
> or animal matter", not the small quantities of amino or nucleic
> acids produced abiotically?
For most amino acids, such specialized bacteria should see no
difference between abiotic proteins and the "natural" proteins.
The only difference could be what you mentioned earlier, the
handedness of the molecule. Since there are modern bacteria
that have ability to switch the handedness of certain proteins
from L to D (since they require one particular D version of an
amino acid in the bacterial cell wall) it seems likely the
presence of D-amino acid for long would represent a niche to be
filled. 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.
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.
> TH>However, four billion years ago, who knows? Maybe the first
> >life form thrived on a soup of life precursors.
> What "soup" would that be exactly?:
Who knows? But, as you point out, probably not prebiotic
soup of Oparin's scenario.
<snip>
> > been "taking place" in laboratories since at least *1953*,
> > i.e. 47 years (!) and no life has yet emerged spontaneously.
> TH>Well, gosh, medical research has been going on since the
> *1800*s, i.e. 200 years (!) and we still can't cure the common
> >cold.
> My understanding is that "the common cold" is actually a syndrome
> of about *200* different strains of virii:
Probably more than 200; that would assume that you need only
catch cold 200 times and then you're home free.
It's the same for most disease virii -- hundreds of different
strains have evolved to evade the immune system and new one
evolves roughly every year, at least in the case of the flu
virus. This's the problem and the reason it's difficult to cure
the common cold.
So the reason the common cold hasn't been cured after hundreds
of years of reaseach is because *the problem is a lot more
difficult than it looks*. 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*.
<snip>
> TH>I guess we ought to give up know and just conclude God created
> >Viral Rhinitis to make life difficult for us? :)
> In the case of the virii (and most scientific problems), generally
> the case has been that as science's knowledge has increased,
> the solution to the problems become apparent, even though in
> some cases (like the common cold) it also became apparent that
> the resources required to solve the problem was not warranted
> by the cost.
Why not just engineer an antibody that can mutate right along
with a virus? Simple right?
There is no shortage of simple-sounding solutions for medical
and abiogenesis research.
> But in the case of the origin of life, the problem is not that
> we don't know enough, but that we now know *too much*:
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
If you can't do that, I'll assume that the problem is that
we *don't know enough to rule it out*.
<snip>
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