Reflectorites
This one is *really* late. My apologies!
On Mon, 28 Aug 2000 10:07:07 -0700, Tedd Hadley wrote:
[...]
>>TH>We know bacteria are among the oldest life forms known, so its
>>>a pretty good assumption.
>SJ>So it is only an "assumption"? We don't *know* (i.e. there is no
>>actual *evidence* that "putrefactive bacteria" have always been around?
TH>Why this unwarranted focus on modern putrefactive bacteria?
Why is this "unwarranted"? It was Tedd who brought up the example of
"putrefactive bacteria".
TH>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 they have "evolved" why assume they still do what they did 3.9 billion
years ago?
TH>If amino acids were as common then as they are now, they'd
>very likely be metabolized by bacteria.
Is there any hard evidence for this though? I have a book on microbiology
which doesn't say anything about bacteria eating amino acids and nucleic
acids. It does says however that bacteria only move towards food in
response to certain types of chemical stimuli (called "chemotaxis"):
"One advantage of motility is that it enables a bacterium to move
toward a favorable environment or away from an adverse one. The
movement of a bacterium toward or away from a particular
stimulus is called taxis. Such stimuli include chemicals (chemotaxis)
and light (phototaxis). Motile bacteria contain receptors in Various
locations, such as in or just under the cell wall. These receptors
pick up chemical stimuli, such as oxygen, ribose, and galactose. In
response to the stimuli, information is passed to the flagella. If the
chemotactic signal is positive, called an attractant, the bacteria
move toward the stimulus with many runs and few tumbles. If the
chemotactic signal is negative, called a repellent, the frequency of
tumbles increases as the bacterium moves away from the stimulus."
(Tortora G.J., Funke B.R. & Case C.L., "Microbiology: An
Introduction," 1995, p.75).
I would have thought it unlikely they would be stimulated by raw amino
acids and nucleic acids because they would be constantly getting false
signals from their own bodies!
>SJ>If "putrefactive bacteria are anerobic" how do they live in the
>>gut which has air in it?
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.
>>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.
>SJ>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 of "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?
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.
TH>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.
Again, I would need evidence that modern day bacteria are attracted to raw
D-amino acids. They could get all their D-amino acids from existing cell
walls they eat.
If they were attracted to D-amino acids alone they would be confused by
the D-amino acids in their own or other bacteria or even their host's cell
walls.
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?
I would consider this unlikely because of the ready supply of cellular
materials they can already exploit.
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.
>>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. As on so many occasions,
palaeontology has again failed to substantiate evolutionary
presumptions. Considering the way the prebiotic soup is referred to
in so many discussions of the origin of life as an already established
reality, it comes as something of a shock to realize that there is
absolutely no positive evidence for its existence." (Denton M.J.,
"Evolution: A Theory in Crisis," 1985, p.260)
[...]
>>SJ>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.
>SJ>My understanding is that "the common cold" is actually a syndrome
>>of about *200* different strains of virii:
[...]
TH>Probably more than 200; that would assume that you need only
>catch cold 200 times and then you're home free.
Not necessarily. Having been infected by a particular strain of virus and
one's immune system having learnt to recognise it and overcome it, does
not mean one is not going to be infected by the same virus again. Only the
time between infection and recovery is usually shorter in subsequent
infections.
TH>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*.
No. Its not difficult. It is just not worth the cost of vaccinating people
every year for the common cold, considering: a) the number of different
virii, and 2) the relative mildness of the symptoms. The influenza virii are
from the same family as the common cold but they are less numerous and
more severe, so it is worth vaccinating high risk groups like the elderly for
influenza which they actually do (here in Australia at least).
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.
>>TH>I guess we ought to give up know and just conclude God created
>>>Viral Rhinitis to make life difficult for us? :)
>SJ>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.
TH>Why not just engineer an antibody that can mutate right along
>with a virus? Simple right?
Maybe they will in the future?
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.
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
"More than 30 years of experimentation on the origin of life in the
fields of chemical and molecular evolution have led to a better
perception of the immensity of the problem of the origin of life on
Earth rather than to its solution. At present all discussions on
principal theories and experiments in the field either end in
stalemate or in a confession of ignorance. New lines of thinking and
experimentation must be tried...The flow sheet shown in Figure 2 is
a scheme of ignorance. Without fundamentally new insights in
evolutionary processes, perhaps involving new modes of thinking,
this ignorance is likely to persist. (Dose K., "The Origin of Life:
More Questions Than Answers", Interdisciplinary Science Reviews,
Vol. 13, No. 4, 1988, p355)" (Dose K., "The Origin of Life: More
Questions Than Answers", Interdisciplinary Science Reviews, Vol.
13, No. 4, 1988, pp.348,355).
Note "New lines of thinking" and "new modes of thinking" are needed.
There is one "mode of thinking" they all reject out-of-hand, namely
intelligent design! If in fact intelligent design was how the origin of life
happened, then they are doomed to frustration forever trying to find out
how it happened by unintelligent natural processes.
>TH>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*:
[...]
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.
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.
TH>http://ool.weizmann.ac.il/publications.html
Reading a number of "publications" may not be "a simple request".
Unfortunately, as the lateness of this post indicates, I just don't have the
time to look it up. If Tedd thinks it is important to his case, why doesn't he
post what he thinks is relevant so we can all see and debate it?
TH>If you can't do that, I'll assume that the problem is that
>we *don't know enough to rule it out*.
No. *My* problem is time. I have two lab write-ups and one major
assignment to do and I am late already answering all these emails!
Tedd can look up his own URLs and post from them if he likes.
[...]
Steve
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"`It is often said that all the conditions for the first production of a living
organism are now present, which could ever have been present. But if (and
oh! what a big if!) we could conceive in some warm little pond, with all
sorts of ammonia and phosphoric salts, lights, heat, electricity, etc. present,
that a protein compound was chemically formed ready to undergo still
more complex changes, at the present day such matter would be instantly
devoured or absorbed, which would not have been the case before living
creatures were formed.' (Darwin C.R., letter 1871 to Joseph Hooker, in
Darwin F., ed, "The Life and Letters of Charles Darwin," John Murray:
London, 1888, Vol. 3, p.18). This quote is often reproduced in texts and
articles on the origin of life. Many workers would prefer to replace the
word "protein" with "nucleic acid," as we have seen. Otherwise, it is
remarkably current today, which is a tribute either to his foresight or to our
lack of progress." (Shapiro R., "Origins: A Skeptic's Guide to the Origin of
Life," Summit: New York NY, 1986, p.185)
Stephen E. Jones | sejones@iinet.net.au | http://www.iinet.net.au/~sejones
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