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Prebiotic Soup--Revisiting the Miller Experiment [biogenesis]
Science Magazine ^ | May 2003 | Jeffrey L. Bada and Antonio Lazcano

Posted on 11/02/2003 10:30:46 AM PST by PatrickHenry

"Isn't life wonderful?" sang Alma Cogan and Les Howard in their almost forgotten 1953 hit. That same year, Stanley L. Miller raised the hopes of understanding the origin of life when on 15 May, Science published his paper on the synthesis of amino acids under conditions that simulated primitive Earth's atmosphere (1). Miller had applied an electric discharge to a mixture of CH4, NH3, H2O, and H2--believed at the time to be the atmospheric composition of early Earth. Surprisingly, the products were not a random mixture of organic molecules, but rather a relatively small number of biochemically significant compounds such as amino acids, hydroxy acids, and urea. With the publication of these dramatic results, the modern era in the study of the origin of life began.

Since the late 19th century, the belief in a natural origin of life had become widespread. It was generally accepted that life's defining properties could be understood through physico-chemical characterization of "protoplasm," a term used to describe the viscous translucent colloid found in all living cells (2). Expressions like "primordial protoplasmic globules" were used not only by scientists but also in fiction, from Gilbert and Sullivan's Pooh-Bah in The Mikado (1885) to Thomas Mann's somber imaginary character Adrian Leverkühn in Doktor Faustus (1947). But few dared to be explicit, even in novels. Questioned about the origin of life, a chemist in Dorothy L. Sayers' novel The Documents in the Case (1930) states that "it appears possible that there was an evolution from inorganic or organic through the colloids. We can't say much more, and we haven't--so far--succeeded in producing it in the laboratory."

Some were willing to fill in the details. At the turn of the 20th century, many scientists favored the idea of primordial beings endowed with a plant-like (autotrophic) metabolism that would allow them to use CO2 as their source of cellular carbon. However, some scientists--including A. I. Oparin, J. B. S. Haldane, C. B. Lipman, and R. B. Harvey--had different ideas (3). The most successful and best-known proposal was that by Oparin, who, from a Darwinian analysis, proposed a series of events from the synthesis and accumulation of organic compounds to primordial life forms whose maintenance and reproduction depended on external sources of reduced carbon.

The assumption of an abiotic origin of organic compounds rested on firm grounds. In 1828, F. Wöhler had reported the first chemical synthesis of a simple organic molecule (urea) from inorganic starting materials (silver cyanate and ammonium chloride).

After a large body of research on the synthesis of simple organic compounds accumulated in the 19th century (see figure above), W. Löb achieved the chemical syntheses of simple amino acids such as glycine by exposing wet formamide to a silent electrical discharge and to ultraviolet light (4).

These efforts to produce simple organic compounds from simple reagents heralded the dawn of prebiotic organic chemistry. However, there is no indication that the scientists who carried out these studies were interested in how life began on Earth, or in the synthesis of organic compounds under possible prebiotic conditions. This is not surprising, because the abiotic synthesis of organic compounds was not considered to be a necessary prerequisite for the emergence of life.

From the 1950s, chemists were drawn toward the origin of life. Driven by his interest in evolutionary biology, Melvin Calvin tried to simulate the synthesis of organic compounds under primitive Earth conditions with high-energy radiation sources. He and his group had limited success: the irradiation of CO2 solutions with the Crocker Laboratory's 60-inch cyclotron led only to formic acid, albeit in fairly high yields (5). Miller's publication 2 years later showed how compounds of biochemical importance could be produced in high yields from a mixture of reduced gases.

The origin of Miller's experiment can be traced to 1950, when Nobel laureate Harold C. Urey, who had studied the origin of the solar system and the chemical events associated with this process, began to consider the emergence of life in the context of his proposal of a highly reducing terrestrial atmosphere. Urey presented his ideas in a lecture at the University of Chicago in 1951, followed by the publication of a paper on Earth's primitive atmosphere in the Proceedings of the National Academy of Sciences(6).

Almost a year and a half after Urey's lecture, Miller, a graduate student in the Chemistry Department who had been in the audience, approached Urey about the possibility of doing a prebiotic synthesis experiment using a reducing gas mixture. After overcoming Urey's initial resistance, they designed three apparatuses meant to simulate the ocean-atmosphere system on primitive Earth (3). The first experiment used water vapor produced by heating to simulate evaporation from the oceans; as it mixed with methane, ammonia, and hydrogen, it mimicked a water vapor-saturated primitive atmosphere, which was then subjected to an electric discharge (see the figure below). The second experiment used a higher pressure, which generated a hot water mist similar to that of a water vapor-rich volcanic eruption into the atmosphere, whereas the third used a so-called silent discharge instead of a spark.

Miller began the experiments in the fall of 1952. By comparison with contemporary analytical tools, the paper chromatography method available at the time was crude. Still, after only 2 days of sparking the gaseous mixture, Miller detected glycine in the flask containing water. When he repeated the experiment, this time sparking the mixture for a week, the inside of the sparking flask soon became coated with an oily material and the water turned a yellow-brown color. Chromatographic analysis of the water flask yielded an intense glycine spot; several other amino acids were also detected. Experiments with the second apparatus produced a similar distribution and quantities of amino acids and other organic compounds, whereas the third apparatus with silent discharge showed lower overall yields and much fewer amino acids (primarily sarcosine and glycine).

After Miller showed the impressive results to Urey, they decided to submit them to Science. Urey declined Miller's offer to coauthor the report because otherwise Miller would receive little or no credit. Knowing that a graduate student could have a difficult time getting a paper like this published, Urey contacted the Science editorial office to explain the importance of the work and ask that the paper be published as soon as possible. Urey kept mentioning the results in his lectures, drawing considerable attention from the news media.

The manuscript was sent to Science in early February of 1953. Several weeks went by with no news. Growing impatient, Urey wrote to Howard Meyerhoff, chairman of AAAS's Editorial Board, on 27 February to complain about the lack of progress (7). Then, on 8 March 1953, the New York Times reported in a short article entitled, "Looking Back Two Billion Years" that W. M. MacNevin and his associates at Ohio State University had performed several experiments simulating the primitive Earth--including a discharge experiment with methane wherein "resinous solids too complex for analysis" were produced. The next day, Miller sent Urey a copy of the clipping with a note saying "I am not sure what should be done now, since their work is, in essence, my thesis. As of today, I have not received the proof from Science, and in the letter that was sent to you, Meyerhoff said that he had sent my note for review."

Infuriated by this news, Urey had Miller withdraw the paper and submit it to the Journal of the American Chemical Society. Ironically, at the same time (11 March), Meyerhoff, evidently frustrated by Urey's actions, wrote to Miller that he wanted to publish the manuscript as a lead article and that he wanted Miller--not Urey--to make the final decision about the manuscript. Miller immediately accepted Meyerhoff's offer, the paper was withdrawn from the Journal of the American Chemical Society and returned to Science, and was published on 15 May 1953.

On 15 December 1952, well before the Miller paper was sent to Science, K. Wilde and co-workers had submitted a paper on the attempted electric arc synthesis of organic compounds using CO2 and water to the same journal. They reported that no interesting reduction products, such as formaldehyde, were synthesized above the part-per-million level. This result supported the surmise of Miller and Urey that reducing conditions were needed for effective organic syntheses to take place. Surprisingly, when the paper by Wilde et al. was published in Science on 10 July 1953, it did not mention Miller's paper, although the authors did note that their results had "implications with respect to the origin of living matter on earth."

Miller's paper was published only a few weeks after Watson and Crick reported their DNA double-helix model in Nature. The link between the two nascent fields began to develop a few years later, when Juan Oró demonstrated the remarkable ease by which adenine, one of the nucleobases in DNA and RNA, could be produced through the oligomerization of hydrogen cyanide (8). It would eventually culminate in the independent suggestions of an "RNA world" by Carl Woese, Leslie Orgel, and Francis Crick in the late 1960s and by Walter Gilbert in 1986.

The impact of the Miller paper was not limited to academic circles. The results captured the imagination of the public, who were intrigued by the use of electric discharges to form the prebiotic soup. Fascination with the effects of electricity and spark discharges on biological systems started with the work of L. Galvani in 1780 with frog legs and the discovery of "animal electricity." And an everlasting impression was left in the public's imagination by Mary W. Shelley's Frankenstein (1818), in which Eramus Darwin gained a place for his advocacy of therapies based on electric discharges.

Although in 1953, few envisioned the possibility of Frankenstein monsters crawling out of Miller's laboratory vessels, the public's imagination was captivated by the outcome of the experiment. By the time that the results were corroborated by an independent group 3 years later (9), the metaphor of the "prebiotic soup" had found its way into comic strips, cartoons, movies, and novels, and continues to do so. In Harry Mulisch's novel The Procedure (1998), one of the central characters encounters disaster while paving his way to the glittering halls of Stockholm for achieving the artificial synthesis of life from a primitive soup.

But is the "prebiotic soup" theory a reasonable explanation for the emergence of life? Contemporary geoscientists tend to doubt that the primitive atmosphere had the highly reducing composition used by Miller in 1953. Many have suggested that the organic compounds needed for the origin of life may have originated from extraterrestrial sources such as meteorites. However, there is evidence that amino acids and other biochemical monomers found in meteorites were synthesized in parent bodies by reactions similar to those in the Miller experiment. Localized reducing environments may have existed on primitive Earth, especially near volcanic plumes, where electric discharges (10) may have driven prebiotic synthesis.

In the early 1950s, several groups were attempting organic synthesis under primitive conditions. But it was the Miller experiment, placed in the Darwinian perspective provided by Oparin's ideas and deeply rooted in the 19th-century tradition of synthetic organic chemistry, that almost overnight transformed the study of the origin of life into a respectable field of inquiry.

[Illustrations and footnotes in the original.]


TOPICS: Culture/Society; Miscellaneous; Philosophy
KEYWORDS: abiogenesis; biogenesis; crevolist; earlyearth; evolution; millerexperiment; originoflife
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To: donh
True, we don't know the exact numerology--but with each variable we uncover, it seems to add more and more exponents to the unlikliness that life was automatic (for the reasons I listed to you before and many, many others).

Don't you think we should base our beliefs on the most probable? Yes, there is a chance that liberal ideas (say affirmative action) will work--and we all acknowledge the chance. However, the evidence surrounding those ideas proves that chance unlikely to be successful, and therefore conservatives (at least on non-moral issues) will not support it.
201 posted on 11/06/2003 1:00:55 PM PST by Loc123
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To: Loc123
201?
202 posted on 11/06/2003 1:04:55 PM PST by js1138
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To: Loc123
However, my main point is still unaddressed (as you honestly admitted). Why did only 1 type receive this ability in a racemic mixture given the conditions I layed out? You say it "did have to be" one of the two, but there is no reasoning for this, given the relatively infinite amounts of energy and resources being given to earth at that time (if that weren't the case then NO complex molecules would be able to form for thermodynamic/entropic reasons).

It's extremely improbable that a coin properly flung would come to rest standing unsupported on its edge, despite the utterly equal probabilities before the fact of heads versus tails. After the fact, it was one thing and not the other.

The L- stuff and the D- stuff are generated together, physically mixed together, but don't mix chemically. They exist in sort of parallel, mirror image worlds--for a time. However, the chemical interactions these forms do have are chaotic, the kind of thing that gets hard to model even with a supercomputer after a time. The "parallel" sides will not stay in perfect mirror-image step, with or without the weak force making enantiomers of one particular handedness a bit more stable.

203 posted on 11/06/2003 1:09:07 PM PST by VadeRetro
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To: Loc123
I'll make it simple. Flip two coins in parallel. Every time you flip one, you flip the other. Keep a score for both. Every heads is +1. Every tails is -1.

After fifty flips each, both will total zero, right? Probably not. Nor will those totals with any more likelihood equal each other. That's a chaotic process. No bias, just chaos.

204 posted on 11/06/2003 1:57:04 PM PST by VadeRetro
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To: Loc123
True, we don't know the exact numerology--but with each variable we uncover, it seems to add more and more exponents to the unlikliness that life was automatic (for the reasons I listed to you before and many, many others).

Well, no. If you want to calculate the odds of something happening, you need to specify a state space, and a selection criteria, and then do the math. The selection criteria you are implying is that cellular life leaped into existence and the state space is Miller's pond full of amino acids, with no intermediate stable state spaces to be considered.

What you have here is a just-so story of low believability, not a reasonable basis for a calculation of odds by a statistician. Where is your evidence that there weren't a multitude of intermediate state-spaces between cellular life and Miller's pond where the odds were really pretty good?

Don't you think we should base our beliefs on the most probable?

Only when you can construct a state-space and selection criteria that you can defend in court, will you have the least notion of how probable one or another event might be.

205 posted on 11/06/2003 2:55:11 PM PST by donh (1)
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P L A C E M A R K E R
206 posted on 11/06/2003 6:45:55 PM PST by PatrickHenry
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To: VadeRetro
I appreciate your analogy, however it doesn't apply to this system. In the early Earth--as I have said numerous times--there was relatively infinite energy (relative to the magical self-replicating molecules). Therefore, there was no selective pressure on those molecules to compete.

The only time I could see some selective pressure on the two species would be after they left their nutritious birth envirnment. In either case, we cannot say which had an advantage because, while lower energy is usually preferrable, a higher energy molecule has the advantage of allowing for decreased entropy (the tenent of life) as well as a preferrable receptor/donor for larger energy chemicals (be it polar, ionic, etc).

Most importantly, I just don't see the pressure to select a species given the necessary high-energy bombardment then-present.
207 posted on 11/07/2003 3:43:09 PM PST by Loc123
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To: donh
I am not. I am accounting for non-life form polymerization when I reminded you (in an earlier post) that dehydration polymerization would be impossible in a aqeuous environment (Ie the smokestacks). I also mentioned but a few prospects that have been, so far, dead-end points for abiogenesis. They are in my previous posts to you.

Of course I don't have the exact variable quantities, all of the damaging and supportive variables for abiogenesis, and a perfect model of the primeval (sp?) Earth.

If I did have such proof against abiogenesis, I would be in the top ten for scientists and would also erase the religious tenant of faith in this universe--because who would deny absolute proof of a Creator and therefore follow His Truth?
208 posted on 11/07/2003 3:48:27 PM PST by Loc123
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To: Loc123
I appreciate your analogy, however it doesn't apply to this system. In the early Earth--as I have said numerous times--there was relatively infinite energy (relative to the magical self-replicating molecules). Therefore, there was no selective pressure on those molecules to compete.

You seem to be pulling difficulties out of nowhere here. Is there some reason I'm wasting my time, that you're absolutely positively never going to accept a mechanistic, chemical, non-magical version of where life comes from? This is getting very lame.

The molecules don't know they're in a competion. It just happens that the first self-replicator is going to inherit the Earth, but nothing on Earth actually knows that. The energy available at any time isn't infinite, and infinite energy would be bad for organic synthesis anyway.

Selective pressures only start after you get imperfect self-replicators making various strains of some original. Then natural selection has something to select. Classic Darwinian evolution begins. Before then it's pretty much blind chemical dumb luck.

209 posted on 11/07/2003 4:30:14 PM PST by VadeRetro
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To: VadeRetro
VadreRetro,

If you present a compelling argument, I will cede the point. Unfortunately, you seem to not have familiarity with chemistry/physics as it relates to endothermic chemicals.

Why would the first self-replicating molecule inherent the Earth?

The energy available at the time is RELATIVELY infinite--notice I noted that term many times for a purpose. If the proscribed environment was the smokestacks, then the energy would be relatively infinite.

Then you say that infinite energy would be bad for organic synth--but without extremely high energies organic synth from non-organic structures would be impossible. This is basic entropy/energy transaction. To create a self-replicating, polymerized, normally unstable configuration of chemicals--all of which describe organic chemicals--you need huge amounts of activation energy or endothermic energy. Without this "pressure" organic molecules that could ever self-replicate would simply bind with inorganic cations, transition metals, or lower energy organic atoms (which have no possibility of self-replication since they are in their lowest energy state).

And how would self-replicators--ideally set for a specific bond, manage to selectively evolve? Basic thermochem shows that it takes enormous external energies to synth larger chemicals. Therefore, the "self-replicators" would likely be small and only slightly endothermic. I don't think there is a hypothetical mechanism yet that would explain why or how they would form relatively (to the first "replicators") complex molecules.

And on the selective pressurs--this is a catch-22 for early replicators. If they (both species or a single, it doesn't matter), had huge amounts of energy and building blocks available, then there would never be any selective pressure. And if the species(es) had suddenly an environment deprived of energy/building block, then they would all decompose due to the inability to bond with the other different (imperfect) self-replicators that had simultaneously utilized the remaining energy/building blocks.

I'm sorry you are getting frustrated, but chemistry is a very precise science--it is not like politics where you can quote an authority and assume credibility unless that authority accounts for inadequecies in his model. In that doctor's model--from what I read and what you posted--there are no proposed solutions to these objections.

Likewise, it appears to me that our increasing knowledge about early Earth chemistry and the nature of life and its precursors (if any) increasing point to the need for an intelligent Agent.
210 posted on 11/07/2003 4:49:07 PM PST by Loc123
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To: Loc123
If you present a compelling argument, I will cede the point. Unfortunately, you seem to not have familiarity with chemistry/physics as it relates to endothermic chemicals.

You've been clueless as a newborn babe and bludgeoning with ignorance.

Why would the first self-replicating molecule inherent the Earth?

Do you imagine that any lurker following this conversation shares your puzzlement on this point? The first self-replicating molecule floats in a sea of "food." It is the only eater on Earth. That's a sophisticated point you just had me explain, there! I'm sure dozens of people are glad you helped clear up their puzzlement on such a stumper.

The energy available at the time is RELATIVELY infinite--notice I noted that term many times for a purpose.

"RELATIVELY infinite." Why didn't I guess? There's some dynamic equilibrium in which the Earth is losing almost the same amount every day as the sun pours in. It's mostly solar, with some geothermal. The geothermal is higher than current levels because there's more uncooked uranium (about twice as much) and more residual heat from the formation of the Earth. The sun, OTOH, is thought to have been rather dimmer back then. Anyway, there's a finite available energy.

And how would self-replicators--ideally set for a specific bond, manage to selectively evolve? Basic thermochem shows that it takes enormous external energies to synth larger chemicals.

All you need is time and stable sub-assemblies. You don't know what you're talking about. Nothing jumps together all at once. Read the main article on this thread. Miller type experiments showed that simple carbon, hydrogen, nitrogen, and oxygen molecules combine and recombine in utterly chaotic ways over time. It's the same ambient energy for all the reactions.

I'm sorry you are getting frustrated, but chemistry is a very precise science ...

I use chaotic here in the sense of "deterministic but intractable to analysis." Simple dynamics is very precise, but predicting the outcome of a sufficiently vigorous coin toss is almost impossible. You can model as precisely as you want, but if your input model says you will apply a force of one newton but your apparatus applies 1.0001 newton, if your model says the coin is perfectly round but there are small irregularities on the rim of the real thing, you're back to 50-50. The chemistry is the same.

And on the selective pressurs--this is a catch-22 for early replicators.

The selective pressures work the same as now. More viable (sturdier) is good. More fertile (likely to copy successfuly) is good. More adapted to current conditions (food supply, etc.) is good. You have not made the case for any different assumption.

211 posted on 11/07/2003 5:21:49 PM PST by VadeRetro
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To: Loc123
If you present a compelling argument, I will cede the point.

I'm pretty sure the gimmick here is "compelling."

I have more respect for the people who tell me that their religion excludes material explanations for certain things and no amount of evidence is going to change that. They're at least honest.

212 posted on 11/07/2003 5:23:50 PM PST by VadeRetro
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To: Loc123
The only time I could see some selective pressure on the two species would be after they left their nutritious birth envirnment. In either case, we cannot say which had an advantage because, while lower energy is usually preferrable, a higher energy molecule has the advantage of allowing for decreased entropy (the tenent of life) as well as a preferrable receptor/donor for larger energy chemicals (be it polar, ionic, etc).

Despite the fact that you have occasionally thrown out some scientific terms, your overall erudition is so poor that I can't really tell whether your "two species" above refer to the two handednesses "competing" in parallel (quite unconsciously) to develop self-replication, or perhaps you mean two competing strains of self-replicator molecule after the first such has mutated. Isomers of bio molecules are formed, not born. However it may beggar belief, your reference to energy levels points to MacDermott's chirality/weak-force theory and thus would tend to mean your "species" are enantiomers. I'll try to address one point: lower energy isn't "preferable," it's simply a more stable condition.

In short, your objections, never all that plausible, have become very hard to decipher. I'm really getting a sense I'm wasting my time here.

213 posted on 11/07/2003 6:12:33 PM PST by VadeRetro
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To: VadeRetro
I'm really getting a sense I'm wasting my time here.

The A team is busy at another website, and isn't helping as much as they could.

214 posted on 11/07/2003 6:18:19 PM PST by PatrickHenry (Everything good that I have done, I have done at the command of my voices.)
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To: PatrickHenry
The Muttly Team has been staying away from this obviously serious thread...but it's making me too hungry to resist !

SOUP !

Can Muttly have ham-hock and peas in his Prebiotic soup...pleeaaaassseee ?...

OK. Sorry. I just had to do it.

Why do you think they call it Muttly ?

(really sorry. Muttly go away now. Promise)
215 posted on 11/07/2003 6:29:15 PM PST by PoorMuttly ("You cannot be a victim and a hero." - Hon. Clarence Thomas)
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To: PatrickHenry
The A team is busy at another website, and isn't helping as much as they could.

Actually, goodseedhomeschool had her problems with the science stuff even with Dr. Hovind helping her. (OK, that was mean! Dropping to the floor and doing twenty pushups in my daydreams.)

216 posted on 11/07/2003 6:35:34 PM PST by VadeRetro
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To: VadeRetro
VadeRetro says: "Do you imagine that any lurker following this conversation shares your puzzlement on this point? The first self-replicating molecule floats in a sea of "food." It is the only eater on Earth. That's a sophisticated point you just had me explain, there! I'm sure dozens of people are glad you helped clear up their puzzlement on such a stumper."

You still don't understand. It is a complete faith (and an unfounded one) that only a single molecule next to millions would be endowed with self-replication. What process in nature--or even science--is so selective? We cannot yet even isolate a single atom with a laser emmitting a beam a fraction of the atom's size without affecting another atom.

It really is a "stumper" that a single molecule could attain self-replication while being right next to millions of other molecules experiencing the same conditions.

On "infinite energy"--I was referring to the system in which the hypothetical self-replicator inhabits. This system is must be constantly supplied with energies way out of porportion to the energies require by the self-replicator's in order to facilitate the self-replication (IE and prevent valence shell collapse through non self-replicating bonding).


VadeRetro says: All you need is time and stable sub-assemblies. You don't know what you're talking about. Nothing jumps together all at once. Read the main article on this thread. Miller type experiments showed that simple carbon, hydrogen, nitrogen, and oxygen molecules combine and recombine in utterly chaotic ways over time. It's the same ambient energy for all the reactions.

I am aware of the fact that simple molecules have stable bond energies. I was contending your hypothesis that variations of what must be relatively large (to those simple organic molecues) would be changing randomly, with the most efficient ones being selected.

My other main point--which you have completely ignored--is that large organic molecules could not have formed in a primeval system due to my catch-22 scenario--also which you have completely ignored.

Another point: basic thermochem also demands that energy be transferred to and from some system. If energy is transfered to the molecules it would inhibit or even break bonding of large molecules (the energy would be absorbed in bonds able to handle the increase, if it could at all). If energy is somehow transferred away from the molecules, IE when forming large bonds (the almost unanimous way to form larger bonds--through exothermic reactions), then the surroundings would need to increase in energy--which is very difficult given the enormous energies present in the system's surroundings.

In short, it would take VERY precise calibrationS at different times to synthesize large, endothermic molecules. IE an Intelligence.

Your "intractable" point: yes, you are right about precise measurements. But making a simplified model that incorporates known variables and behaviors does not required precise measurements. All I have done is to point out the impossibilities in the abiogenesis theoretical model for Earth (due to chirality, but increasingly for other factors).

You say the selective pressures are the same now--I'm sorry, they are certainly not. As I have said before, there were huge amounts of resources and energy available to the pre-replicators. As long as those two factors remain relatively plentiful, no selection takes place. This leads to my catch-22 point.

My point about species was regarding chirality. And I already directly addressed the points about bond stability--please refute what I said before repeating that argument.

Look, VadeRetro, I'm sorry if you cannot simply reference some scientists generalizations and convince me of your faith. That is what I mean by "compelling." I need to see the model of abiogenesis work; I cannot simply trust generalizations that have gaping holes that seem to expand the more we learn.

If you are becoming frustrated and unpleasant to your family due to me, maybe you should cease the debate. But do know I consider your points and evidence very closely and try to include them in my model (compilation of all variables and physics). It is when the oversimplified model's problems are not resolved or are, in fact, compounded, that I raise the objections. But I am more than willing to continue this discussion--even if you see the need to make it ad hominem (and without good proof).

217 posted on 11/07/2003 6:49:17 PM PST by Loc123
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To: Loc123
And how would self-replicators--ideally set for a specific bond, manage to selectively evolve? Basic thermochem shows that it takes enormous external energies to synth larger chemicals.

Here's just another case in which I can't tell when you're talking about before the self-replicator exists and when after. The first sentence ("And how would self-replicators--ideally set for a specific bond, manage to selectively evolve?") seems to presume as a given that the self-replicator has formed, the question for the moment being how such would evolve different strains.

The answer, then as now, is imperfect replication. Get one strain, soon you will have several. Most of the "bad" copies do not possess the self-replicating attribute of their parent and "die" (are eventually destroyed) without having ever reproduced. A few here and there, however, are more stable ("healthy") or more "fertile" in reproducing and will give the parent strain a run for its money. This is a Darwinian scenario, competition for resources.

Your second sentence ("Basic thermochem shows that it takes enormous external energies to synth larger chemicals") seems to refer to the difficulties of forming a complex molecule, the replicator, in the first place. (I've dealt with the objection it contains, which is just wrong, and won't repeat that here.) The effect of the two sentences in the order given is to cast confusion upon what part of the scenario is even being questioned. Then you have the business of calling L- and D- isomers "species," which also obscures whether the time before or after Replication Day is meant. I have endeavored to make clear that the formation of that first replicator is a very sharp dividing line. It is the end of random dumb luck and the start of real evolution.

218 posted on 11/07/2003 7:01:24 PM PST by VadeRetro
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To: Loc123
You still don't understand. It is a complete faith (and an unfounded one) that only a single molecule next to millions would be endowed with self-replication.

Nothing forbids. It's Murphy's Law in reverse. Whatever can happen, will happen. There's time and a nice warm soup. You not only haven't made a credible objection, you haven't made a comprehensible objection.

It really is a "stumper" that a single molecule could attain self-replication while being right next to millions of other molecules experiencing the same conditions.

Somebody says the magic word. Down comes the duck with the 100 dollars. The band plays "Captain Spaulding."

My other main point--which you have completely ignored--is that large organic molecules could not have formed in a primeval system due to my catch-22 scenario--also which you have completely ignored.

There may be a few Catch-22s in nature, but they may not be the same as your imaginings. You have not done a good job explaining why anything is impossible here. I hope I've made clear in the preceding posts just how vague, rambling, and unscientific your objections have been. That's not the same as ignoring them.

Another point: basic thermochem also demands that energy be transferred to and from some system. If energy is transfered to the molecules it would inhibit or even break bonding of large molecules (the energy would be absorbed in bonds able to handle the increase, if it could at all). If energy is somehow transferred away from the molecules, IE when forming large bonds (the almost unanimous way to form larger bonds--through exothermic reactions), then the surroundings would need to increase in energy--which is very difficult given the enormous energies present in the system's surroundings.

To the extent I understand this, the Miller experiment itself already refutes it. Synthesis of more complex molecules continues happens in chaotic, mostly unpredictable ways. There is no complexity barrier. The ambient energy levels are fine for the continuous recombination, billions of parallel experiments every second for millenium after millenium.

I need to see the model of abiogenesis work; I cannot simply trust generalizations that have gaping holes that seem to expand the more we learn.

The tasking here has moved quite a bit, from "Explain the handedness of bio molecules" to "Cook me up a cell in a test tube." I consider the goalposts moved. If you have nothing better, we're done.

219 posted on 11/07/2003 7:14:45 PM PST by VadeRetro
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To: VadeRetro
VadeRetro says: "Nothing forbids. It's Murphy's Law in reverse. Whatever can happen, will happen. There's time and a nice warm soup. You not only haven't made a credible objection, you haven't made a comprehensible objection."

If you truly believe that "something" annoted one molecule next to millions with a special gift--and that gift had no effect on its identical (or nearly so in some cases), then you believe in a Creator. Congratulations.

VadeRetro says: Somebody says the magic word. Down comes the duck with the 100 dollars. The band plays "Captain Spaulding.

right.......

VadeRetro says: "There may be a few Catch-22s in nature, but they may not be the same as your imaginings. You have not done a good job explaining why anything is impossible here. I hope I've made clear in the preceding posts just how vague, rambling, and unscientific your objections have been. That's not the same as ignoring them.:

Care to refute my "imaginings?" If you cannot analyze my arguments, I guess you then cannot debate this issue.

VadeRetro says: To the extent I understand this, the Miller experiment itself already refutes it. Synthesis of more complex molecules continues happens in chaotic, mostly unpredictable ways. There is no complexity barrier. The ambient energy levels are fine for the continuous recombination, billions of parallel experiments every second for millenium after millenium."

Miller created certain non-polymerized, lower energy amino acids from polymerized precursors. You have not touched any of my objections to the creation of complex or endothermic molecules in the most-likely medeval system. Also, there were not "billions of parallel experiments" because the conditions remained constant as did the majority (if not all for the reasons I outlined) remained constant. This is the basic tenant of science: that an experiment needs a chaning variable.

VadeRetro says: The tasking here has moved quite a bit, from "Explain the handedness of bio molecules" to "Cook me up a cell in a test tube." I consider the goalposts moved. If you have nothing better, we're done.

You could not explain chirality without referencing a Creator (the one that "picked" a single molecule among millions, etc). You then tried to contend why this selective annointation is possible (with faith) and I refuted it with thermochemistry and entropic arguments. So while the scope of the debate changed, the argument at its core remained the same.

I would please ask that you address my actual scientific objections regarding thermochemistry and entropy before we proceed. Overgeneralized and illogical asides are not constructive. Neither are making a big deal about a single word: species (which works as well and was in context).

Though I do appreciate your effort.
220 posted on 11/07/2003 7:54:38 PM PST by Loc123
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