Murchison Meteor Questions

Using acid to extract molecules is not the same as using an acid environment to form the molecules. The extraction method used is essentially irrelevant to the formation of the molecules (or it's not a valid extraction process).The first paper referred to the adenine etc being bound to kerogen-like compounds (the other (unidentified) organics?), and this would be consistent with needing stronger extraction methods:

quote:

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A large unidentified peak in the chromatogram with a retention time of ~ 5 min and showing significant tailing, made it difficult to accurately quantify these nucelobases, especially uracil, in the Murchison formic acid extract.

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The presence of a kerogen-like organic polymer in Murchison may inhibit the sublimation of these nucleobases directly from the meteorite [7].

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It seems to me that the evidence points to adenine being present on the meteor (along with the other 'biological' molecules noted).Enjoy.Edited by RAZD, : end.Edited by RAZD, : added to last quote

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Hi Rob,
You are certainly correct that the implication of the discovery of adenine in meteorites can be overstated. Carbonaceous chondrites are a fairly poor source of organic compounds on the surface of the early Earth. See, for instance,
http://www.springerlink.com/content/d0013w72562v0214/?p=5...
which is a just-published article in Origins of Life and Evolution of Biospheres, and is definitely a paper I have a vested interest in (seeing as I'm the first author ). The abstract should be publicly available, at the very least. Unfortunately, I can't quite give out .pdfs as there are copyright issues.However, as RAZD has explained in part, the extraction of adenine by formic acid and water from Murchison is not equivalent to the formation of adenine in an artificial laboratory setup. Consider the following:Adenine is sparingly soluble in water. In life, adenine is made a factor of 100-1000 times more soluble by the addition of ribose and phosphate. This increases the solubility of adenine as an adenosine nucleotide substantially. Thus water extracts of this material are already fighting an up hill solubility battle.Next, insoluble organic matter/tar is the major carrier of carbon in the Murchison meteorite. This material is quite similar chemically and structurally to adenine, and is bound to mineral particles. Adenine is highly "soluble" in this material. Hence, trying to force it from the insoluble matter into the aqueous phase (e.g., from something it likes being in to something it doesn't like being in) is very difficult. The difficulty in solubility has been compounded by the chemical extraction procedures. Here's a statement from Glavin et al. 2006: However, these results are not equivalent to experiments critiqued by Shapiro and Behe. Formic acid solutions were employed to extract adenine since adenine is a nucleobase, and an acid solution is necessary to fight the compounded difficulty of insolubility in water and solubility in the insoluble organic matter. Adenine is by my quick estimate, a factor of 10^6 more soluble in the formic acid solution than in water alone. It's no wonder that it's hard to spot in the water extracts.Note that the work done on carbonaceous chondrites only proves one thing: That organic compounds of biologic relevance are formed through abiotic processes. These organic compounds are clearly formed through abiotic processes as 1) they have D/H, C13/C12, and N15/N14 ratios consistent with extraterrestrial material and not consistent with terrestrial material, 2) there is not a major handedness to these molecules (both forms are produced in ratios ~50:50, or at most 40:60), and 3) there is a host of decidedly non-biologic organic compounds also detected in extracts.Some origins of life researchers sloppily conclude that meteorites were the ultimate source of these organic compounds. They are wrong. Other extraterrestrial material (interplanetary dust particles, comets) may be a better source, but they've been much less studied, mainly due to lower amounts of samples. The implications from these meteorite studies are primarily that biologic organics can be formed from non-biologic processes. Placed in the greater context of this work, meteorites confirm some of the potentially prebiotic experiments, at least in part.

I appriciate you contribution Matt. And your answer to the problem of adenine being somewhat 'anti-water soluble' (if I can put it that way) makes sense to me.You also touched on something Razd said. I want to ask you about it...The kerogen-like compound (or compounds) that the adenine is supposedly bound with (in the meteor) are said to be explained by the experiment with actual kerogen (or humic acid though they're not exactly the same from what I gather) and pure mixtures of adenine.Is that really an analogous test?My doubt comes from the fact that we do not have as confined a definition of the meteor composites. Though kerogen and humic acid are also not well defined, can we say with reasonable certainty that a sample of this meteor is analogous?You see, we have this conglomerate in the metoer, and these acid extractions are said to be simmilar to the more controlled experiments. But how can we be sure that 'unknown' mineral or elemental influences do not substancially change the reactions. I am not well versed in chemistry, and perhaps that is the only difficulty. But even Glavin and his associates said they could not dismiss the possibility. Could the chemical composition of the meteor alter the sensitivity to temperature durring the oligamerization of HNC?Seems difficult to pin down form what I have read.I hope I am making myself clear...Let me put it this way also... When we use acids to extract a metal from it's ore for instance, we are extracting an actual element from the oxidizer. But atomically, the element is there. In the case of adenine or any other molecule, we are not dealing with an element. So, when we extract something such as adenine, and it is combined with other molecular material (effectively making it another compound altogether), how can we know if it was there to begin with if we do not understand the processes that led to it's current state?If in the process of extraction, we have altered the molecule so as to essentially synthesize it, then we have not discovered adenine. The question is, 'can we be sure in this case'?I don't think so. It appears emperically fuzzy though compelling.MattP:Back to ATP we are...I haven't read your paper yet, but will. In your opinion, has adenine been (in spite of the issue of handedness) conclusively found in the murchison meteor establishing it's existence outside of biological organisms?Hope I asked some intelligent (even if possibly sophomoric) questions.Edited by Rob, : No reason given.

Razd: As to your first comment, that is the question... I'm not so sure yet!I agree with the second part, but it ties into the first.You may want to see my resopnse to MattP in message 18 above. I am asking questions in order to understand it better myself.

JavaMan: Aren't you a clever fellow... Well... just so you know, I think it is quite appropriate in this case. Though I do not think one must be a 'methodological naturalist' to be a believer in empiricism. That's why I am asking the questions that I am...It all started in the last thread. My question was, 'Does anyone have any evidence at all for a pre-biotic organism?'The answer is no!And the reason I did, was because we have a whole planet full of empirical evidence for biological organisms.We are not here to discuss what I think the actual evidence points to. We are here to see whether there is any evidence for you to point to.Do you perceive the difference?And if anyone wants to debate this, take it to another thread. Been there done that! See here: http://EvC Forum: Converting raw energy into biological energy -->EvC Forum: Converting raw energy into biological energyEdited by Rob, : No reason given.Edited by Rob, : No reason given.

The answer is we don't know. Viruses could be (evolved) remnants of pre-cellular replicating mechanism (where do you draw the line on life eh?)The empirical evidence we have from the oldest known rock that could have fossils that we could look at (has not been metamorphized) show life already existing in the form of cyanobacteria very similar to what we know today. This is from rock that is dated to 3.5 billion years old. That means that to find older evidence we need to find either (a) older sedimentary rock or (b) be able to distinguish the product of life processes in metamorphic rock - and there have been some (controversial) attempts at that.The question is - what would the evidence of pre-biotic life look like in the fossil record then? That's an even tougher nut to crack eh? Oh yes, definitely. But we are pursuing that actual evidence through a 'methodological naturalist' approach because it is the most likely to deliver reasonable -- and unbiased -- answers to the question "could this have happened?" The issue is what the acid can and cannot do in these chemical processes. Formic acid is a relatively weak acid IIRC (compared to HCl or H₂SO₄ which are strong acids). See Acid Strength for a discussion of what makes acids strong\weak.If the acid\heat is not strong enough to disrupt the chemical bond of the molecule, then it will extract it, and if this was strong enough to disrupt the bond then we wouldn't be able to find the molecules.Finally there is a difference between a chemical bond and molecules having an "affinity" for co-existence. There are weak electro-chemical attractions between certain molecules that have a polarized shape, similar to the attraction of ion, but that are not of the strength of molecular bonds. Water is such a molecule, and it forms long chains of weakly bonded molecules. What they did was test the hypothesis by using a similar compound and adenine to see if it was possible to inhibit the extraction on anedine (which they now know is in the kerogen), and they were. This means that it is extremely likely it occurred in the meteor composites as well.EnjoyEdited by RAZD, : finished

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Razd: Well that's strange... because viruses cannot evolve or replicate without a complete cell.What is life? I think you nailed it with your description 'replicating mechanism'.We don't want to get into a debate about the definition of life here. For the record, I believe that the proper definition is an autonomous self replicating system. In fact I found that very definition in a scientific paper while searching for info on Murchison. It confirmed my own thoughts on the matter.This was discussed in the parent thread: http://EvC Forum: Converting raw energy into biological energy -->EvC Forum: Converting raw energy into biological energy Kuresu asked the same question in different words. You can then read my response.Razd: That is simply false... adding or subtracting one atom (and it's chemical bond) would change the molecule from one substance into another. And just because an acid is strong enough to oligomerize HCN, doesn't mean it will act on all of the bonds.We must consider concentration as well.This was made perfectly clear in the OP; HLC did not disrupt the bond. They used it because they were unable to find adenine with weak formic acid extraction ...go read their whole paper in the OP.Razd: No! Your not talking aobut 'methodological naturalism' really... your talking about empericism. And empericism I agree with. And the answer to the question, 'could this have happened', keeps flashing before you; 'Not in terms that are biologically relevant'.As MattP showed in his response. These chondrite samples are clearly not terrestrial in terms of chiralty. They only prove that abiotic processes can produce biological compounds that are "not consistent with terrestrial material, 2) there is not a major handedness to these molecules (both forms are produced in ratios ~50:50, or at most 40:60), and 3) there is a host of decidedly non-biologic organic compounds also detected in extracts." ( http://EvC Forum: Murchison Meteor Questions -->EvC Forum: Murchison Meteor Questions )Abiotic compounds (just like in the Miller experiments) are only life-like. And that is why Murchison is so strikingly simmilar to Miller's experiments. Some take it as confirmation of Miller. I take it as confirmation of abiotic compounds being, well... abiotic!And as Ken showed you in a very straightforward post with tremendous citation, the environmental conditions necessary to produce them are also not compatible with life; extreme heat, reducing atmospheres, comet and meteor imapacts, volcanoes, and otherwise immensly harsh and dangerous conditions are all invoked to explain the arrival of life. And those conditions are not even compatible with each other. We need 'one set' of environmental conditions to show a prodution of one compound, and an entirely different set of conditions for the production of another.I think Occam's razor is haunting you... you are simply supporting the production of evidence, not the examination of existing evidence.The evidence is what you are supposed to examine (ie. the actual biological compounds) You're using your 'method' to theorize evidence that does not actually exist. And let's be clear, there is no evidence for self replicating molecules. Molecules must get energy from elsewhere in order to replicate. And in biology, that comes in the form of ATP. There is no self in replication. It is a system. And that is what makes it so complex.Personally there are times when I am tempted to think that life is itself, emminently unnatural. At the very least, living organisms have qualities that are utterly inexpicable in terms that may explain the environment in which they live. So methodological naturalism may be good in for explaining one system, but we cannot assume without invoking metaphysics that it applies to all systems. But that's another matter and topic really. I just wanted to share my opinion.Anyway, thanks for your opinions Razd. Perhaps we can all work on the other questions together.Edited by Rob, : No reason given.Edited by Rob, : No reason given.Edited by Rob, : No reason given.

MattP: Well why then did Glavin make the following comment in his paper: And I am a little cofused as to the temperature... was it 100c or 450c? This is very confusing since different temperatures were used at different times. And appearently some samples were exposed to acids of differring strength twice.Any thoughts or observations are welcome...

Crashfrog: I agree wholeheartedly!
So, do youhave any evidence for prebiotic organisms that dispove the appearence of design in the biotic organisms in light of their de novo appearence? note to admins.. if the discourse between Crash and I get's prickly, please shut him down. I'd really like to keep things civil. Intelligent questions and intelligent answers. I'll just ignore extreme sarcasm.

Huh?If you knew, it would be evidence. The fact is... IF there is evidence, it remains to be seen. And that is equal to no evidence.What we do have evidence for, is whole systems that we call biological organisms. And they defy material explanation.And that's what this is about... where did we get the parts?As for Murchison, I am not conviced that they were found. And the fact that they are racemic, really points to artificial synthesis relative to their biological counterparts.The parts that can be synthesized outside of biology are not even chiral molecules. They are lifelike only. So even if they were found, we still cannot explain the chiral molecules in biology.How do we take 'natural dust' (if you will) that is racemic, and transform it into chiral molecules and put all of the pieces together? The natural cannot explain the unnatural. If nature builds racemic mixtures, what does that tell you about biology that is chiral?

I've been reading this interesting thread and see it as humming along quite well so far as behavior on both sides.Regarding your concerns about Crashfrog his remarks are what afforded the opportunity for you to counter his argument with your own cogent question to him.At this point I see no need of admin action but will continue to monitor so far as behavior relative to all participants.

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For ideological balance on the EvC admin team as a Biblical creationist.

This would require that you too, be civil.On another note, I find it funny that a lot of pro ID (pro-creo) people argue that there is the appearance of design. Stating "appearance" suggests that it's not necessarily actually designed. Looks aren't everything.Well, is there design or isn't there?

I think you may be using the wrong definition of metaphysical when you interpret Lewontin. He doesn't mean hypothetical or supernatural, but that it is intertwined with issues of the nature of reality. He feels that mainstream evolutionary views are insufficiently nuanced, for instance, concerning natural selection he argues that organisms are not passive recipients of environmental pressures because they influence the environment they inhabit.But we really shouldn't get into Lewontin's views. Promoting a single scientist's views as conclusive when opposed by the main body of scientific thought is just the fallacy of argument from authority. If a single scientist has such and such an amount of authority, how much more authority must the consensus of a large body of scientists have?But what I really wanted to do was focus on your assertion that abiogenesis cannot be disproven. This is true, but only in the sense that no scientific theory can be disproven, or proven either. All that science can do is offer evidence in support of a hypothesis, and if that evidence grows strong enough so that a consensus forms around it, then the hypothesis becomes elevated to theory. But even then the theory is tentative and is subject to change and even rejection in the face of new evidence or improved insight. Your singling out abiogenesis for criticism of something that is true of all scientific theories, because you misunderstand the nature of science.So the point you're making is not a specific one against abiogenesis, but a general one against the naturalistic nature of science. By definition, science focuses on the natural. Science investigates the origin of life by natural processes because science investigates all natural phenomena under the assumption that their underlying causes are natural. Your point actually comes down to an argument for including supernatural possibilities within science, but that should be a topic for another thread in the [forum=-11] forum.--Percy

They evolve when they replicate like any other form of life. That they now use existing cells does not mean they were always so restricted, nor does it compare to what it was like before cellular life evolved. There is one (mimi) virus that is bigger and more complex than the simplest cellular life.See http://www.the-scientist.com/news/20040506/01/ (used to have full article available).
and Just a moment...
and http://www.usatoday.com/...ce/2003-11-13-new-life-usat_x.htmBefore an oxygen atmosphere things were different. But in the process of developing an extraction method you would test it for effect on the molecules you would like to extract to make sure you don't change them. If the acid is not strong enough to disrupt the molecular bonds the concentration of the acid is irrelevant in causing disruption of the molecular bonds. They would use increasing strength to disrupt non-molecular bonds until they were able to separate molecules from the kerogen-like substance. I have. "Methodological naturalism" is "empiricalism."BTW: please notice EMPIRE ... EMPIRICAL - similar spelling: see if you can remember the correct spelling (or use a spell check). This error has been pointed out previously (by Percy). Occasional misspellings are no problem, consistent continued error after it has been pointed out is failure to learn. Pre-biotic compounds are pre-biotic compounds regardless of where they come from and regardless of how they came about. Except the article did not really address the actual science involved, but someones misinterpretation of it. That is why I directed comments to RAZD - Building Blocks of Life -- rather than take your topic off on a tangent. There are several examples of molecules that are self-replicating, some mentioned on RAZD - Building Blocks of Life, and more are discovered every year. This is old news, and denial of the evidence does not make it go away. Currently biological systems get their energy through ATP, but that is an evolved system and it does not mean that the original replicating systems did. Energy comes easily from the sun and the environment, so there is a surplus of energy available. It is a matter of getting a system to use it. And probably good for another topic indeed. It's not that we have no evidence but that we do not have evidence from the time period when life developed .. because it is currently inaccessible. As it sits right now (without new finds of older non-metamorphisized sedimentary rock) we are physically unable to find evidence, because it has been destroyed by the metamorphosis process. This is not the same as being evidence that it could not have developed. What it means is that we don't know. They were formed by chemical processes rather than biological, and that is the whole point eh? These molecules do form by chemical processes. They are pre-biotic molecules, formed by chemical processes and readily available for use in the development of life from these basic building blocks.Chirality may be just a matter of chance: 50:50 chance that it is one or the other that got used in the original surviving form of life that developed. Or maybe 1 in 3 chance if you include original life that may have been able to use both spins (but used more energy and resources to do so). What you end up with is a post hoc ergo propter hoc argument regarding what just happened to occur.And there are systems that sort molecules by chirality, so they may have acted as a template for the assembly process in the develpment of life. These too are mentioned on RAZD - Building Blocks of Life. The question is what tangents you want to take your topic off onto, once the issue of finding adenine on the Murchison meteor is settled. Why not? Adenine was found wasn't it? Where did it come from?Enjoy.

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Percy: That would be nice...Percy:You are absolutely correct! And that assuption cannot be proven with evidence. Therefore, your method is not scientific since science is supposed to be about evidence. It is a philsophical assumption repleat with bias.Let the evidence speak...As you said, this response (and your own) belongs in another thread. If, as the lead admin and facilitator of this forum, you will not resort to invoking off topic concepts to refute my own on-topic debate points, I will not respond with off topic responses in order to defend myself.Percy, I very much appriciate your promoting this topic, and for the mysterious lifting of my suspension, but do you have anything to contribute to the discussion on the Murchison extrations?