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Probabilities and the Genesis of Life

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The important thing to keep in mind concerning probabilities and the origin of life is that proteins, and everything else in a living cell, are manufactured by machinery which is controlled by an abstract-representation digital coding system. Proteins not only don’t self-assemble, they cannot self-assemble, because basic chemistry drives the process in the opposite direction.

Once this is taken into consideration all arguments that assert, “But it could have happened by chance,” are rendered ludicrous on their face.

By way of analogy, the basic Darwinian argument for the origin of life goes something like this:

1) Clay occurs naturally.
2) Bricks are made of clay.
3) Therefore, there is some (given enough time) probability that houses made of clay bricks came about by stochastic processes and the chemistry of clay.

This is the way I see it, and so do most people with common sense. Apparently, one needs a Ph.D. in Darwinian Speculation (or sufficient indoctrination in this academic, “scientific” specialty) not to recognize the obvious.

Comments
Mr Frank, The Wiki (English) entry for "Oxygen catastrophe" has a clearer and more detailed image. While I can imagine a link between oxygen levels and a motile, carnivorous lifestyle, just being multicellular could apply to plants as well. On a related note, I wonder if anyone has studied the timing of the endosymbionic events for chloroplasts and mitochondria.Nakashima
December 20, 2009
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lastyear,
That is correct. There’s all manner of things that we cannot rule out. But just because something cannot be ruled out doesn’t mean it has any merit or even makes sense.
Nor does it mean that it doesn't make sense. We cannot make sense of nature, therefore we have no real basis for comparison when comparing nature to super or non natural things. If we don't understand the rule, we cannot rule out the exception.Clive Hayden
December 17, 2009
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#141 Yes - but this diagram on Wikipedia suggested to me that the oxygen content was low until just before the Cambrian - mind you it is in German so maybe I don't understand it!Mark Frank
December 17, 2009
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Mr Frank, If the atmosphere became oxygenated 2.4 billion years ago, and metazoa appeared 600 million years ago, there is still a vast gulf of time not explained by that hypothesis. Somewhere in that gap, life invented and refined the idea of sexual reproduction. Judging by memories of my own teenage years, I am not at all surprised if this took a billion years to figure out! ;)Nakashima
December 17, 2009
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Mr Nakashima & vjtorley, you both might enjoy this article as well: Costanzo G, S Pino, F Ciciriello, & E Di Mauro (2009). The generation of long RNA chains in water. The Journal of Biological Chemistry 284: 33206-33216.
The synthesis of RNA chains from 3?,5?-cAMP and 3?,5?-cGMP was observed. The RNA chains formed in water, at moderate temperatures (40–90 °C), in the absence of enzymes or inorganic catalysts. As determined by RNase analyses, the bonds formed were canonical 3?,5?-phosphodiester bonds. The polymerizations are based on two reactions not previously described: 1) oligomerization of 3?, 5?-cGMP to ?25-nucleotide-long RNA molecules, and of 3?,5?-cAMP to 4- to 8-nucleotide-long molecules. Oligonucleotide A molecules were further extended by reciprocal terminal ligation to yield RNA molecules up to >120 nucleotides long and 2) chain extension by terminal ligation of newly polymerized products of 3?,5?-cGMP on preformed oligonucleotides. The enzyme- and template-independent synthesis of long oligomers in water from prebiotically affordable precursors approaches the concept of spontaneous generation of (pre)genetic information.
Dave Wisker
December 17, 2009
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Clive Hayden
We don’t know what nature is, and cannot rule out super or non natural things.
That is correct. There's all manner of things that we cannot rule out. But just because something cannot be ruled out doesn't mean it has any merit or even makes sense.lastyear
December 17, 2009
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vjtorley, I would like to echo Mr Nakashima's comments and say this discussion has been a pleasure.Dave Wisker
December 17, 2009
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Mr Nakashima, That was a good reference. Tied in with the following article, we can begin to see how tRNAs (which are actually very small)could form from random RNA sequences. This then ties in well with the stereochemical hypothesis for the origin of the genetic code. Nagaswamy U & GE Fox (2003). RNA ligation and the origin of tRNA. Origins of Life and Evolution of the Biosphere 33: 199-209
A straightforward origin of transfer RNA, (tRNA), is difficult to envision because of the apparently complex idiosyncratic interaction between the D-loop and T-loop. Recently, multiple examples of the T-loop structural motif have been identified in ribosomal RNA. These examples show that the long-range interactions between the T-loop and D-loops seen in tRNA are not an essential part of the motif but rather are facilitated by it. Thus, the core T-loop structure could already have existed in a small RNA prior to the emergence of the tRNA. The tRNA might then have arisen by expansion of an RNA that carried the motif. With this idea in mind, Di Giulio’s earlier hypothesis that tRNA evolved by a simple duplication or ligation of a minihelix RNA was re-examined. It is shown that an essentially modern tRNA structure can in fact be generated by the ligation of two 38-nucleotide RNA minihelices of appropriate sequence. Although rare, such sequences occur with sufficient frequency, (1 in 3 × 107), that they could be found in a standard in vitro RNA selection experiment. The results demonstrate that a series of RNA duplications, as previously proposed, can in principal account for the origin of tRNA. More generally, the results point out that RNA ligation can be a powerful driving force for increased complexity in the RNA World.
Dave Wisker
December 17, 2009
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Oramus 115, Joseph 116, vjtorley 133 You are right! I had not thought about the requirement to create an oxygen rich atmosphere to sustain multicellular life. I do disagree with Joseph's line in #116 One doesn’t have to know the motivations to critique the design If you don't know what the design is intended to do - how can you know if it does it well?Mark Frank
December 17, 2009
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lastyear,
There is no utility in trying to compare the natural and the non natural. Simply chalk the concept of the later up to the generous ‘nature’ of language and the creative abilities of the human mind.
Then call it super instead of non natural. It doesn't much matter. We don't know what nature is, and cannot rule out super or non natural things.Clive Hayden
December 16, 2009
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Mr Vjtorley, I respect your exit from the conversation for now, and I hope you do not feel chased by a bear! Enjoy your vacation reading as much as you can! Here is an article that sketches the origin of the RNA World in a way similar to that which I laid out above. I offer it with compliments and a hope you enjoy Christmas and New Years.Nakashima
December 16, 2009
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Upright BiPed, Dave Wisker, Mr. Nakashima, IrynaB and Mark Frank: First of all, Upright BiPed is perfectly correct to point out that my "steps-along-the-road" metaphor fails to adequately convey the real difficulty of undirected abiogenesis. The main reason why I used the "steps along the road" metaphor is that ordinary people (including myself) are psychologically wedded to it. Discuss any outstanding problem at work with your boss, and he/she will ask you when you're on track to finish. And when people read articles in The New York Times suggesting that progress has been made in discovering how life evolved, their natural response is: "Well, how far along the road are we?" The purpose of the "steps" metaphor was to lend a sense of perspective to the issue. We are nowhere close to finding out how life evolved. The "size" metaphor ws intended for the same purpose. People want to know stuff like that, because that's how they think. Ordinary people (including myself) appreciate vivid visual metaphors. Telling people that scientists have made a molecule that's 1,000,000 times smaller than the simplest cell immediately conveys that progress achieved to date has been very limited. That's why popular science magazines pushing abiogenesis never mention these awkward facts. But UprightBiPed hit the nail on the head with his comments. For, as he correctly observes, life is not just a collection of parts, but the intricate coordination of those parts into a function. In other words, the defining feature of life consists in its form, not its matter. Mr. Nakashima acknowledges the same point when he suggests that we need to get past the synthesis of the physical components, and move up to the next level. Nothing we see in the world is totally unstructured. We can speak of a form-matter spectrum, for the sake of convenience. Although it represents a geneuine advance, the foregoing discussion of ribonucleotide synthesis by Sutherland et al., is much closer to the "matter" end of the spectrum than the "form" end, as far as life is concerned. With life, we see layer upon layer of complexity. The rich 3D structure of life is a marvel that we are struggling to explain. When I narrated my story of making a model shark, I remarked that it was very hard to fit the pieces into the right 3D shape. But assembling an RNA molecule would be incomparably more difficult: as I remarked in my previous thread, it has a rich 3D structure. Mark Frank: the reason why the development of metazoans took so long was that it was a much bigger jump, in terms of complexity. You might like to have a look at these pages, which will answer your questions: http://www.darwinsdilemma.org/cambrian-explosion.php http://www.darwinsdilemma.org/pdf/faq.pdf As to the late emergence of animals: maybe the reason was that the early Earth needed to be stabilized first (think of climate systems etc). It has been a pleasure exchanging views with you all. Bye for now.vjtorley
December 16, 2009
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Mung, you said...
If you ask me, everything that exists has a “nature” or “essence” and anything which does have a “nature” or “essence” is therefore, by definition, natural.
So nothing non natural exists.lastyear
December 16, 2009
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Clive Hayden, The great thing about language is that we can make anything have a counterpart, just put the prefix "non" in front of it. There is no utility in trying to compare the natural and the non natural. Simply chalk the concept of the later up to the generous 'nature' of language and the creative abilities of the human mind.lastyear
December 16, 2009
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By "guidance", you mean a miracle, right? No one can ever prove or disprove the existence of miracles. Anyone is free to maintain that absent a sufficiently detailed explanation for the emergence of the first living organisms, (or any natural event) they'll continue to believe that it was a miracle. That is the very essence of a god-of-the-gaps position. The weakness of that position is that no matter where you make a stand you'll eventually have to move.lastyear
December 16, 2009
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lryna, So, I asked if science had proven the assumption and you said “no”. You then went on to deny that such an assumption is real within the sciences. Your denial falls with the sound of a thud against what is verifiably true. As if the constant pronouncement coming from science to the public is not real, does not exist, cannot be demonstrated, is a thing of fiction. How disingenuous can you be? Let’s look: “science cannot rule out that evolution (or anything else for that matter) is somehow guided.” Firstly, this thread isn’t about evolution and I am not certain if the word had even come up until you yourself brought it up. We were talking about a demonstration surrounding theories regarding the beginning of life on this planet. Why the change of topic? In any case, your comment is completely false. Science makes judgments about guided things all the time. (Forensics, SETI, historical sciences, etc). The reason that the methodologies of these disciplines are withheld from the biological sciences is for nothing but the protection of the core assumption, which of course, you deny exists. Even more interesting is how a question about science providing some empirical basis for its metaphysical assumption of unguided-ness morphed into a safehouse statement about an inability to disprove guided-ness regarding an issue not even under discussion. It’s awash in political maneuver. Just butt the tactical answer given to the simply question asked, and take it for a drive:
Do you think that science has provided the evidence that life came about by purely unguided processes? Science cannot rule out that evolution is guided.
(smirk) “It is therefore also incorrect to say that science “assumes” unguidedness. Really? Lets both start typing. You type all the quotes from science that proves your point and I’ll do the same for those that prove my point. Let’s see who dies typing. “Guidance is so ill-defined that it cannot be incorporated in scientific models in a useful way.” We’ve now moved away from the fact that science has failed to provide empirical evidence for an entrenched assumption, and we’ve all but forgotten that the assumption is peddled to the public every single day. We are now squinting our eyes and moving into the illogical justifications for ignoring the previous facts. The website you are on is dedicated to the proposition that we can make rational inferences to design from the observable evidence (in DNA, for instance) using the same explanatory techniques used within the other historical sciences, as well as forensics, and even the search for extraterrestrial life. “That’s not the same as denying that guidance exists.” Sure, whatever. But hey, thanks for confirming the evidence for the materialist’ assumption has not been provided. ;)Upright BiPed
December 16, 2009
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Upright BiPed: Sorry for the delay. I didn't ignore your question -- I was just too busy furthering our knowledge of the natural world.
Given the testability issues either way, this is where priori assumptions come into the picture. Science has operated with the assumption that purely unguided processes led to life for well over 100 years. It is the central theme in every textbook and is spoken to the public (to which science has a responsibility) on a daily basis, ranging from unabashed proclamations made on television and in newspapers, to popular books written by scientists using their status as a means to further the assumption. Do you think that science has provided the evidence that life came about by purely unguided processes?
No. Let me clarify a bit: science cannot rule out that evolution (or anything else for that matter) is somehow guided. Unless you would care to be more specific about how the guidance takes place, with sufficient detail to allow some testable predictions to be made. It is therefore also incorrect to say that science "assumes" unguidedness. "Guidance" is so ill-defined that it cannot be incorporated in scientific models in a useful way. That's not the same as denying that guidance exists.IrynaB
December 16, 2009
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Mr BiPed, Yes, if we can get past the synthesis of the physical components, things will be prepared to challenge the next level - whether or not autocatalytic sets actually form as predicted by mathematical models.Nakashima
December 16, 2009
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vjt, "How many more steps do they need to complete before they’ve built the simplest kind of cell in existence (M. genitalium)? 999,992." Whatever the numbers, this seemingly misses the point. Life is not the collection of its parts (ask a physiologists) as you acknowledge. Life is the intricate coordination of those parts into a function. Let's assume the synthesis of every part of an organism (after all, they do exist already). Take the M. genitalium you mention - what is its proteome count up to now - over a couple thousand for the smallest bacterium? (http://www.strgen.org/proteome/). A complete demonstration of the assumption that unguided processes lead to living organisms is not just getting to the synthesis of the nucleic acids, its the getting to those nucleic acids embedded with the instructions for the development of a proteome and metabolome and coordinating those into function and replication with the capacity of inheritance (without unwarranted investigator input). The work that has been done is incredibly interesting and will pay fantastic dividends (and is a heck of a testament to intelligent beings doing what intelligent beings do), but it does not demonstrate what is essential to life. It’s not even close. I think this is why many ID proponents are perhaps happy that all this research is being done. The sooner we get past the parts and the entrenched ideology; we can get down to the idea that it doesn't just coordinate itself. This is most likely to become apparent when we try to do it ourselves.Upright BiPed
December 16, 2009
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Mr Nakashima,
I think Mr Wisker is making a different point, that the kind of steps you are comparing are not in fact comensurable.
Yes, that was what I was trying to address, but now I don't think that was what vjtorley was trying to argue. At least, I hope not.Dave Wisker
December 16, 2009
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vjtorley, Before I reply further (which may take some time as I have other pressing things to get done this afternoon), I would like to point out that I was reacting specifically to your mentioning of the molecular weight differential between one nucleotide and the entire genome of M. genitalium. Somehow it seemed to me you were tying the number of chemical steps with the number of nucleotides, which didn't make sense. My apologies for misconstruing your argument-- I'm glad the error was on my part. As for the number of actual chemical steps and pathways, it is important to keep in mind the kinds of initial assumptions being made. Early on in our discussion here I mentioned that Sutherland's work was important because it threw out some initial assumptions that rendered the synthesis of ribonucleotides nearly impossible to achieve under pre-biological conditions. I think, as the work proceeds on abiogenesis, that other assumptions will be thrown out as well. I will mention a few in a subsequent comment.Dave Wisker
December 16, 2009
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Mr Vjtorley, I think Mr Wisker is making a different point, that the kind of steps you are comparing are not in fact comensurable. Counting the reaction steps, and assuming you get to append the result to a growing chain would be 4*600,000 reactions + 600,000 appends = 3,000,000 "steps". My estimate (which Mr Wisker is free to criticise or reject) of 1-10 million steps does bracket that number, but that process is hardly the one I had in mind. My estimate was devloped from the idea that the genome as a single molecule would grow through fusion events of smaller RNAs together. Fusion provides the selectable benefit of a better guarantee of having all of the instructions and components needed when you need them. I assumed random short mers of RNA were the "simple organic chemicals" available as starting points. Mers of 10-20 nucleotides in length could form abiotically and without selection on surfaces, and then become available to participate in organic chemistry leading to a first cell. Since I was starting with larger units (much larger than the inputs to the reaction pathways of Sutherland et al) I could have been extreme in my dependence on your wording and stated that between 100-500,000 events was sufficient, but I'd rather leave a few orders of magnitude wiggle room in in a SWAG like this. Actually, it is possible that a protocell could become self reproducing long before all of these RNAgenes linked up into one molecule. Then your question about number of steps to the longest molecule would be even shorter. But i think that would not be reflective of the actual size of the issue.Nakashima
December 16, 2009
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Dave Wisker (#108, #109) You made a substantive point in your recent post. I'd like to respond at length. First, here's the relevant extract from my post (#105):
Just to set the achievements of Sutherland et al. in perspective: The longest of the various chemical pathways leading to ribo-cytidine phosphate, the molecule they synthesized, has only four steps, as readers can verify from this link to an article in The New York Times (May 13, 2009) by Nicholas Wade, entitled "Reconstructing the Master Molecules of Life." The synthetic M. genitalium I mentioned above has a molecular weight of 360,110 kilodaltons (kDa), or 360,110,000 daltons. Printed in 10 point font, the letters of the M. genitalium JCVI-1.0 genome span 147 pages. By contrast, the RNA nucleotide which Sutherland et al. manufactured (ribo-cytidine phosphate) has a molecular weight of less than 360 daltons: less than a millionth that of the simplest bacterium.
You replied (#108, #109):
Methinks you are making an inappropriate comparison. The number of steps in the chemical pathway may only be four, but that doesn’t mean that pathway only resulted in one single molecule. It produced many ribo-cytidine phosphate molecules. That is, it produced one of the four basic types of ribonucleotides: those with the base cytosine (the letter "C" in the RNA sequence), and lots of them.. In other words, it generated lots of "C's".... Not only did the irradiation step generate cytosine and uracil, it also converted some of the ribocytidine (the "C" letter) to ribouridine, (the "U" letter).... Now, when you talk about the number of letters in an organism’s genome, you are actually counting the physical number of nucleotides, the building blocks of DNA . But you have to keep in mind in any genome there are only four different types of nucleotides in DNA and ribonucleotides in RNA, only four different "letters". In DNA, those letters are "A", "T", "C" and "G", and in RNA, "A", "U", "C" and "G"... So the pathway described by the authors is capable of producing one-half of the types of ribonucleotides needed to synthesize RNA. (Emphasis mine - VJT.)
First of all, I'd like to begin by citing an earlier part of my post, which you omitted in your response:
Mr. Nakashima (#98) estimates that between 1 and 10 million sequential steps would have been required to get from simple organic chemicals to the simplest bacterium, M. genitalium, the synthetic version of which has 582,970 base pairs, according to this press release by the J. Craig Venter Institute.
This is a vitally important point. In an earlier post (#65) to Mr. Nakashima, I asked him for an estimate of how many steps were required to get from the simplest organic compounds to the first cell, by the most direct pathway, ignoring side-reactants and focusing on the largest chemical molecule at each stage along the way, as it gets bigger and bigger. Mr. Nakashima was gracious enough to reply: he estimated between 1 and 10 million steps. That number provides me with a progress metric for origin-of-life research. In my post #105, I generously adopted the lower figure of 1,000,000 steps. Sutherland et al. managed to synthesize ribo-cytidine phosphate, via a four-step chemical process. You have kindly informed me that they also generated ribouridine, so let's make that eight steps for argument's sake. That's eight steps along a 1,000,000-step journey - which, as I wrote above, is about the distance from New York to Atlanta. That's very modest progress, to put it mildly. You think this is an unfair analogy. You seem to be arguing that half of the RNA molecule is made of these two ribonucleotides, so basically we're half-way to building one. I know you don't actually say that; but that's the rhetorical implication of your words, which a non-specialist reading your post might draw. In essence, you're saying: Sutherland et al. have already generated half the basic ingredients; once we've got the other half, all we have to do is put them all together. But that's precisely the problem: putting them all together. As you know perfectly well, RNA is not a repetitive polymer, like polythene. You don't get the same pattern repeating itself again and again and again. The sequencing is highly specific. And that's what scientists have to figure out. That's where the really hard work begins. Allow me to cite the Wikipedia article on RNA:
RNA is transcribed with only four bases (adenine, cytosine, guanine and uracil), but there are numerous modified bases and sugars in mature RNAs. Pseudouridine (Psi), in which the linkage between uracil and ribose is changed from a C–N bond to a C–C bond, and ribothymidine (T), are found in various places (most notably in the T-Psi-C loop of tRNA). Another notable modified base is hypoxanthine, a deaminated adenine base whose nucleoside is called inosine (I). Inosine plays a key role in the wobble hypothesis of the genetic code. There are nearly 100 other naturally occurring modified nucleosides, of which pseudouridine and nucleosides with 2'-O-methylribose are the most common. The specific roles of many of these modifications in RNA are not fully understood. However, it is notable that in ribosomal RNA, many of the post-transcriptional modifications occur in highly functional regions, such as the peptidyl transferase center and the subunit interface, implying that they are important for normal function. The functional form of single stranded RNA molecules, just like proteins, frequently requires a specific tertiary structure. The scaffold for this structure is provided by secondary structural elements which are hydrogen bonds within the molecule. This leads to several recognizable "domains" of secondary structure like hairpin loops, bulges and internal loops. Since RNA is charged, metal ions such as Mg2+ are needed to stabilise many secondary structures. Like DNA, most biologically active RNAs, including mRNA, tRNA, rRNA, snRNAs and other non-coding RNAs, contain self-complementary sequences that allow parts of the RNA to fold and pair with itself to form double helices. Structural analysis of these RNAs have revealed that they are highly structured. Unlike DNA, their structures do not consist of long double helices but rather collections of short helices packed together into structures akin to proteins. (Emphases mine - VJT.)
See what I mean? Allow me to conclude with a little anecdote, and I hope it conveys my incredulity when I hear people say we've made substantial progress towards solving the origin-of-life problem. A few months ago, my wife and I went shopping at the local mall. Actually, we were looking for a suitable birthday present for a nephew of ours, but our four-year-old son (who was with us) indicated that he wanted a little present too, so we thought, "Why not?" He pointed to a plastic model kit, containing 170 pieces, of six different kinds. The plastic kit was a model of a shark - just the thing a four-year-old boy would like. I should add that each kind of piece had its own specific shape. These pieces weren't Duplo blocks; they were designed to fit together in a particular way, although of course you could make all sorts of things with them, if you wanted. In other words, the geometry of the little pieces constrained the ways in which they could join together, but did not in any way dictate the 3D form of the creature that they were used to make. It's already starting to sound like DNA and RNA, isn't it - except that there are six letters, not four! When I got home, the first thing I did was sort all the pieces into their different kinds. I put them in six little plastic bags, and I thought to myself: "Piece of cake. All I have to do was follow the instructions." Boy was I wrong! Even with instructions, putting the shark together was not easy. At certain key points (especially the vertices), the diagrams were not detailed enough for me to figure out exactly which piece was meant to fit which. On top of that, it was not easy to make the different sides of the model shark join up properly: I had to virtually wrestle them into shape. Now, before I go on, let me ask you a question: what would be a good progress metric here? Would it make sense to say: well, he's got all the pieces, so basically his job's done? Of course not. You'd naturally say: how far along is he? How many pieces of the shark has he put together so far? That would be a good progress metric. Well, I never did finish that shark. I managed to put about 30 pieces together, so that my son could see the shark's face and a bit of its side. That's a miserable 30 pieces out of 170 - less than 20% completed. That's how we can gauge success or failure. I guess the manufacturers of the shark kit didn't realize that they'd have to make their instructions clearer for a dumb Dad like me. Fortunately, my son (who has about 300 toys - I've lost count) was not at all upset by my failure. Playing with the pieces was still an enjoyable experience for him. And fortunately, too, I can at least draw a realistic picture of a shark, even if I can't put a model of one together. The moral of the story is: pieces don't make a structure. Life is defined by its structure, and it's not a repetitive structure, but a highly specific one, which has to support all sorts of complex metabolic functions. Oh - and it has to be able to make a copy of itself. And it has to be capable of evolving - or else it would be unable to cope with environmental change. Quite a tall order - and far harder than making a model shark. Let's go back to Sutherland et al. They've done some excellent work. But what have they made? Two ribonucleotides. How many steps did that take, altogether, if we follow the longest path for each ribonucleotide they made? Eight or thereabouts. How many more steps do they need to complete before they've built the simplest kind of cell in existence (M. genitalium)? 999,992. Now do you see why I am underwhelmed? Eight steps along the road to Atlanta. You've got a long, long way to go.vjtorley
December 16, 2009
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lryna, Above you asked me a yes or no question. I gave you the answer (yes) but simply questioned the value of the question to begin with. I then asked you a yes/no question which you chose to ignore. I asked:
Given the testability issues either way, this is where priori assumptions come into the picture. Science has operated with the assumption that purely unguided processes led to life for well over 100 years. It is the central theme in every textbook and is spoken to the public (to which science has a responsibility) on a daily basis, ranging from unabashed proclamations made on television and in newspapers, to popular books written by scientists using their status as a means to further the assumption. Do you think that science has provided the evidence that life came about by purely unguided processes? “Yes or no?”
I was wondering, in fairness, what your answer is. You can certainly answer it - then choose to question its value in return. :)Upright BiPed
December 16, 2009
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Vjtorley,
Sutherland et al. are to be commended for including UV light and phosphates, and for simulating light and day. However, the wording in chemstandup’s post suggests that several parameters in their experiment (pH, temperature, reaction medium, reaction mixture, contact time, and energy input) were tightly controlled.
That is because they are trying to fully understand the chemistry involved (per a personal note from John Sutherland). This is important as the next step will be to determine the pathway(s) to purine ribonucleotide synthesis, which will probably be a more difficult nut to crack.
That suggests to me that the results they achieved would have been highly improbable on the early Earth.
I agree, but what they achieved has enabled origin of life workers to overcome what was seen as a very difficult problem-- getting pyrimidine ribonucleotides at all. Their out-of-the box thinking produced a fairly simple pathway to pyrmidines under conditions that better approached the early Earth than before. If they can find a way to produce purine ribonucleotides and understand that chemistry thoroughly, then the next logical step is to try and simulate the early Earth conditions even more exactly and let the system run by itself without such strict controls. That seems to me to be a coherent, logical, and methodical research plan.Dave Wisker
December 16, 2009
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But anyways, even given all the parts there still isn't any evidence those parts can configure themselves in such a way as to give rise to a living organism. If blind and undirected processes could give rise to semi-conductors does that mean blind and undirected processes can give rise to a PC?Joseph
December 16, 2009
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Dave Wisker, I know you were correcting Mung. My point was that his "answer" was contained in RNA and DNA.Joseph
December 16, 2009
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IryanB, If scientists did manage to create "life in a test tube" so to speak we would need to find out what level of intervention was required. Then we start backing off that intervention one step at a time.Joseph
December 16, 2009
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Mark Frank:
If life was designed then you have to wonder why the designer waited so long to implement this important stage.
Oramus beat me too it, but that explanation works.
But then we again run up against the problem that it is impossible to critique a design hypothesis without saying something about the designer’s motives and powers.
One doesn't have to know the motivations to critique the design.Joseph
December 16, 2009
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Mark, Actually, I think it would not be hard to fathom. First bacteria and plants as the means, (ramping up and completing the atmospheric cycle), then animals as the end goal. Note neither bacteria nor plants are dependent upon animals for survival but the converse is not true. Hence, the Cambrian explosion. Makes perfect design sense.
"If life was designed then you have to wonder why the designer waited so long to implement this important stage. But then we again run up against the problem that it is impossible to critique a design hypothesis without saying something about the designer’s motives and powers. Maybe it wanted to delay for reasons unfathomable."
Oramus
December 16, 2009
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