Abiogenesis / Origin of Life

[Milla]

The RNA world

I have noticed throughout most of Dawkins works there is very little reference to the origin of life. Since Dawkins is preoccupied with evolution it’s hardly surprising, but I think one of the main problems most people have with evolution is believing (or at least understanding) how life could come about from ‘nothing’. There was a large part of The Blind Watchmaker dedicated to some bizarre theory that life was once inorganic and there was a tiny part of the God Delusion dedicated to the fact that life only had to ‘start’ once; that is once a self-replicating molecule came into existence evolution was almost inevitable. Since the basic building blocks of everything from viruses to human are identical it’s clear that it did only start once but what happened next?

Self replicating molecules on their own aren’t enough to explain how life as we know it today came into being. I think there should be some time dedicated to the ‘RNA world hypothesis’, if not in one of Dawkins books (assuming that another comes out) then maybe in a popular science book dedicated to the subject of the origin of life.

I personally believe in the RNA world hypothesis, that early in life RNA (or some crude derivative of it) functioned as a self-replicating molecule and a catalyst, due to the fact that the only biological catalyst that is in use RNA today is – the machine that synthesizes proteins! Nice chicken and egg avoider there. Excluding for divergent evolution in some viruses, all functional molecules present in living things today that are not cofactors are proteins. The only exception to this are the tRNAs and the ribosome that act to assemble proteins. Proteins do play secondary roles such as ribosome scaffolding, adding amino acids and as a release factor but the main part are still made of RNA.

I think its clear that once the simple version of the protein synthesizing system came about ribozymes were slowly but surly replaced by enzymes with one exception: the machine that created them. Obviously evolution wouldn't allow such a huge leap as that! How come Creationists have never been asked why the Intelligent Designer designed the protein synthesizing system this way? That would be a damned hard question to answer! He was drunk and forgot he was working with protein perhaps?

The reason I mention this is because it seems most intelligent people (like my mum for instance, whom I was speaking with earlier today on this issue) understand evolution but refuse to believe that life could have come into being in the first place without being put here. If more people are to understand and believe in evolution they must first understand how life began. The RNA world may not have been the simplest form of life on Earth but it certainly explains how life can start without any help and I think a good deal of modern popular science should deal with this subject if evolution is to prevail over this supernatural nonsense.

[RichardPrins]

The Ancestor's Tale touches on "The RNA World" near the end of the book...


(oh, and Welcome!) :D

[mbjturner]

**
Hi milla;

This is my first post to this forum, and I decided that since yours was the most recent, least developed thread, it's the most reasonable place to dip my toe in these unfamiliar waters.

Moreover, you ask a fundamental ontological question--"What is the ultimate origin of all existence, including the existence of Life?"

Many human beings, [at least those given to philosophical reflection], ask themselves that question at some point in their lives, and many determine their own behaviours in accord with whatever answer they come to accept as most acceptable. Acceptable in terms of what they would like to believe, or, would like others to believe, or both. Sadly, most human beings hate philosophical reflection on difficult ontological questions such as the question of 'origins', and simply swallow whatever POV is politically correct among those they hang with. But I hope that this board is for thinkers, and not just regurgitators.

As for Dawkins and 'Origins', he and his Materialist camp decided to arbitrarily cut off research into 'Origins' at the fact of Material existence; that is, the fact that the material, physical universe exists. If you you ask them, "Why does the universe, or anything, including Life, exist?", their answer is simply, "It just does, that's all!" For them,the universe, existence, simply, " is", and it is what it is, and it is the way it is, for no known or knowable reason. "It 'just happened', that's all." IOW, a non-answer to a fundamental question is proffered as if it meant something. What is in fact no more than an evasion, is trumpeted as 'scientific truth'.

A lot of us prefer rational answers, rather than arbitrary evasions, to deep, basic, fundamental issues. Issues, such as "Origins", whose answers impact our social behaviours in every way imaginable. Some others are terrified of what may lurk beyond, "This universe [and any others imaginable] just popped into existence, without reason or cause, out of nothingness and nowhereness, all by itself, for no reason at all." So they, like Dawkins and other atheists who conflate atheism with science, simply say, '' We'll just stick to what we can measure and observe, because an answer to 'origins', i.e., to where it all came from, and WHY it is the way it is, might impact our social behaviours in ways that we might find disagreeable. Such as socially formalised and established religions are wont to do.

[Milla]

This is not a matter of philosophy or the origin of the universe; that is a matter for physicists to deal with. I’m saying that there should be more in popular science books about origins, because evolution alone is not enough to explain why we are here. The RNA world and its remnants (like the ribosome) is a good place to start.

[DGMontgomery]

As for Dawkins and 'Origins', he and his Materialist camp decided to arbitrarily cut off research into 'Origins' at the fact of Material existence; that is, the fact that the material, physical universe exists. If you you ask them, "Why does the universe, or anything, including Life, exist?", their answer is simply, "It just does, that's all!" For them,the universe, existence, simply, " is", and it is what it is, and it is the way it is, for no known or knowable reason. "It 'just happened', that's all." IOW, a non-answer to a fundamental question is proffered as if it meant something. What is in fact no more than an evasion, is trumpeted as 'scientific truth'.

That is not true, actually. Science more says "We don't know, but we are trying to find out. Here is what we know so far".

When religion says "God made it", what they are really saying is "We don't know, and we were not meant to know (or are unable to ever know)".

Quite a large amount of reasearch has been done on the origin of life and matter and energy, from natural causes, and it is generally overlooked by those who claim science avoids these types of questions.

[MZbiologist]

The RNA world

I have noticed throughout most of Dawkins works there is very little reference to the origin of life. Since Dawkins is preoccupied with evolution it’s hardly surprising, but I think one of the main problems most people have with evolution is believing (or at least understanding) how life could come about from ‘nothing’. There was a large part of The Blind Watchmaker dedicated to some bizarre theory that life was once inorganic and there was a tiny part of the God Delusion dedicated to the fact that life only had to ‘start’ once; that is once a self-replicating molecule came into existence evolution was almost inevitable. Since the basic building blocks of everything from viruses to human are identical it’s clear that it did only start once but what happened next?

Self replicating molecules on their own aren’t enough to explain how life as we know it today came into being. I think there should be some time dedicated to the ‘RNA world hypothesis’, if not in one of Dawkins books (assuming that another comes out) then maybe in a popular science book dedicated to the subject of the origin of life.

I personally believe in the RNA world hypothesis, that early in life RNA (or some crude derivative of it) functioned as a self-replicating molecule and a catalyst, due to the fact that the only biological catalyst that is in use RNA today is – the machine that synthesizes proteins! Nice chicken and egg avoider there. Excluding for divergent evolution in some viruses, all functional molecules present in living things today that are not cofactors are proteins. The only exception to this are the tRNAs and the ribosome that act to assemble proteins. Proteins do play secondary roles such as ribosome scaffolding, adding amino acids and as a release factor but the main part are still made of RNA.

I think its clear that once the simple version of the protein synthesizing system came about ribozymes were slowly but surly replaced by enzymes with one exception: the machine that created them. Obviously evolution wouldn't allow such a huge leap as that! How come Creationists have never been asked why the Intelligent Designer designed the protein synthesizing system this way? That would be a damned hard question to answer! He was drunk and forgot he was working with protein perhaps?

The reason I mention this is because it seems most intelligent people (like my mum for instance, whom I was speaking with earlier today on this issue) understand evolution but refuse to believe that life could have come into being in the first place without being put here. If more people are to understand and believe in evolution they must first understand how life began. The RNA world may not have been the simplest form of life on Earth but it certainly explains how life can start without any help and I think a good deal of modern popular science should deal with this subject if evolution is to prevail over this supernatural nonsense.

miRNAs, are micro RNAs, that perform regulatory functions. So far, about 300 conserved miRNAs have been identified. This field has emerged only in the last 5 years. One of the main reasons for findind these miRNAs, came from studies of RNA interference, and the celluar machinery it uses, which is highly conserved across a wide range of species, both simple and complex.

The reason they had been missed for a long time, is due in large part to technological limitations, and that people did not know to look for them, let alone how. We now know better. RNA has a much more diverse role in biological functions than what has been historically recognized. Your arguments above are based on a very limited and inaccurate picture of biological processes.

[mbjturner]

**

dgmontgomery quoted my statement, i.e., "As for Dawkins and 'Origins', he and his Materialist camp decided to arbitrarily cut off research into 'Origins' at the fact of Material existence; that is, the fact that the material, physical universe exists. If you you ask them, "Why does the universe, or anything, including Life, exist?", their answer is simply, "It just does, that's all!" For them,the universe, existence, simply, " is", and it is what it is, and it is the way it is, for no known or knowable reason. "It 'just happened', that's all." IOW, a non-answer to a fundamental question is proffered as if it meant something. What is in fact no more than an evasion, is trumpeted as 'scientific truth'. ", and then continued--

That is not true, actually. Science more says "We don't know, but we are trying to find out. Here is what we know so far".

To which I must reply that although that may be what 'science', [as the personification of astro-physicists et al] is saying, ' science' is not Richard Dawkins nor all the atheistic Materialist/Physicalist/Positivist/Mechanist/Naturalist, etc., etc. adherents of his ideology, and it was, [as anyone looking at my original statement can see], those ideologues, and not 'science' , to whom I referred. The fact that dgm immediately makes the mistake of conflating materialist [etc] ideology with 'science' is quite telling. The atheist spin that they are one and the same has been so successful that many people today make that error automatically. But, automatically accepted or not, it is still a fallacy.

DGM goes on to say,

When religion says "God made it", what they are really saying is "We don't know, and we were not meant to know (or are unable to ever know)".

I am unable to discern in any particular fashion just who it is that 'religion' personifies. I have little use for the social/cultural constructs [I believe that Dawkins created a neologism for social constructs, didn't he? Rhymed it with 'genes', by no materialist accident.] IAC, since I am not an adherent of any church, cult, or 'organised religion' of any sort, but speak strictly from the POV of an amateur philosopher on the ontological issue of 'origins', I care no more for what 'religion' may or may not say, since 'religions' speak only for themselves, just atheists speak only for themselves, and none of them speaks for science, philosophy, or myself.

Finally DGM says,

Quite a large amount of reasearch has been done on the origin of life and matter and energy, from natural causes, and it is generally overlooked by those who claim science avoids these types of questions.

I would like to know if all of this research has borne any meaningful fruit, especially WRT the origins of Life, [as Milla asked for in her OP]. So far as I know, Miller-Urey was a dead [forgive me] end in this regard, and no-one has moved a single step forward in the understanding of the origin of life itself in the past 40+ years.

However, whether 'science' has made any advances in this regard makes no difference wrt atheism and materialism, since 'science' only observes the mechanical details of whatever 'is'. It never confronts the ontological issue of the origins of these mechanical details, [that is, the 'why' and the 'how' of physical existence], wisely leaving this to philosophical cosmology. Atheism,[materialism's cosmology], like theism, is just another cosmological postulate-- philosophy, not science, a 'religion' like any other.
The sole difference between the theist postulate and the atheist postulate being that where theists postulate a 'god' of some kind as the ultimate origin of everything, atheists simply say that there is no 'ultimate origin', no 'uncaused cause', of everything. Their 'origins' postulate is that in some kind of self-generating "poof" existence, 'just happened, that's all'. Creatio ex nihilo!! This vacuous fallacy informs all of materialist biology, including their positions on the origin of life itself, and its subsequent evolution.

[Diplo]

I have noticed throughout most of Dawkins works there is very little reference to the origin of life.

The first chapter of his first book, 'The Selfish Gene', is mostly about this.

[Ein Sophistry]

The question of abiogenesis is still very much an open one and may even be insoluble. This is not, however, for the reasons creationists would like to believe. The problem is one of underdetermination—that is, we have a number of probable candidates and no definitive way to choose between; we can only shade the relative probabilities. The question is really one of which candidate came first, and although we can calculate which of the candidates are easier to randomly obtain than others, this still cannot conclusively settle the matter [to illustrate the point, suppose you simultaneously and successively roll a 6-sided die and a 100-sided die. Now, the 6-sided die is more likely to give you a 1 before the 100-sided die does so (P=0.1667 for each roll of the 6-sided die vs. 0.01 for each roll of the 100-sided die). Nevertheless, it is still perfectly possible to get a 1 on the first roll of the 100-sided die.]. I reiterate: the open question of abiogenesis is one of how it occurred, not whether it occurred. In the following paragraphs, I will demonstrate the probability of one of the more popular candidates for our ultimate biotic ancestor: a self-replicating RNA molecule.

A few years ago, I did a little calculating on the matter of abiogenesis similar to but a bit more detailed than Dawkins' treatment in TGD. I reproduce the essence of it here.

David Bartel of MIT’s Whitehead Institute for Biomedical Research has discovered a number of RNA configurations which can function as enzymes and so catalyze their own replication. Eklund and Bartel found that viable self-replicating “ribozymes” comprised 1 in every 10^20 possible RNA nucleotide chains (Nature 192). That, then, is our probability, and it is still an impressive figure. If we allow for the creation of one nucleotide chain per second, we would need a length of time greater than 253 times the present age of the universe in order to guarantee getting a self-replicator.

But, this calculation is merely sequential; it considers only one population of the required component molecules on one planet. Surely several such populations existed on Earth—probably on the order of billions. However, because molecules generally don’t fossilize, making it difficult to determine their past concentrations, I will stick with the extremely conservative figure of one completed RNA strand per planet per second. Throughout the following calculations, I have endeavored to err on the side of extreme caution wherever a fair degree of uncertainty was involved. Nevertheless, I think you’ll still find the results compelling.

We must now set a reasonable time frame. Life appears to have arisen on Earth no later than 1 billion years after its formation and this seems a fair window within which to allow for the formation of our crucial ribozyme (see Endnote 1 for more on this). Allowing one completed RNA strand per second, this gives roughly 3.15 * 10^16 seconds per suitable planet to work with.

So, how many suitable planets are there? Around each star is what’s called a “habitable zone,” an area at a distance from the star relative to its size and age containing a range of temperatures within which water can condense and life similar to that on Earth can form (Franck, et al 22-3). How many planets, then, can we expect to fall into these critical habitable zones? In a study for the Potsdam Institute for Climate Impact Research, Franck, et al arrived at a figure of around 4.8 * 10^7 habitable planets within the Milky Way galaxy (24). While this seems like a striking number, it was calculated quite conservatively. Franck, et al posited only one planetary system per 100 hundred stars and only 12 habitable planets per 1000 planets generally (see Endnote 2).

Now, what about the rest of the universe? It remains a mystery how many stars exist in total. However, a team of astronomers led by Dr. Simon Driver at the Australian National University estimated the number of stars presently within reach of our telescopes to be 7 * 10^22 (“Star survey”). When we divide the number of habitable planets within the Milky Way by the total number of stars in the Milky Way (Frank, et al used the figure 4 * 10^11), we get 0.00012 habitable planets per star. Multiplying this by the total number of observable stars in the universe gives us 8.4 * 10^18 habitable planets, and multiplying this figure by the number of RNA strands completed per planet within our billion year window gives us 2.646 * 10^35 RNA strands. This means that we would have gotten not just one of our one-in-10^20 strands needed for our ribozyme; we would have gotten—even with our conservative figures—around 2,646,000,000,000,000 of them! And that is only among the stars we can currently see! With the rise of this self-replicator, natural selection comes into play and the creative work becomes decidedly nonrandom, permitting all the great diversity and complexity of life we see today.

Endnote 1: I acknowledge that allowing 1 billion years for these chemical reactions may seem like an unwarranted assumption to a young Earth creationist. Note, though, that our final figure gives us 15 orders of magnitude to play with and 1 billion constitutes only 9. I used the figure of 1 billion years based on the oldest fossils, but we could easily reduce our window to 1,000 years or even 1 year and still get many thousands of the ribozymes we require.

Endnote 2: One may be thinking at this point that I’m abstracting too far from the physical evidence, that my estimates—conservative as they may seem—are simply too far removed from data we can actually see to be of much worth. I will try to assuage those concerns here. On the matter of the availability of the chemical constituents required for our ribozyme I submit Halley’s Comet, in which amino acids and nucleotides have been detected (via spectrophotometry), and the Murchison meteorite, which has yielded over 90 different extraplanetary amino acids. Clearly, these compounds don’t seem especially difficult to come by.

The matter of the number of planets in the universe requires more explanation. At present only extremely large (think Jupiter times ten) extrasolar planets can be detected directly by telescopes. However, there are a number of alternative ways smaller planets can be detected. A sufficiently large (at least Jupiter-sized) planet can exert gravitational effects on its parent star. These can be measured and even used to determine the planet’s size and distance from the star. I refer you to The Extrasolar Planets Encyclopedia, which keeps an updated list of all the stars investigated for the presence of planets, all the planets detected, the method(s) by which they were detected, their mass, distance, and certain other features. Note that of the apparently 229 stars investigated, 176 have, at the date of this writing, yielded at least one planet large enough to be detected; 21 of them have yielded more than one. This is far more optimistic than the 1 planetary system per 100 stars posited by Franck, et al—and this is not even including smaller, presently undetectable planets, moons, asteroids, comets, and other bodies on which, as we’ve seen, organic chemistry is certainly possible.


Ekland, E. H. and Bartel, D. P. “RNA-catalysed RNA polymerization using nucleoside triphosphates.” Nature. 383; 1996: 192.

Franck, S., et al. “Habitable zones and the number of habitable planets in the Milky Way.” BioSpace. 22-24. 24 Jun. 2004. http://biospace.nw.ru/astrobiology/Articles2002/Astrobio_franck_22_24.pdf.

“Star survey reaches 70 sextillion.” CNN.com. 23 Jul. 2003. http://www.cnn.com/2003/TECH/space/07/22/stars.survey/index.html.

[Eamonn Shute]

Life appears to have arisen on Earth no later than 1 billion years after its formation ..... Allowing one completed RNA strand per second, this gives roughly 3.15 * 10^15 seconds per suitable planet to work with.

One year is about 3 * 10^7 seconds, so 1 billion years is more like 3 * 10^16 seconds (just nit-picking!)

Your figure of one completed RNA strand per second is extremely cautious, as you say - to me it seems over-cautious! On a planet the size of Earth one would expect a huge amount of organic chemistry to take place all the time, so I would expect the actual figure to be many orders of magnitude greater than this, even if you err on the side of caution, although I have no idea what a more realistic figure would be. Any thoughts on this?