This article by Michael Marshall on the The Secret of How Life on Earth Began is probably the best summary on the topic I have read to date. I compiled a quick glossary below.
It’s not just about the “smoker” vs “souper” debate (sometimes referred to as the Metabolism First vs RNA World Brouhaha). This article also examines other disparate competing hypotheses regarding the origin of life and even suggests that a unifying grand hypothesis may be possible.
A great read!
oparin haldane charles darwin atp tree of life chemiosmosis rna world franklin hershey chase peter mitchell cyanide nick lane alkaline vents hydrothermal vents clay meteorites geothermal pond volcanic pond ultraviolet compartmentalisation first lipid world genetics first montmorillonite citrate magnesium copper lipid precursors hodge podge world metal ion core deborah kelley lost city william martin luca last universal common ancestor origin of life reactor pier luigi luisi glycol nucleic acid günter wächtershäuser jack corliss michael russell pyrite david bartel philipp holliger gerald joyce peter nielsen polyamide nucleic acid pna albert eschenmoser threose nucleic acid tna eric meggers miller urey watson crick orgel john sutherland thomas cech walter gilbert thomas steitz jack szostak ribozyme rna enzymes ring of life vitalism trofim lysenko alexander oparin j. b. s. haldane armen mulkidjanian jillian f. banfield friedrich wöhler benjamin moore biotic energy warm little pond
I am disappointed that the article neglected to mention some of Stanley Miller’s best ideas – i.e. life may have began on ice; a narrative picked up by Hauke Trinks.
Thanks. That is, indeed, a pretty good summary.
I lean toward a “metabolism first” approach. But I’m open to the other possibilities. Perhaps we might never be able to sort it out for sure.
Random bits of stuff colliding with other random bits of stuff until the moment of the miracle of life (it just happened, that’s all) is as inconceivable today as it ever was.
Nonsense. It’s conceivable to anyone with an open mind. Even more conceivable to anyone who’s had a course in organic chemistry.
It’s been said before, but one has to have a science education before one can critique science intelligently.
Organic Chemistry. Got it.
Random bits of inorganic stuff colliding with other random bits of inorganic stuff until the moment of the miracle of life (it just happened, that’s all) is as inconceivable today as it ever was.
It was never inconceivable to me.
I grew up as a theist. I saw God as doing wondrous things. But he pretty much always did it by natural means. So maybe he created a wondrous nature, but thereafter it is all nature.
I dropped out of theism. There may or may not be a God who may or may not have done wondrous things. But since the wondrous things were done through nature, it suffices for me to concern myself with nature.
But if God was doing it, it wasn’t done by “natural means,” it was done by supernatural means.
So you reasoned that if God can do it supernaturally, through natural means, then who needs God, because by natural means done by a supernatural God really means done by means without any God.
I think we don’t know enough yet to say whether the chemical interactions that give rise to life were truly “random” (whatever that means) or governed by laws we haven’t yet discovered.
I doubt the reason most people need God is because He directly created a flagellum.
I agree, which is why no one really believes that caricature.
Anyway, I agree that really is a very well written and balanced article.
As usual, you know for sure what did not happen but fail to mention what did. How does the origin of life work in Mung world?
Or governed by laws we have discovered. Life gives birth to life.
And we have examples of mineral substance being generated by living beings as we see when we look at the white cliffs along the South East coast of England.
Rumraket,
Evolutionists just hate it when people sum up their theory as bluntly and honestly as possible.
They need all the fluff and diluting obfuscation to make it sound more palatable.
Its like when people call out Trump as a misogynist. Then he always complains, I never said that, I never said I was a misogynist, I respect woman more than anyone, I just think they are sexual objects that are inferior to men, and that they are for man’s pleasure and disposal. I am not the caricature you fabricated!
I bet Donald trump believes in evolution. He probably also doesn’t understand what it means, the same as you guys. “Its just the nature of nature….”
Until you go far enough back and life couldn’t have existed, so it had to emerge somehow thus violating the rule. There’s just no way around this.
Besides, that’s not a law at all. There’s no difference between atoms that make up living organisms, and atoms that make up rocks, dust and gases. In fact living organisms convert “inanimate” matter into their own constituent materials through chemical and physical processes (which themselves aren’t “alive”). The distinction between life and non-life is synthetic and arbitrary. In a way, Photolithotrophs and Chemolithotrophs are violating the “law” when they convert “dead” materials into “living” ones.
I worry that there’s a problematic assumption here. The argument seems to be something like this.
1. There are no constituents of living things that are not present in non-living things.
2. An ontologically real difference is a difference in composition or constituents.
3. If a conceptual distinction is not tracking an ontologically real difference, then the distinction is wholly conventional and arbitrary;
4. Therefore, the distinction between living things and non-living things is wholly conventional and arbitrary.
I definitely think that (2) is false, and I think that (3) might be false as well. And I think you need both of them to get (4) from (1).
The problem with (2) is that it disallows us from considering organization as being just as real as components. But differences in organization are differences in causal powers — the causal powers of a trout are very different before and after being put in a blender. So if you want your ontology to track causal efficacy — which is I think a plausible criterion, and also the criterion we naturalists appeal to when we disallow gods and spirits in our ontology — then organization has got to have some ontological status.
In short, the difference in organization between living and non-living things is a real difference, neither arbitrary nor conventional. The fact that vitalism is false doesn’t require us to dispense with the living/non-living distinction, but rather requires us to re-think it.
I also have some worries about (3), because I think that a conceptual distinction can reliably track real patterns even if those concepts are not the best characterization of those patterns.
Trump being Trump says he believes in both creationism and evolution.
Thanks very much for that article Tom! Great read.
I had always assumed that the people looking for the start of life in one place were wrong. That what must have happened is that there were hundreds or thousands of different environments each producing unique products. These products would diffuse to other environments to be modified and so and and so on. After many such iterations somehow life formed.
But its seems that there is evidence that life formed in a specific type of location without much input from others. If this is true is has very profound implications: Life should exist in many places in the galaxy, perhaps on millions of worlds. Up till now I had the bad feeling that earth might be the only planet with life in the galaxy and perhaps even the universe.
Kantian Naturalist has hit the nail on the head! Bravo!
I would lick to pick up his football and run with it:
During my salad days as an undergraduate, I toyed with the idea of majoring in philosophy. I was particularly enamored of the writings of Gilbert Ryle, P. F. Strawson, and Ludwig Wittgenstein. All three could be considered “Ordinary Language Philosophers”.
Here is a fast and easy reference to what I am on about:
http://plato.stanford.edu/entries/analysis/s6.html
I particularly appreciate KN’s oblique aside wrt :
…“random” (whatever that means)” not to mention “…or governed by laws we haven’t yet discovered.”
In deference especially to P F Strawson (former mentor to my own esteemed former professor Jonathan F Bennett) I suggest that NK is on to something here.
Take just one example: http://theskepticalzone.com/wp/in-slight-defense-of-granville-sewell-a-lehninger-larry-moran-l-boltzmann/
I part paths with NT on one minor quibble. Clearly, laws already discovered are not only necessary but also sufficient to explain the abiotic synthesis of complex polymers leading inexorably and perhaps even inevitably to the Origin of Life.
The problem is that many present have great difficulty (myself definitely included) to manage any correct understanding of many terms already existing (such as “randomness”) much less correct interpretations of natural laws already discovered (such as the Second Law of Thermodynamics).
I never thought I would ever admit this in public, but Sal’s inchoate cut and paste plagiarisms in his most recent “In Slight Defense…” thread has cleared up some fuzzy thinking on my part (special thanks to walto & Joe F). ITMT – I must confess, I remain in debt to Sal.
I also note that Sal’s thread has managed to generate an all too prolonged and still continuing series of repetitive responses exemplifying the “philosophy of ordinary language” problem I am alluding to. (Special thanks to one persistent individual on Sal’s thread who clearly suffers a decided reading comprehension problem, moreso than even Sal)
You say that life couldn’t have existed back then. Why not?
I believe that much of life as it is in the present day could not have existed in the beginning because the environment has changed and lifeforms are adapted to their environments and should not be seen as separate from their environments. Just as I believe that quetzalcoatlus would be unable to fly in today’s environment and a typical brachiosaurus would be crushed under its own weight nowadays. Environments are not static and life is not static.
Why could there not have existed forms of life suitable to the conditions at the time before first life was thought to have originated?
I agree. The way I think of it is this. If we had a large number of planets that were an exact duplicate of earth- that reproduced all of the environments almost exactly- what are the chances that life would form? I think it entirely possible that life would form every time. There are systems where complexity emerges automatically and the emergence of life from non-life could be one of those examples.
On the other hand life might emerge very rarely, because some exceedingly unlikely event is required- an asteroid impact a precise distance from a volcanic pool – a very rare molecule somehow protected from instant hydrolysis.
Short of creating full blown life in an early earth simulator, I dont think we can ever know which is the case.
Do you have any empirical evidence of examples of life not coming from life?
Atoms may be the same whether they are a constituent of living or non living matter. By the same token as there is no difference between the letters you and I are using would you say that there is no fundamental difference between the writings of either of us?
I would say that in order to grasp the fundamental differences we need to look at a higher level than the alphabet.
Kantian Naturalist,
I would go along with your concerns. I do not believe that a reductionist view gets us closer to reality.
No one knows. Not me, not you, not anyone. We can’t even define what life IS yet.
But we know it when we see it.
There is absolutely no reason why Quetzalcoatlus would not be able to fly in today’s atmosphere or why Brachiosaurus would be unable to support it’s own weight.
The ability of an organism to fly or stand is based on the laws of physics. Unless the laws of physics have changed since the Jurassic period, or the mass of the planet or atmospheric density have changed much since then, then a Brachiosaurus could certainly support its weight as well now as it could when it lived, and likewise for a Quetzalcoatlus to fly.
It’s certainly true that the ecological niches that those animals once occupied no longer exist, and in that respect they couldn’t live — but please don’t confuse what is true as a matter of ecology with what is true as a matter of physics!
Right, just like most of the evolutionists on this thread.
They believe in unguided Darwinian evolution, because it was designed that way, and because nature obviously has the intent and laws to create complex life.
And that would be an arbitrary distinction, since dead material also has organization, it’s just a different organization.
Basically what makes life alive is the ability of cellular entities to grow by taking in fuel or constituents from the surroundings, copy their information and then divide. You can exclude the cellular-requirement or metabolism, if you want to call viruses and self-replicating molecules life, but then you’ve basically taken a step closer to showing that there isn’t much difference between life and non-life. All the individual aspects of life are found, by themselves, outside of it. Metabolism is itself composed of a subset of basic reactions, which is the building up of constituents at the expense of energy and the breaking down of constituents to release energy. Both of these are found outside life. Then we know of cellular compartments (lipid or fatty acid vesicles) that grow and divide yet we don’t call them life. We know of information transfer and copying from crystal growth, or heck, the fact that some RNA molecules can copy themselves.
The collection of these two or three basic physical processes is what we recognize as life. You might call the whole phenomenon of them being together in the the same small area “organization”, but then you’ve just sort of lumped the whole thing together without looking deeper, apparently on purpose so as to argue life is different.
OMagain,
What makes you think anyone is alive Omagain? According to Rumraket the definition of living is arbitrary.
It is sort of inconvenient that we have something called organic chemistry in that case though, but a lot is inconvenient if we start listening to skeptics talk about the world.
Yeah, it’s called the origin of life. If it came from life, it wouldn’t be the ORIGIN of life. That there was an ORIGIN of life is an empirical fact, provided you are familiar with the timeline of the universe.
Are you saying there IS NO origin of life?
If so, would you mind telling me how life existed when the universe was a 100 trillion degree C, hot quark-gluon plasma? Or before molybdenum was formed in subsequent generations of supernovae explosions?
I disagree with both You & NK as explained already
I don’t (yet) see any need to invoke unknown laws.
Just unknown events. And perhaps, unknown transient conditions.
I have to admit I’m not quite sure what you disagree with in my post. It seems to me that the 2 possible outcomes I gave for my hypothetical situation get at what we mean by ‘random’ in the present topic.
Consider a flat plane with objects rolling around randomly in a confined space. Billiard balls wont work. Make them long rectangles or 3-flat pointed stars…something like that. As they bounce around nothing will much happen and the whole thing might be described by the Ideal Gas law. Now consider attaching magnets to each in a particular pattern. Its inevitable that they’ll now clump together in branching patterns that might be predicted mathematically. Its 100% certain that this will happen. But if one asks for a very specific pattern, particularly one that might be at odds with the pattern of magnets, the likelihood that this will form in a given period of time drops. The thing that I’m asking is this: is life like the first example. A pattern that will arise almost inevitably as long as conditions are favorable? ( and how specific is ‘favorable’?) .or is life like the second example; a very specific and unlikely pattern.
My thoughts exactly.
Not a disagreement really but as I suggested earlier more of a “quibble”
Cf Petruska’s observation & my tentative suggestion above why some of us may be speaking at cross purposes
And not a specific organization.
Is it really an arbitrary distinction to note that one paramecium is alive and another dead? I don’t think so.
To be sure, there may be very different organizations that could be considered to be life, but one thing they’re going exhibit is the effects of evolution and to be flexible enough in their information systems to be able to evolve. Maybe some day we’ll have designed life and may see things differently, but at this time I don’t think that we have reason to consider life as being anything but something that can and did evolve. It is a significant distinction from actual designed objects.
Why would that mean there isn’t much difference between life and non-life? I don’t think that anyone really supposes that there’s a sharp distinction between life and non-life early in OOL processes, but there’s a pretty big difference between the life we see today and primordial soup, hydrothermal chemistry, etc.
And yet, what’s arbitrary in noting that a paramecium is living, while a disintegrated paramecium is not and can never again be living (practically, rather than in any theoretic possibility whatsoever)?
No, it’s more like looking deeper while not forgetting that there’s a huge difference between a self-maintaining and potentially reproducing organism made up of constituents, and those constituents separate from those organisms that by themselves could not maintain their existence or potentially reproduce.
Glen Davidson
Ah yes, Well there certainly were transient conditions. There were radical changes in atmospheric and ocean chemistry in just the transition from the Ediacaran to the Cambrian so I’m sure there was a much more radical shifts on the early earth. The question is did the emergence of life absolutely require these shifts over the course of say… 100 million years, or did life get jump started in some specific environment over a much shorter period of time. In this case life could have adjusted to whatever changing conditions occurred. I think this is relevant for predicting how rare or common life is in the universe
Neil Rickert,
I’ve never seen a ‘metabolism first’ proposal that really made much sense, except by stretching the term ‘metabolism’ beyond usefulness, as a mere synonym for ‘carbon chemistry’. I don’t doubt that many reactions involved in metabolism happened in the prebiotic earth. That merely indicates a thermodynamic direction. But when one proposes some kind of continuity between a primitive ‘metabolic’ system and a subsequent invention of replication, I don’t see how that is supposed to work. Without a co-ordinated system that can benefit from its own tuning, such reactions will simply fall into a thermodynamic well, or at least will lack any impetus to move in the direction of Life.
On the other hand, it’s much easier to see how clumsy dsRNA replication might exploit the thermodynamic paths available for the benefit of the replicating system, and rapidly get better through natural selection. It’s no accident that ATP is an RNA monomer. Energy and replication first.
phoodoo,
You’re right, of course. The only way to make life is to have a bloke with a big white beard say ‘kaboom’ and make all these zebras and stuff just appear out of nowhere. Is that a fair summary of your position?
Okay, then we disagree. You seem to have this sort if idea that just because the distinction is arbitrary, there is no difference. Of course there is, but to call one thing alive and another dead is arbitrary labeling. I’m sorry, it just is.
Things we know that evolve, evolve because they can copy themselves with small changes(mutations) in them. Living cells aren’t the only things that can do this. We wouldn’t call those other things alive, because they aren’t cells and don’t have metabolism(because we have decided to add those to the definition of life). But each of those two things are also found outside of life.
Again, life is “just” a particular collection of basic physical and chemical processes in the same entity. It is arbitrary to call that collection of physical and chemical processes “alive” and another that lacks one or more of them, “dead”.
Who says there isn’t “much difference”?
Again, the fact that we have arbitrarily set the line somewhere, doesn’t mean there isn’t a difference. I’m not saying there isn’t a difference between life and non-life, merely that it is arbitrary and to think the difference is somehow fundamental, as if to imply dead material could never become alive or give rise to it, is a mistake.
Take an analogy. Call anyone below 180 cm short, and anyone above it tall. Arbitrary right? Yes, entirely. Does that mean there is no difference between short and tall people? No. One really IS taller than the other. Does that mean short people can’t grow and become tall? No. Does it mean short people can’t give rise to tall people? No.
And things that are alive, really are alive, rather than dead. But the act of deciding what to call alive, as opposed to dead, is what is arbitrary. You, we, us, people before us, have arbitrarily set the line somewhere and decided to call some things alive, and other things dead.
“pretty big” seems rather relative and arbitrary to me.
At what point does it become a “disintegrated” paramecium, exactly? When does it stop being living and start being dead, and why there?
Right, and when the collection of them are organized in the right way, in the right environment, they can “maintain their existence and potentially reproduce”. Cool them down slowly and gradually, at some point one or more of the processes either stops entirely or becomes so slow as to be immeasurable. Heat it up again and the processes slowly speed up again, when does it start being alive? When the first cell-division takes place? But then it would be dead, despite being actively growing and metabolizing until the very moment it starts splitting in two. Why’s it alive then, and not 42 microseconds before that? Because you arbitrarily decided so.
Sorry, the distinction between life and non-life, while referring to something real and measurable, is still arbitrary. Arbitrary does not mean imaginary, or neglible, or even insigificant or without consequence.
Actually, the beard came later. First it was “Let there be Light.” Then the beard grew in while he waited for man to evolve.
That’s damned close to what “arbitrary” means, all right:
Just the first result I found from a Google search
I’d like to know what isn’t an arbitrary label, then.
Actually, it’s mostly just life that does this, other than in little areas or experiments set up by humans. But I won’t say it’s all that evolves “naturally,” it’s just the one rather complex phenomenon that evolves sans brains or guidance. Yet of course to bring up evolution isn’t to deny other aspects of life, as I didn’t deny the other aspects.
About as arbitrary as saying that an automobile runs fine, or that it doesn’t run at all.
Well, you. It wasn’t me. I was responding to this:
Plus, if there is much difference between life and non-life and you make your distinction based on authentic properties of life vs. non-life/dead things, then it’s hardly an arbitrary distinction.
Here’s a serious mistake you’re making with language–the line drawn between life and death is arbitrary with respect to a certain ambiguous range, while this does not mean or imply that normally the difference between a living organism and a non-living entity is actually arbitrary, even if, once again, there may be a small range in which the line has to be drawn arbitrarily. It’s like the colors, red and yellow are not arbitrary distinctions, while there is a range within which the line drawn between them is arbitrary with respect to that range. Outside of that ambiguous range it becomes non-ambiguous, much as a person who has been “dead” for three hours is non-arbitrarily different from the living person, in spite of the fact that there is an ambiguous time in which any line drawn between life and death is arbitrary with respect to that range of time.
Of course I’ve never said or implied that the difference between life and non-life is “fundamental.”
No, that’s where you’re not getting the point. Taller and shorter are not arbitrary, and presumably one chose 180cm as a cutoff point because most people think that one taller than, say, 170-190 cm. is “tall.” The exact point “180 cm.” is arbitrary with respect to a certain range, but not altogether arbitrary, for it’s within the range above which people are considered to be “tall” (or perhaps above a certain percentile for height).
Don’t mistake the arbitrariness of a certain point within a transitional zone to mean that it is arbitrary to consider the properties to be distinct in the ranges outside of that transitional zone.
We set a line that is arbitrary with respect to the transitional zone because there is an enormous difference between “fully alive” and “fully dead.” The latter distinction is quite non-arbitrary, while the placement of the “point of death” within the “zone of dying” is at least somewhat arbitrary.
Well it’s not, it’s a stand-in for some issues that are fairly well understood but that lies out of the scope of a fairly short comment. I could have used jargon instead, but so long as I wasn’t getting into the specifics it hardly would make a real difference.
What difference does that make, other than that you seem not to realize how unambiguous the distinction actually is because you seem to think that any arbitrariness in picking a point within the transitional zone makes the entire distinction arbitrary? It doesn’t.
It doesn’t even make sense to me that something that had been in “suspended animation” is dead at that time and becomes alive later. In some organisms life can “stop” or become “suspended,” but they’re generally not considered to be “dead” at that time. Only if their ability to “reanimate” is destroyed are they considered “dead.” Grayish area, no doubt, but it’s not altogether unlike shutting down a machine and restarting it, despite some rather marked differences in detail.
If real and measurable, and your distinction follows the “real” aspect, it is then not arbitrary. The word “arbitrary” doesn’t apply to real and measurable differences as understood and stated by humans.
Actually, for the most part it really does, although it may just be random rather than imaginary or some such thing.
Glen Davidson
Could God design a world where “random bits of stuff” could collide with other “random bits of stuff” and produce something extremely basic that produces copies of itself?
What about a world where bits of stuff are chemically attracted to each other?
As it isn’t really on topic I’m happy to say that we have differing beliefs on the matter and leave it at that.
Hi Allan
I don’t think you may be misunderstanding Martin & Russell (or perhaps I am misunderstanding you).
All autotrophs fix carbon dioxide in redox reactions using hydrogen (from H2O or other electron donors like H2S), by five (or is it 6?) processes generically labeled aerobic and anaerobic respiration. These pathways ALL exploit chemiosmosis and proton gradients across membranes! The various versions of “fermentation” were evolutionary after-thoughts; a prime example of co-evolution in eubacteria & archaeabacteria.
Martin & Russell invoke the abiotic chemistry of alkaline vents as a less than just tentative explanation of this chemiosmotic commonality that must have existed in LUCA before LUCA gave rise to the two different versions of plasma membranes now witnessed in Eubacteria & Arcaeabacteria. I find their arguments compelling.
Pushing this line of reasoning further: Martin & Russell maintain that compartmentalization was necessary before the catalytic functions of RNA could come to bear AND the best candidate for such compartmentalization were micro-pores in ancient alkaline vents.
Yes, we are all in agreement that many reactions involved in metabolism happened in the prebiotic earth leading to the emergence of life. However, a careful reading of this article indicates we are NOT all in agreement exactly where those aforesaid reactions were occurring; i.e. where did life emerge… in those alkaline vents or somewhere else? Or (as the article also tentatively suggests) did those cyclic and self sustaining abiotic chemical reactions (in a reducing atmosphere) perhaps originate in those vents but were co-opted elsewhere? That last suggestion is very very iffy IMHO. I agree with Martin & Russell that we must never take our eye off chemiosmosis and proton gradients as being the sine qua non of life.
Here is a brief synopsis by Martin & Russell who themselves accord RNA no less importance than you do… if I am understanding one and all correctly
best regards
The beginnings of physical life on earth is not an empirical fact, it is a matter of speculation.
There is evidence that life took on a form which became solid enough to leave traces in the earth, so there was a point where living forms originated with earthly material bodies.
Well its obvious that living forms with earthly material bodies and DNA could not exist in these conditions. But does life have to be restricted to this? You believe that the way we define life is arbitrary. So what is life?
A report in Science says:
Stars have identities, lives, deaths and generations. Why would you not class this as life? Surely you would be making an arbitrary distinction to say that life must contain some sort of nucleic acid.
It would take me too long to track the paper down but I recall that at the alkaline vents there is simple molecule with a high energy phosphate produced that could have been the precursor to ATP
Hi REW
Nick Lane and others suggest the molecule you are describing was probably Acetyl Phosphate.
Here is a great paper:
http://www.nick-lane.net/Sousa%20et%20al%20Phil%20Trans.pdf
relevant quote:
best regards
Thanks for the ref! I have to say I’m surprised that so many think chemiosmosis played a prominent role in early or quasi-life. I would have thought the whole process is far too complicated. It is possible that energy could be extracted directly from the electron flow and the proton gradient was a useless byproduct that was only exploited later on? Could energy be extracted from the proton gradient with non-protein molecules?
I had always assumed that substrate level phosphorylation, perhaps catalyzed by RNA or RNA-peptides came before the ETC.
Might it be useful to consider what early life or quasi-life might have actually needed the energy for? Its probably a much simpler list than today. There was probably no need for ion pumps, movement etc. Maybe the only need was to produce high energy monomers or some other reactive molecule that could drive other reactions. It seems to me that the more narrow and modest the energy requirement the more likely quasi-life could have evolved a way to harvest it.
Here is another great reference that addresses your questions:
http://www.nick-lane.net/LAM%20BioEssays.pdf
Two relevant quotes. First:
They make a great case that Fermentation and Substrate Level Phosphoryloation represents an evolutionary after-thought not present in LUCA.
The second seminal quote:
This article is also definitely worthy of perusal.
ooops the second seminal quote referred to above was actually