I find this very interesting, partly because I recreated Stanley Miller’s famous experiment for my high school science fair. It brings back fond memories of basement science projects. – Anthony
Primordial soup gets spicier
‘Lost’ samples from famous origin of life researcher could send the search for Earth’s first life in a new direction
Stanley Miller gained fame with his 1953 experiment showing the synthesis of organic compounds thought to be important in setting the origin of life in motion. Five years later, he produced samples from a similar experiment, shelved them and, as far as friends and colleagues know, never returned to them in his lifetime.
More 50 years later, Jeffrey Bada, Miller’s former student and a current Scripps Institution of Oceanography, UC San Diego professor of marine chemistry, discovered the samples in Miller’s laboratory material and made a discovery that represents a potential breakthrough in the search for the processes that created Earth’s first life forms.
Former Scripps undergraduate student Eric Parker, Bada and colleagues report on their reanalysis of the samples in the March 21 issue of Proceedings of the National Academy of Sciences. Miller’s 1958 experiment in which the gas hydrogen sulfide was added to a mix of gases believed to be present in the atmosphere of early Earth resulted in the synthesis of sulfur amino acids as well as other amino acids. The analysis by Bada’s lab using techniques not available to Miller suggests that a diversity of organic compounds existed on early planet Earth to an extent scientists had not previously realized.
“Much to our surprise the yield of amino acids is a lot richer than any experiment (Miller) had ever conducted,” said Bada.
The new findings support the case that volcanoes — a major source of atmospheric hydrogen sulfide today — accompanied by lightning converted simple gases into a wide array of amino acids, which are were in turn available for assembly into early proteins.
Bada also found that the amino acids produced in Miller’s experiment with hydrogen sulfide are similar to those found in meteorites. This supports a widely-held hypothesis that processes such as the ones in the laboratory experiments provide a model of how organic material needed for the origin of life are likely widespread in the universe and thus may provide the extraterrestrial seeds of life elsewhere.
Successful creation of the sulfur-rich amino acids would take place in the labs of several researchers, including Miller himself, but not until the 1970s.
“Unbeknownst to him, he’d already done it in 1958,” said Bada.
Miller’s initial experiments in the 1950s with colleague Harold Urey used a mixture of gases such as methane, ammonia, water vapor and hydrogen and electrically charged them as lightning would. The experiment, which took place in a closed chamber meant to simulate conditions on early Earth, generated several simple amino acids and other organic compounds in what became known as “primordial soup.”
With the gases and electrical energy they produce, many geoscientists believe the volcanoes on a young planet covered much more extensively by water than today’s served as oases of raw materials that allowed prebiotic matter to accumulate in sufficient quantities to assemble into more complex material and eventually into primitive life itself. Bada had already begun reanalyzing Miller’s preserved samples and drawing conclusions about the role of volcanoes in sparking early life when he came across the previously unknown samples. In a 2008 analysis of samples left from Miller’s more famous experiment, Bada’s team had been able to detect many more amino acids than his former mentor had thanks to modern techniques unavailable to Miller.
Miller, who became a chemistry professor at UCSD in 1960, conducted the experiments while a faculty member at Columbia University. He had collected and catalogued samples from the hydrogen sulfide mix but never analyzed them. He only casually mentioned their existence late in his life and the importance of the samples was only realized shortly before his death in 2007, Bada said. It turned out, however, that his 1958 mix more closely resembled what geoscientists now consider early Earth conditions than did the gases in his more famous previous experiment.
“This really not only enhances our 2008 study but goes further to show the diversity of compounds that can be produced with a certain gas mixture,” Bada said.
The Bada lab is gearing up to repeat Miller’s classic experiments later this year. With modern equipment including a miniaturized microwave spark apparatus, experiments that took the elder researcher weeks to carry out could be completed in a day, Bada said.
Parker, now a student at Georgia Tech, led the study. Co-authors include H. James Cleaves from the Carnegie Institution of Washington in Washington D.C.; Jason P. Dworkin, Daniel P. Glavin and Michael P. Callahan of NASA Goddard Space Flight Center in Greenbelt, Md.; Andrew D. Aubrey of the Jet Propulsion Laboratory in La Cañada Flintridge, Calif. and Antonio Lazcano of the National Autonomous University of Mexico in Mexico City.
Scripps Institution of Oceanography: scripps.ucsd.edu
Scripps News: scrippsnews.ucsd.edu
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Comment pwl March 22, 2011 at 11:34 pm Version 2.0: Woops, please let me fix the grammar of second sentence that got mangled in the editing evolution, which also shows the need not just for self assembling systems that can reproduce but that which can also correct errors during copying and transcription. [:)]
No Eric, it’s the same “complexity”, watch Wolfram’s video in full and read his tome, ANKS, and you might have your eyes opened to a whole new aspect of Nature. It’s likely you just think it’s a different “complexity” because if you were to think that it’s the same complexity it would mean that we’re just an electro-bio-chemical-information-processing machines made of bio-goop and that we’re not magically special in some way; but it’s the same complexity that Wolfram talks about, and we are just made of bio-goop. We’re just bio-goop-mostly-ugly-bags-of-water that can reproduce and that are made up of many complex systems built upon simple systems generating complex behaviors. RNA and DNA – low level key parts of our systems – are in many ways cellular automata that can copy themselves or be copied, and which self correct most although not all errors during copying. Wolfram’s discoveries are relevant to the processes of life at the atomic, molecular, cellular and even quantum levels.
Self assembly is a step required before self-copying aka self-reproduction. It’s a matter of “exploring the space of simple molecules that self assemble” to find the ones that can “self-copy” and thus replicate which is a prerequisite for life. Nature can easily conduct exhaustive combinatorial searches through such even vast combinatorial spaces. All it takes is at least one time having something that self assembled and can replicate to get the entire process going, however it’s very possible that it occurred many times. That takes time and the Earth (and possibly the Sol System) had plenty of time to shake and bake the first life.
“Can you please point me to a single example of a self-reproducing molecular system that is known to have arisen through natural causes?”
Look in the mirror Eric and you’ll see such a system that must have gone through that step and with N (where N is a very large number) of generations of copying resulted in you.
Self assembly is not only very interesting but essential to the process, as is the self assembly of self reproducing systems, even if they are haphazard for many generations at first.
When you dig into Wolfram’s ANKS – as well as other required fields relating to the origins of life – you may find yourself altering your limited perceptions and conceptions.
Origin of life – lemma: life is possible – as we exist – end lemma.
Add Hugh Everett’s interpretation of Schrodinger – since all possible combinations of quantum events exist, life must exist in a (unknown percentage) subset of these combinations, and must continue in a (unknown percentage) subset.
Unfortunately, since we cannot traverse the combinations, we must be content to continue to exist in this sheath of exploding subsets of possibilities. G-d throws dice, and they each come up all six ways (or up to twenty, depending on the dice). And G-d keeps adding to the number of dice thrown at each turn, as this universe keeps expanding. Even so, we may run into the Bekenstein bounds, in a trillion or so years. Until then, I expect people to keep looking for answers.
Just one old guy’s opinion!
Life! One of mankind’s holiest grails is to define “life”, to explain it’s existence, to try and explain the ‘creation” story, the way in which “life” came into existence and became what we call ‘life” and then the rise of ‘intelligence”, nature’s greatest gift to life on this planet, a gift that enables mankind alone out of all the life forms on this planet, to sit here and ponder this question of the hows and whys of the very beginnings of “life” and “intelligence” itself.
Nobody will ever know just how “life” came into existence.
Nobody will ever know how many possibly uncountable times “life” started and was then snuffed out.
Nobody will ever be able to recreate those same conditions for “life” itself has now irrevocably altered those conditions and filled those then vacant niches with it’s now long dominant life forms.
I am a bit amused at the absolute certitude expressed by some highly qualified commenters above about the impossibility of some types of chemical reactions and conditions contributing to the initial molecular organising that was perhaps needed to create a type of self replicating molecule, a self replicating molecule that was the precursor for life itself.
Such self replicating molecular mats could have spread over vast areas and there would have invariably been mistakes in the assembly of those interacting molecules as they came in contact with other elemental molecules or lighting strikes into the vast mass, hot volcanic acidic drops of molten magma with it’s mix of excited radical atoms, molecules and chemicals, intense ultraviolet light and even intense nuclear radiation from natural reactors in some regions or oil films and clay sheets that the newly created molecules could assemble on.
Uncountable failures occurred but just very rarely perhaps only once every few tens of thousand years in that seething elemental mass of assembled molecules, an assembly mistake stuck and a new self replicating and more complex molecular structure was created and began propagating.
None of this can ever happen again on this planet as all those niches and reaction sites are filled and loaded by far more advanced organisms and the far more advanced molecular structures of today nor will we ever know how many times life got started and was then destroyed until finally against all the odds that the Cosmos could throw against it, “life” finally made it into a molecular structure where it could start to strategically adapt to changes and “life” as we know it was finally on it’s way.
Life I believe is extremely common across the Universe for the conditions that allowed “life” to be created on this planet, that’s if it was actually created on this planet and not elsewhere in the Cosmos , are as far as we can guess also common right across the Universe
But “intelligence” that is another question altogether.
Life could have settled down to an almost status quo and it did so if we are to believe the archeobiologists for the aeons of the early Earth as life in it’s most simple forms filled all the available niches that it could exist in.
But that Earth was a far from a stable environment for those extremely primitive life forms that existed just above a self replicating molecular level so the mistakes in assembly went on and only a tiny proportion of those new off spring of those molecular mistakes could adapt and survive the changing Earth as it rolled on through it’s long creative phase.
The Earth continued to change and the “life” forms had to adapt and this forced changes until a point was reached where life began to develop the ability to consciously react to changes in conditions it existed in and then and only then was there any sort of assurance that ‘life” on this planet was going to survive.
“Intelligence” was a whole new ball game and it came very late in the Planet’s history. Probably over 85% of the Earth’s life time of 4.5 billion years had passed and some 3.2 billion years had passed since “life” first appeared on the planet before what we would call recognisable “intelligence” first appeared probably no earlier and perhaps a good deal less than some 600 million years ago.
“Intelligence” simply would not exist on this planet except for the radical changes in climate, the weather systems, the heat , the cold, the ever changing oceans and land masses all of which forced “life” to adapt and often adapt fast.
You need a constantly changing, rapidly evolving, chaotic mixed up planet to force the changes and to eliminate the life forms that cannot adapt fast enough or adapt at all.
Then long intervals of stasis are needed for the newly rising life forms and their newly developing intelligence to settle down and fill the niches before another episode of violent change again forces the evolving life forms to again adapt or get wiped out.
It is the extremes of this planet but extremes that were quite limited in their range, a very unusual combination, that has forced the development of “Intelligence” as we know it.
The slow adapters were eliminated and wiped out and more often than not this no doubt removed a life form that was developing or could have developed a level of intelligence.
But that’s life!
And we as a race need to heed the circumstances.
There were so many twists and turns and nasty probabilities working against the rise of intelligence that it’s existence in my opinion is far more of a miracle than the creation of life itself.
And “Life” in my opinion is probably quite common across the Universe.
“Intelligent life”, even at the probably modest level we humans operate at, may be very, very rare indeed.
Why did the original experiment include hydrogen? It is too light to have remained in the atmosphere indeed soon after formation there was has been described as the magma ocean. The surface was molten, at about 1200C so hydrogen in this excited state would definitely have deserted the sinking ship that was to become earth. The primordial atmosphere more probably contain methane, hydrogen sulphide, ammonia, and our old friend CO2.
I’m surprised that they didn’t find life in those sample vials, what with all those amino acids sitting around together for some 50 odd years!
And I should have mentioned Water vapour.
Fascinating, Anthony… many, many thanks for shining your light on this.
Good argument for archiving your data, if nothing else!
Best,
Frank
This is mythology, not science.
Black smokers at spreading ridges appears to be on the focus for the origin of life. The energy flow and chemistry is more favorable than an over all sea of soup.
1) It appears that the chance for life to appear on this (or any other) planet is so statistically impossible that it cannot happen in the lifetime of this universe, or any other, and…
2) It happened anyway.
Thus #1 is an incorrect assumption. Chance was only part of it. Chemical evolution, chemical selection and high energy input did it. Life happened because the energy and chemistry forced it. Given the same conditions throughout the universe, and there is a lot of life out there.
Anthony,
I follow the time line to the past through the study of wet ice ages and our oldest salt mines. Water evaporation is a key to understanding the creation of an atmosphere that has water vapor in it.
This shows that salt was far more concentrated and water was almost as pure as today and not a bunch of chemical compounds. Meteors and comets, many have a great deal of water compounds longer than this planet was created.
Planetary rotation was faster in the past, which needed more density not to fly off.
Anthony,
Ever hear science say that the salt on this planet came from the rocks?
They have it backwards. The salt, silt and fossils created the rock.
On facebook I posted…
It may seem strange to some but only negatives can prove a positive… Until a better negative comes along!
I was actually referring to the four basic tenets of logic, AND/NAND OR/NOR. They can only be reduced to the negatives with NAND being the most reduced form.
Is this a basic that’s been forgotten?
DaveE.
Instead of rehashing old debates about the roles of god/chance/whatnot in the origin of life, does anyone want to take a stab at suggesting a reason why it should matter one way or the other? Would you change anything about your behaviour or lifestyle if you knew for sure which it was?
Tornado in the junkyard comes to mind.
Primordial hogwash, I think. Chemical feedstocks are entirely too dilute and energy input too weak to support vigorous autocatalytic activity in bodies of water. Far more plausible processes can be found in Tom Gold’s Deep Hot Biosphere and in ocean floor geothermal vents.
One of the puzzling things in life is life! What is extremely improbable over a few million years may be probable (a thousand times more likely) over a few billion years. This misunderstanding (or underappreciation of the immense scope of time) is one of the major blinders of the “can’t happen” crowd.
jrwakefield: “Chance was only part of it. Chemical evolution, chemical selection and high energy input did it. Life happened because the energy and chemistry forced it. Given the same conditions throughout the universe, and there is a lot of life out there.”
So your idea is that life is inevitable because the laws of chemistry and physics cause life to form? I’m curious, what’s your theory? How does this occur, are you aware of some as-yet-undisclosed law of chemistry and physics that would cause this to happen. Please enlighten us.
Who knew “you are what you eat” applied to molecules. If it doesn’t violate the 2nd law of thermodynamics who am I to disagree?
The Miller-Urey experiments are very important historically, but IMO are not too relevant to how life evolved. They were the first of a number of experiments that demonstrated that complex organic compounds can be created from simple precursors, without the help of living creatures/plants. Neither is the exact mix of stuff Miller used all that important. The early earth — like the earth today — probably had a primary surface chemistry system as well as a number of niche situations with quite different physical characteristics. We don’t actually KNOW what any of them looked like and probably won’t for many decades, or centuries, or maybe ever. It’s probably plausible to assume that any molecule necessary to a particular evolutionary scheme could have existed — at least in small quantities.
And yes there are two things that we do not understand very well:
1.0 Exactly how one particular family of atomic organizations came to consistently dominate its mirror image form. Once life evolved, that ceases to be an issue since living creatures have the preference built in. But how did that come about?
2.0 Last time I looked, there’s a pretty big gap between simple organic compounds with a few or maybe a few dozen atoms in the largest molecules, and the simplest self replicating systems which are (or were when I last looked) proteins with over 1500 atoms. (and also, are in no way, shape, or form, alive).
pwl, thanks, I’m familiar with Wolfram. I’m also familiar with Kauffman and the emergence theorists. Neither of these are very helpful in understanding the formation of life.
“We’re just bio-goop-mostly-ugly-bags-of-water that can reproduce and that are made up of many complex systems built upon simple systems generating complex behaviors.”
This kind of statement illustrates my prior point exactly: many people take a very simplistic view of life and don’t take time to think through what is actually required for life. As a result, they tend to vastly underestimate the task at hand.
“Self assembly is a step required before self-copying aka self-reproduction. It’s a matter of “exploring the space of simple molecules that self assemble” to find the ones that can “self-copy” and thus replicate which is a prerequisite for life.”
Can you point me to a single example of a self-replicating molecule? (Hint: we’re not talking about a self-replicating system, we’re talking about a self-replicating molecule, which is what you posit was somehow formed to allow life to get off the ground.)
“Nature can easily conduct exhaustive combinatorial searches through such even vast combinatorial spaces.”
This is just evidence that you haven’t run the math. The combinatorial space required to get even a simple complex of the required proteins is way beyond the available time and resources of the known universe. This is precisely why other folks are trying to come up with some other self-organizing mechanism, just like jrwakefield alluded to in the comments above.
I asked, “Can you please point me to a single example of a self-reproducing molecular system that is known to have arisen through natural causes?” And you responded “Look in the mirror Eric.”
Very funny, but, sorry, that is an invalid response. First of all, you don’t have any evidence that life arose through natural causes, you are just assuming and stating it as though it were a fact. Second, we’re talking about the formation of life; that is the entire question at hand. You can’t provide a valid explanation for life by circularly referring to life. I didn’t think it was necessary in the context of the discussion to say so, but just so we are clear, allow me to rephrase the question:
In the context of a discussion about the formation of life, can you please point me to a single example of a self-reproducing molecular system that is known to have arisen through natural causes (without invoking circular references to life, the very thing we are trying to explain)?
Thanks for this one, Anthony. I brilliant example of why I am a daily visitor here.
I remember seeing a working model train set in store window during WWII, when I was somewhere past three years old. I get a similar feeling of wonder and fascination from posts such as this.
The current understanding of the evolution of Earth’s atmosphere has the “primordial” atmosphere much like that of Venus; 90 times our current atmosphere’s mass and over 98% CO2. But Earth has been in the Habitable Zone from the beginning, liquid water has been present in vast amounts for a very long time. Much of the primordial CO2 has been sequestered into carbonate rock.
Miller’s experiments used a composition of gasses that did not match Earth’s atmosphere during the period when life first appeared, so they are not really all that illuminating.
There’s been lots of evolutionary biology study on Phenotype, Evo/Devo. Multi-cellular, etc. but it’s rather bizarre that no one has done any on the cell itself. It got over looked. So, if you go trawling through the popular books about evolution such as Dawkins and the like you won’t find any evolutionary cellular biology. Because no one has done any. Came as a shock to me but then I never could understand why I couldn’t find any. It’s the last frontier if Dr. Michael Lynch of Ind. Uni. is to be believed. I recommend put this link in your search box and go through the presentation given my Lynch. You’ll be up to speed very quickly…at least to Jan 2010. But then, if you don’t want to see your favourite arm waving book author disssed, …. Dawkins, Behe, Gould…. then I wouldn’t. It lasts an hour and is a presentation given by him summarizing a much longer presentation. Infact, the whole KITP conference is available….free. 24/7. As to whether there is or isn’t meta-physics involved: perhaps we can wait until the cellular science is done before rulling meta in or out, afterall, that’s where it all begins.
Hour version – Quicktime
http://online.itp.ucsb.edu/online/bblunch/lynch/rm/qttv.html
Longer version – Quicktime
http://online.itp.ucsb.edu/online/evocell10/lynch4/rm/flashtv.html
As for this experiment by Miller. It’s very telling that it could be done in by kid in his basement but no one has bothered to reproduce it (and get the results he overlooked).
Very telling. Obviously; they feel it’s not science noteworthy so why the excitement now?