Scientist suggests life began in freshwater pond, not the ocean

Feb 14, 2012 by Bob Yirka report
water

(PhysOrg.com) -- For most everyone alive today, it's almost a fundamental fact. Life began in the ocean and evolved into all of the different organisms that exist today. The idea that this could be wrong causes great discomfort, like discovering as an adult that you were adopted as a child. Nonetheless, a team of diverse scientists led by Armen Mulkidjanian is suggesting that very thing; instead of life beginning in deep thermal vents in the ocean, the prevailing view, they say it perhaps instead started in landlocked freshwater pools created by thermal vapor. Their theory is based, as they explain in their paper published in the Proceedings of the National Academy of Sciences, mostly on the idea that the sea is just too salty to provide the ideal conditions necessary to spur life into existence.

Mulkidjanian and his colleagues argue that in looking at the way cells are made today, it’s hard to imagine they got their start in water that was far saltier than it is now. They point out that cells in all living have a much higher proportion of potassium to sodium, whereas the is the reverse. Such high levels of salt would have made it difficult for cells to synthesize proteins, they say, making it extremely difficult for them the form into the molecular machines with strong walls seen today. Such thick walls would not have existed when cells were just starting to form, making it almost impossible for them to get started, grow and mature.

In contrast, they say, the conditions found on land during the time period when life is believed to have started, was likely far more conducive. In addition to the existing pools of fresh water created by the condensation and cooling of geothermal vapor, there were the higher temperatures that are believed to have existed worldwide. In addition, they say that those pools of , or mud, likely had many of the same ingredients found in modern cells: phosphate ions, zinc, manganese and especially potassium. Thus the newly forming original cells would not have had to work hard to keep out harmful sodium ions. Also, to counter arguments that newly developing on land would be stopped in their tracks by harmful UV radiation from the sun, the team notes that both RNA and DNA have been shown to be stable under such exposure.

Despite the team’s compelling arguments, there are likely to be many doubters, and rather than converting most in the scientific community, this new idea is likely to spark debate that will almost certainly continue for many years to come.

Explore further: Climate researchers measure the concentration of greenhouse gases above the Atlantic

More information: Origin of first cells at terrestrial, anoxic geothermal fields, PNAS, Published online before print February 13, 2012, doi:10.1073/pnas.1117774109

Abstract
All cells contain much more potassium, phosphate, and transition metals than modern (or reconstructed primeval) oceans, lakes, or rivers. Cells maintain ion gradients by using sophisticated, energy-dependent membrane enzymes (membrane pumps) that are embedded in elaborate ion-tight membranes. The first cells could possess neither ion-tight membranes nor membrane pumps, so the concentrations of small inorganic molecules and ions within protocells and in their environment would equilibrate. Hence, the ion composition of modern cells might reflect the inorganic ion composition of the habitats of protocells. We attempted to reconstruct the “hatcheries” of the first cells by combining geochemical analysis with phylogenomic scrutiny of the inorganic ion requirements of universal components of modern cells. These ubiquitous, and by inference primordial, proteins and functional systems show affinity to and functional requirement for K+, Zn2+, Mn2+, and phosphate. Thus, protocells must have evolved in habitats with a high K+/Na+ ratio and relatively high concentrations of Zn, Mn, and phosphorous compounds. Geochemical reconstruction shows that the ionic composition conducive to the origin of cells could not have existed in marine settings but is compatible with emissions of vapor-dominated zones of inland geothermal systems. Under the anoxic, CO2-dominated primordial atmosphere, the chemistry of basins at geothermal fields would resemble the internal milieu of modern cells. The precellular stages of evolution might have transpired in shallow ponds of condensed and cooled geothermal vapor that were lined with porous silicate minerals mixed with metal sulfides and enriched in K+, Zn2+, and phosphorous compounds.

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antialias_physorg
3.8 / 5 (26) Feb 14, 2012
The Bible claims that plant life started on the continents before fish and other aquatic life was created.

So?
The Bible also claims that Earth was created before the sun, the Moon and the stars.

And since when did an unsubstantiated claim ever carry any weight?
bewertow
3.5 / 5 (13) Feb 14, 2012
Reported for religious trolling. Please take your fairy tales about magical zombies who claim to be their own father elsewhere.
Sean_W
4.5 / 5 (8) Feb 14, 2012
Most aquatic life lives by consuming suspended or dissolved nutrients from the water. This really makes it hard for life to have started in the oceans.


The first plants would have been single celled organisms and the first organisms would have been much simpler then plants--or even photosynthetic bacteria. They would have been little more than self-sustaining chemical reactions.
Sean_W
4 / 5 (4) Feb 14, 2012
There is still debate as to whether a simple set of chemical reactions formed a metabolism first or if an autocatalyzing RNA occurred first. So throw in this question and I suspect that the author is right when writing that there will be a lot of debate and further research. The problem these questions is that even if we think it did occur one way doesn't mean it could not have happened the other. That makes proving which way it went much harder.
nkalanaga
3.2 / 5 (6) Feb 14, 2012
Sean: Exactly. In an effectively infinite universe any possible event is likely to happen somewhere. Even if we could prove how life appeared here, it wouldn't have had to follow the same path on other worlds. The best we can do is show that a particular sequence of events is both physically possible and statistically likely. If so, it has probably occurred at least once.

If one considers a "god" to be any existing being with sufficiently advanced technology, even "divine creation" has probably happened. After all, we already talk about spreading Earth life to other planets.
antialias_physorg
3.9 / 5 (21) Feb 14, 2012
You mean an unsubstantiated and unproven idea like evolution? And no it has not been proven. All they have found is a bunch of bones that they manipulate to support the evolution theory.

You mean apart from all the DNA and RNA evidence? The speciation observed in the lab and in nature? That's a wee bit more than 'a bunch of bones'.

http://www.talkor...ion.html
(go to the list of references at the end of the article. That should give you a good starting point to catch up on the state of speciation and evolution)
Callippo
1 / 5 (6) Feb 14, 2012
The tiny freshwater ponds have one disadvantage, which is their stationary character. The evolution of liposome eobionts would proceed a much faster under repetitive shaking, which can be provided with tidal waves. http://aetherwave...ife.html The medium-sized ponds with sufficient coastal waves would be an ideal environment from this perspective.
kochevnik
4.1 / 5 (17) Feb 14, 2012
@mmud You mean an unsubstantiated and unproven idea like evolution?
Your entire post history, beginning in May when you joined, is anti-science, and your fallback is fairy tales. Be gone troll.
Telekinetic
3.8 / 5 (16) Feb 14, 2012
The Bible claims that plant life started on the continents before fish and other aquatic life was created.

So?
The Bible also claims that Earth was created before the sun, the Moon and the stars.

And since when did an unsubstantiated claim ever carry any weight?


You mean an unsubstantiated and unproven idea like evolution? And no it has not been proven. All they have found is a bunch of bones that they manipulate to support the evolution theory. Now I am not saying that the earth was created in a day, that makes no sense either. But science must be proven...prove to me that you can evolve a single cell organism into a land walking creature....

Evolution requires millions of years- you can't expect a person to jump out of a petri dish in a couple of weeks. Creationism precludes the millions of years of transformation by its stance of a 6,000 year old earth. You just walked into a biker bar wearing a sequined thong.
PS3
1 / 5 (14) Feb 14, 2012
Evolution doesn't take millions to start it off.It should be just a chemical mix,but they can't do it.

Can't be that hard to go through all the possible combinations..can it??????

PosterusNeticus
3.4 / 5 (17) Feb 14, 2012
The Bible claims


This is a science site. Moderators, surely we don't have to suffer through walls of religious spam here? And it is spam, being completely irrelevant to both the topic and to the nature of the site as a whole.
bewertow
3.2 / 5 (11) Feb 14, 2012
1 Mods take care of all this creationist spam ASAP!
Deesky
5 / 5 (5) Feb 14, 2012
For most everyone alive today, it's almost a fundamental fact. Life began in the ocean and evolved into all of the different organisms that exist today. The idea that this could be wrong causes great discomfort, like discovering as an adult that you were adopted as a child.

Does a scientific article really need such trite pap as an introduction? I'm sure those weren't Mulkidjanian's words.

All it does is serve to bolster the anti-science purveyor's views of rigidity and dogmatic thinking and how dare anyone ever challenge what a kid might have read in a book fifty years ago!

The scientific reality, of course, is very different, where all kinds of ideas are challenged all the time. This type editorialized reporting which manufactures controversy is a disservice to science.
nkalanaga
5 / 5 (2) Feb 14, 2012
Callippo: Another idea along your line - would the oceans have been that salty? The salts and minerals have largely come from erosion. If life began in the first quarter of Earth's existence, would there have been enough erosion to make a difference? If not, the tidal pools would have started out fresher, and any rain would have diluted them further.

Even the deep seas, near hydrothermal vents, may not have been too salty for life. Most of the minerals from them, at least today, seem to be compounds of heavier metals.
Shabs42
3.7 / 5 (6) Feb 14, 2012

You mean an unsubstantiated and unproven idea like evolution? And no it has not been proven. All they have found is a bunch of bones that they manipulate to support the evolution theory. Now I am not saying that the earth was created in a day, that makes no sense either. But science must be proven...prove to me that you can evolve a single cell organism into a land walking creature....


Ugh...haven't we gone over this enough? Science emphatically does not have to prove anything. It demonstrates evidence and comes up with theories that best fit that evidence. Evolution is as "proven" as gravity, the periodic table of elements, or that pi is an irrational number.
Deesky
4.5 / 5 (16) Feb 14, 2012
Evolution doesn't take millions to start it off

You're correct, but for the wrong reason. Evolution wasn't a factor in the origin of life. It became important afterwards, once life took hold.

It should be just a chemical mix,but they can't do it.

It's not just a chemical mix, other contributing factors are likely just as important - environmental conditions, energy gradients, mechanical agitation, etc.

Given that we don't know the exact conditions on early earth - the exact environment or the exact physical process taking place, it's little wonder that the few research labs that actually try to do this type of work (generally for short periods of time) have not duplicated life as we know it. The search space is vast, to say the least.

Nevertheless, progress is being made, from understanding the minimum genome for life, to prebiotic chemistry, replicating molecules, lipid/vesicle formation to artificial life and genomes.
Deesky
3.8 / 5 (10) Feb 14, 2012
Can't be that hard to go through all the possible combinations..can it??????

It absolutely can. That's why understanding the areas I've mentioned above will help us to refine and narrow the vast search space.
meBigGuy
3.1 / 5 (7) Feb 14, 2012
One (of many) abiogenesis questions I don't know the answer to is: if self-replicating inorganic molecules are one step to the formation of life, why there are no examples of self-replicating molecules around today (or, are there?).
RealScience
3.9 / 5 (7) Feb 14, 2012
Evolution doesn't take millions to start it off.It should be just a chemical mix,but they can't do it.

Can't be that hard to go through all the possible combinations..can it??????


Life appears to have taken many millions of years to start, in a planet-sized experiment.

Yes, it it would be ridiculously hard to try all of the possible combinations of chemistry. Read up on combinatorics and try the math.

However science has numerous times recreated likely combinations of chemicals and events on a tiny scale, and in doing so they have often produced many of the key building blocks of life.
So there must be many, many combinations of chemicals and energy sources that create such building blocks.
Even the next step of concentrating the building blocks and providing a scaffold for them appears to be accomplished by clays, by mica, by pyrites, by lipid bubbles, and by white-smoker hydro-thermal vents, and probably many other means yet to be discovered.

nkalanaga
3.4 / 5 (5) Feb 15, 2012
meBigGuy: Because any such molecules appearing today would likely be eaten by existing life before they could reproduce.
kochevnik
2.7 / 5 (9) Feb 15, 2012
why there are no examples of self-replicating molecules around today (or, are there?).
They're called catalysts and enzymes. Reproducing the entire engine is a entirely different problem scale. You can't see that looking at one or two molecules. Fundies argue that magic designed the engine and teleported it here on some wind.
Kantfucious
3 / 5 (4) Feb 15, 2012
I find it tough to accept that hot bubbling mud was hot long enough or in the right conditions for the correct chemical combinations to come together and form a cell membrane. Even more mathematically improbable is the assumption that once this membrane assembled itself it allowed the proper chemical inside to create a complex protein. Then this complex protein learned to self replicate. A protein chain as complex as DNA could not just appeared complete and perfect.
Torbjorn_Larsson_OM
5 / 5 (1) Feb 15, 2012
This is worth reading. Geothermal fields have been suggested before, but here is fresher evidence. So as the press release itself notes, material for debate at the very least.

@ nkalagana:

The problem with Monod's "improbable accident" as I understand it, is that it doesn't resemble any stochastic process it speaks about. It sounds more like a model of a vast revisited phase space with a small volume for success.

In a stochastic process sense, the short time to observed first life as well as the predicted average times of diverse abiogenesis scenarios speaks of an easy, frequent and/or successful process. So it would be expected to happen a lot.

After that evolution is contingent, and traits like technological intelligence expected to be exceedingly rare according to most biologists.
Display
1.8 / 5 (10) Feb 15, 2012
Materialism seemed to be an attempt at manipulating objectivity for someones subjective motive. Evolution-Hypothesis is not even a theory. There is nothing scientific in this claim. What a shame!
Torbjorn_Larsson_OM
3.3 / 5 (7) Feb 15, 2012
@ Lurker2358:

[Religious trolling]

The rest of your comment concerns modern life. The paper is research on chemical to biological evolution prerequisites and the pathways up to "emergence of
ion-tight phospholipid membranes."

@ mmead:

Science is not math, it can't be "proven" from assumed axioms since nothing can be assumed. It is based on observation and testing to reject that which isn't the case and which doesn't work.

Biological evolution, which this research doesn't concern as much as prerequisites for chemical evolution, is the best observed fact and its theory the best tested in all of science due to its ubiquiteness and complexity. The most important 30 evidences is described here.
GaryB
3 / 5 (4) Feb 15, 2012
. . .
You mean an unsubstantiated and unproven idea like evolution? And no it has not been proven.


Actually, evolution has been observed both in the lab and in the wild and has multiple converging series of evidence from genetic rates of change, archaic structures, to detailed fossil records, radiocarbon evidence, confirmed prediction and predictable consequences. The mechanisms and code by which life evolves have been found (mutations DNA, RNA) even though early evolutionists had no such data to go on, they posited the mechanism and it was found. Gravity, by comparison is much more mysterious.
Torbjorn_Larsson_OM
3 / 5 (4) Feb 15, 2012
@ mmead:

HTML fail. I'm sure you have been told of Talkorigins, head over there and look up Theobald's review of what evidence the science is based on.
bluehigh
2 / 5 (4) Feb 15, 2012
Can't see any reference to back up the assertion of 'you're correct but for the wrong reason' or your 'absolutely can' type worthless opinion. Still full of yourself and proud of your unsubstantiated negativity, Deesky?
antialias_physorg
3.7 / 5 (6) Feb 15, 2012
Evolution doesn't take millions to start it off

Please revisit your textbooks. The theory of evolution says nothing about how life gets started. It is solely concerned with how life develops thereafter.
Torbjorn_Larsson_OM
5 / 5 (4) Feb 15, 2012
@ meBigGuy:

The trite answer, which already Darwin understood, is that yesterdays organics is todays nutrient. That which formed the first life is used as food today by already existing life, and small molecules will be scavenged before they can build complexity.

More generally, the environment has changed. Chemical evolution needs redox potentials (which later is reproduced in cells during metabolism), and there is much less of them today, fewer heat sources like hydrothermal vents. Most importantly, the modern oxygen atmosphere is a poison for biochemicals and the primordial chemical pathways, the chemicals oxidate quickly and pathways are blocked or diverted.
PS3
1 / 5 (3) Feb 15, 2012
Evolution doesn't take millions to start it off

Please revisit your textbooks. The theory of evolution says nothing about how life gets started. It is solely concerned with how life develops thereafter.

I was merely just bringing it down to the start which matters more if you want to convert everyone.You can't really discuss evolution and say so much without understanding the start.
antialias_physorg
3 / 5 (4) Feb 15, 2012
If you want to talk about the start: Then the current answer is "we don't know"

There are experiments that show you can get complex basic organic compounds (amino acids) from rather simple processes (something we think the ur-atmosphere looked like and an arc of lightning)

But if you think we can already exhaustively replicate all that a planet size laboratory was effectively undergoing for several billion years until the lucky moment happened - then you might think again.
aroc91
5 / 5 (1) Feb 15, 2012
I find it tough to accept that hot bubbling mud was hot long enough or in the right conditions for the correct chemical combinations to come together and form a cell membrane. Even more mathematically improbable is the assumption that once this membrane assembled itself it allowed the proper chemical inside to create a complex protein. Then this complex protein learned to self replicate. A protein chain as complex as DNA could not just appeared complete and perfect.


DNA is not "a protein chain"
Deesky
5 / 5 (3) Feb 15, 2012
But if you think we can already exhaustively replicate all that a planet size laboratory was effectively undergoing for several billion years until the lucky moment happened - then you might think again.

Just a slight correction AP, the 'lucky' moment (I assume you mean first life) didn't take several billion years to occur, but somewhere in the region of 750 million years after earth's formation.
antialias_physorg
4 / 5 (4) Feb 15, 2012
but somewhere in the region of 750 million years after earth's formation.

...if it happened on Earth at all. That's still one of the unknowns. We already know that amino acids are out there in the universe. So who knows where it all started?
http://www.univer...-sample/

Some theories state that life formed in the deep like the bacteria living on radiation. This could have happened even before the planet acquired oceans.
http://www.scienc...ys.shtml

Even if we can replicate a startup self-replicating protein/prion in the lab that won't be any conclusive proof as to whether it started here or not. (Though it would be enormously helpful in establishing THAT it can happen - apart from the obvious technological applications)

That's the thing with singular events: You can simulate them, but as long as you didn't observe them having conclusive evidence is almost impossible to come by.
Deesky
5 / 5 (2) Feb 15, 2012
...if it happened on Earth at all. That's still one of the unknowns.

Sure, but there is no reason why the simplest credible possibility should not be the frontrunner. Either way, it doesn't negate the timeline of when earth's first organisms appeared (or at least left traces of their existence).

So who knows where it all started?


That's the thing with singular events: You can simulate them, but as long as you didn't observe them having conclusive evidence is almost impossible to come by.

The law of parsimony works best when considering varied possibilities, until evidence to the contrary is found.
bluehigh
2 / 5 (4) Feb 17, 2012
Parsimony works when using the least resources just to survive. Get too greedy and bigger bugs will exterminate your species. Growth, propagation or reproduction or even evolution are mostly excluded from parsimonious activity unless you believe in unscientific lucky chances. You are a good example; no prospect of being anything other than a simpleton with dreams of grandeur and likely you will leave nothing but a trace of your developmental failure. Natural selection has a way of dealing with with adaptive failures. How about a new expression for individuals of a species that fail to thrive due to defective adaptation, like the Dodo - its a Deesky.

_nigmatic10
1 / 5 (1) Feb 19, 2012
it began in a primordial soup cup in the middle of a barren plain and it was named Campbell's idiot noodle soup. Some of those noodles still exist today and write articles that make their way to various web sites like this one.
antialias_physorg
3.7 / 5 (3) Feb 19, 2012
One (of many) abiogenesis questions I don't know the answer to is: if self-replicating inorganic molecules are one step to the formation of life, why there are no examples of self-replicating molecules around today

Since we're looking at organic molecules I don't know why there should be self repliating inorganic molecules (remember: 'organic' just means 'contains carbon' - nothing more)

As for organic self replicating stuff: Prions would classify.
PussyCat_Eyes
1.4 / 5 (9) Feb 19, 2012
Hi, I've read all the opinions above this my own post and, as far as my belief on evolution, I think that the conversion of the Earth's atmosphere (from at ground level up to the stratosphere ) from a possible saturation of methane or CO2 or a combination of both plus other gases over a period of a billion years or so, would have forced simple microorganisms to evolve gradually to absorb the newly emerging Oxygen that would have wiped out their predecessors had the Oxygen been emitted into the atmosphere faster rather than a gradual timeline. The adaptation of microorganisms to the gradual replacement of poisonous gases (to us) with Oxygen and Nitrogen etc. would be, IMHO, the best evidence for evolution. There are, of course, other factors to consider that prove evolution occurred and is still occurring, but the adaptation to absorption of the Oxygen was crucial to life continuing and evolving.
camel
1 / 5 (1) Feb 24, 2012

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