Chemical Evolution in the Early Ocean

[Ophiolite]

Geistkeisel, it is apparent that English is not your native language. As someone who has been unsuccessful in multiple attempts to learn a foreign language I am in awe of those who are bi-lingual or even multi-lingual. Could I humbly recommend that you use shorter sentences in future. This should help make your posts more intelligible to the rest of us and thus enable us to share your thoughts.

 

[geistkiesel]

Geistkeisel, it is apparent that English is not your native language. As someone who has been unsuccessful in multiple attempts to learn a foreign language I am in awe of those who are bi-lingual or even multi-lingual. Could I humbly recommend that you use shorter sentences in future. This should help make your posts more intelligible to the rest of us and thus enable us to share your thoughts.

I am trying Ophiolite. I think I have an excess (and more often unnecessary) of desire for completness and, not surprising, I understand what I write, yet I realize from your kind post, and others ,that I have "problem".

BTW English is my first language. The story gets sadder all the time doesn't it O?

Thanks,
Geistkiesel.

 

[Ophiolite]

Oops. Ophiolite retreats in embarassment. Didn't mean to give offence Geistkeissel. Unwarranted assumption based in part upon your name. I see that you have the same difficulty in writing that I have in speech. For me the benefits of writing is that one can edit. Once the words have left the lips however, that is that. So one indulges in post speech editing, i.e. more words, and on it spins into confusion and oblivion.

 

[Emmveepee]

In order for life to form there must be large oceans of water upon the planet.

In order to form life as we know it.

 

[Erring Flatley]

In doing a library search I have found that others before me have thought of the idea. One paper on the subject is: Mercer-Smith, J. and Mauzerall, D.C. 1984 Photochemistry of porphyrins: a model for the origen of photosynthesis. Photochemistry and photobiology 39, 397-405. I will return with more citations in a while as if there is a single interested serious individual out there.

 

[Erring Flatley]

In order to form life as we know it.

I looks like one is interested, maybe. I cannot imagin any other way for life to begin. Carbon is the only element capable of supporting life. Science fictionists cite silicon but silicon dioxide is not in a gas or soluble form and that is a necessity for life chemistry. For life on other planets, I am sure it started with a porphyrin ring in a large optically pumped ocean. Evolution beyond that may be different, but there are only so many ways atoms can be put together that make a successful organism.

 

[geistkiesel]

Oops. Ophiolite retreats in embarassment. Didn't mean to give offence Geistkeissel. Unwarranted assumption based in part upon your name. I see that you have the same difficulty in writing that I have in speech. For me the benefits of writing is that one can edit. Once the words have left the lips however, that is that. So one indulges in post speech editing, i.e. more words, and on it spins into confusion and oblivion.

Opiolite, mon cher, no embarrassment earned or warranted. If I had felt more than the few dozen or so tears that squezzed painfully from my eyes and shuddering body you would have received a secret missive, full of spite and rancor - pages and pages of advice..

"The moving finger writes and having writ does not move on , for with all your piety and wit ye may lure it back to cancel half a line."

The speech thing is not that difficlt to tame, your mind is just going so fast the words dump out without filter. "You just don't reaize how fucking smart you are and the words spew out like water from a fire hose. You just talk too much; take the smallest split second and listen to yourself before you let go." This I told a shocked, but not negatively insulted woman once upon a long time ago. Overall she seemed grateful. I thought we ended up as 'bonded.' Obla dee bal dah.

Have you ever considered that you really don't know specifically what the next word or words are going to be in nonrehearsed converstaion? I mean, even practiced as dramatic speech, speaking or writing, the words are suspended in quietude,real and working only when the throat is vibrating.

With this is the reflected corrollary: you do anticipate something like the quietude above when listening, or reading; is it not natural and easy to stay ahead of the speaker a few words, in general, knowing but not hearing?. Think about it.

BTW I lived in Germany for three years as a child 9 - 13. No vertlich, really, I was once a child. Can you dig it?

Thanks Big O. I think we are near the same age.

Geiskiesel

 

[geistkiesel]

I looks like one is interested, maybe. I cannot imagin any other way for life to begin. Carbon is the only element capable of supporting life. Science fictionists cite silicon but silicon dioxide is not in a gas or soluble form and that is a necessity for life chemistry. For life on other planets, I am sure it started with a porphyrin ring in a large optically pumped ocean. Evolution beyond that may be different, but there are only so many ways atoms can be put together that make a successful organism.

Mr. Flately,
There is the story of a well known and respected biology house, in Sicily, if I remember correctly, that had a continuous experiment going. Large aluminum jugs containing various chemicals and elements necessary for producing amino acids etc were hooked intricately together. The various mixtures were given occasional jolts of electricity, heat, cold, whatever, and once a week the manager of the project would come around, lift the lid on the main cannister and ask: "Is anybody there?"

Geistkiesel

 

[sideshowbob]

I looks like one is interested, maybe.

I was interested last week, but you wouldn't talk to me rationally.

I cannot imagin any other way for life to begin.

Science is not about imagination. It is about observing and making inferences based on those observations.

Carbon is the only element capable of supporting life. Science fictionists cite silicon but silicon dioxide is not in a gas or soluble form and that is a necessity for life chemistry.

Life as we know it requires carbon. Why would silicon-based life require silicon dioxide, specifically, and why does it matter if it's in gaseous or soluble form?

... there are only so many ways atoms can be put together that make a successful organism.

If there are "so many ways", have you considered them all?

You started with an opening post that made a lot of assumptions about how life "must" have started, but you make little or no attempt to justify those assumptions. Does taking an interest in the subject constitute swallowing everything you say, hook, line and sinker, without question?

 

[Hercules Rockefeller]

In order for life to form there must be large oceans of water upon the planet.

We don’t even know that for sure. There is a theory growing in popularity that says that the first cells arose not in the oceans but deep in subterranean rock where they were protected from the constant meteorite impacts that occurred following the formation of the Solar System. These impacts were massive and would routinely vaporize Earth’s oceans. But deep down in Earth’s crust there are little pockets of water that were protected from such impacts. The theory says that anaerobic thermophilic bacteria arose in these little pockets aided by certain mineral compounds that lined the pockets and acted as artificial cell membranes. (I don’t remember what these minerals are.) There are endogenous bacteria in the Earth’s crust as far down as we are able to drill, and they are members of the Archea – the oldest known life forms on the planet.<P>

 

[nero]

Could you please explain the oceans on Earth, Mr HR

they would provide a lovely place for living cells....... better than down deep locked in rock
Ha Ha

where you been living?

 

[Hercules Rockefeller]

Could you please explain the oceans on Earth, Mr HR

What aspect of oceans on Earth needs explanation?

they would provide a lovely place for living cells

Maybe, except for the fact that 4 billion years ago (around the time that the first cells are thought to have arisen) there were regular massive meteorite impacts that super-heated and/or vaporized the oceans. Not that lovely I would have thought......

better than down deep locked in rock

Define “better”. Why “better”? What you would regard as a “better” environment has nothing whatsoever to do with the environments in which bacteria live. Archaebacteria can thrive in extremes of heat and cold, and in noxious environments. Like I said, there are endogenous bacteria in the Earth’s crust as far down as we are able to drill. That’s their normal environment.

Ha Ha

What’s funny?

where you been living?

Relevance?<P>

 

[Ophiolite]

Could you please explain the oceans on Earth, Mr HR

they would provide a lovely place for living cells....... better than down deep locked in rock
Ha Ha

where you been living?

It is rather clear nero, that HR has been living closer to current, informed scientific research results than your have been. He has also been living closer to well mannered society. This has inhibited him from calling you an ignorant, ill-mannered, semi-literate troll.

 

[Hercules Rockefeller]

This has inhibited him from calling you an ignorant, ill-mannered, semi-literate troll.

Actually, Ophiolite, if "nero" is who I think he is, then I have called him those things many times on another forum! (A forum where I believe he was recently moderated for trolling.) <P>

 

[Raithere]

In order for life to form there must be large oceans of water upon the planet. This is a necessity for chemical evolution.

As has been pointed out this is not agreed upon. There are a number of abiogenetic hypotheses that do not require oceans.

Once such light absorbing catalyzing chemicals formed, they multiplied forming their precursors and mutually supplying each other the lesser molecules to form the higher molecules. In effect the entire ocean become like a giant primitive cell.

Can you define this mutually supporting system beyond a vague generalization? This sounds mostly like wishful thinking.

At one point porphyrin rings formed and were the most successful of this type of self replicating molecule.

Porphyrin rings do not self-replicate. They form naturally.

Such molecular groups are called micelles. Amino acids incorporated into the wall of the micelle. Again they are a chance occurrence of photon-catalytically created molecules. Amino acids are polar and easily combine into the wall of a mycell. In the next step of chemical evolution, these amino acids became peptides associated with the energy absorption of the porphyrin ring and helped to catalyze chemical reactions. Gradually they evolved into the protein enzymes we know today.

Micelles do not self-replicate either. So far you're asserting that two types of molecules with no ability to self-replicate or pass on heritable information somehow evolved. The more likely scenario is that RNA or some precursor to RNA developed within or was in some other way incorporated into the environment provided by such structures.

~Raithere

 

[Erring Flatley]

As has been pointed out this is not agreed upon. There are a number of abiogenetic hypotheses that do not require oceans.

Can you define this mutually supporting system beyond a vague generalization? This sounds mostly like wishful thinking.

Porphyrin rings do not self-replicate. They form naturally.

Micelles do not self-replicate either. So far you're asserting that two types of molecules with no ability to self-replicate or pass on heritable information somehow evolved. The more likely scenario is that RNA or some precursor to RNA developed within or was in some other way incorporated into the environment provided by such structures.

~Raithere

Micelles do self-replicate. If soap is dissolved in water it forms mycelles. The size of the micelles is deturmined by the size of the soap molecule. Larger micelles are unstable and fall in two. If a micelle grows in size it becomes unstable and divides. Other soap-like molecules do this as well.

In the early ocean there was a large amount of dissolved chemicals and it was sharply acidic from dissolved volcanic gases, unlike the ocean of today which is scrubbed biologically by filter feeders. Porphyrins are a tetrapyrrol. That is they are a four sided ring composed of four pyrrol molecules. A pyrrol molecule is a five sided ring containing one nitrogen and four carbons. It is conjugated, meaning it has double bonds alternating with single bonds. Porphyrin is conjugated as well. This conjugation allows for an electron cloud structure that easily shifts electrons from one atom to another, simular to the ways electrons shift in a metal. Because pyrols are such simple molecules it is sure they occured by chance in large numbers in the early ocean. And, they are acid stable. It is highly likely that four of these accidentally formed a porphyrin ring, which is also highly stable in acids. Porphyrin rings with a metalic ion in their center easily absorb light, as we know. And, they have the ability to pass on the excited electron to an acceptor molecule, putting the acceptor into an excited state capable of forming new molecules of a more complex state. Early porphyrin rings easily catalyzed chemical reactions that formed precussors to porphyrin rings and then porphyrin rings. Early porphyrin were capable of self replication.

Life without water as a solvent is impossible. Early life had to have evolved in an aqueous environment. Life without an energy source is impossible. Light is the energy source upon which our life is based. The early ocean was both aqueous and bathed in light. The early ocean is where life on earth evolved. And porphyrins were a step in chemical evolution leading to biological evolution.

Additionally, there are geologically early slates and shales, which are both formed from mud sediments, that contain high concentrations of porphyrins, showing these slates and shales are the repository of porphyrins sedimented from the early ocean.

 

[flyboytim]

"The early ocean was... bathed in light."

Not really very likely with all that active vulcanism, regular meteoric impacts, constant boiling acid rain onto hot newly solidified metal-rich rocks.

A bit like the British weather at this time of the year, very dull, except when it gets dark, and hot rather than freezing.

Try chemoautotrophs rather than photoautotrophs, they fit the bill much better, and work better in the dark, and all the sulphur they excrete is ideal to mop up all those nasty toxic metal ions dissoved in the acid, which have a way of poisoning organisms - often by hijacking the active sites in porphyrin rings.

 

[Erring Flatley]

"The early ocean was... bathed in light."

Not really very likely with all that active vulcanism, regular meteoric impacts, constant boiling acid rain onto hot newly solidified metal-rich rocks.

A bit like the British weather at this time of the year, very dull, except when it gets dark, and hot rather than freezing.

Try chemoautotrophs rather than photoautotrophs, they fit the bill much better, and work better in the dark, and all the sulphur they excrete is ideal to mop up all those nasty toxic metal ions dissoved in the acid, which have a way of poisoning organisms - often by hijacking the active sites in porphyrin rings.

Chemoautotrophs, which are much more complex than porphyrins, came later. Chemoautotrophs contain porphyrins. Chemoautotrophs are decended from porphyrins. Light, even filtered through clouds, is a far more substantial source of energy than the chemicals coming out of volcanoes, particularly given how oxidized those chemicals are. Oceans did not form until the crust was well cooled. The ocean was vapor before that. Heat of the crust is not a factor. Life is based on the energy of the sun now and obviously has been for most of evolution and our life must be decended from organisms that used light or relied upon organisms that used light, for their energy. As I said earlier, the differentiation of animal from plant occured during the porphyrin stage of evolution. And, at that time, the ocean was more like one large cell. All the chemicals disolved in the ocean were involved meaning SH2 and other chemicals used by chemoautotrophs. Evolution of porphyrin chemical forms was happening at that time. There was a multitude of porphyrin forms occuring and competing at that time. The line of porphyrins that led to animals did indeed metabolize energy containing chemicals. But those chemicals were by and large the chemical remains of destructed photosynthetic porphyrins. Porphyrin life was so dominant at that time that the geological record from that time is almost saturated with porphyrins. Shale deposites, the metamorphic rock of mud, contain large amounts of porphyrins, obvously sedimented from the early ocean.

To illustrate how far back the evolution of porphyrins go, it has been found that the chemical structure of myoglobin in vertebrates is simular to the chemical structure of leghemoglobin in the bacteroids of nitrogen fixing nodules in soybeans. Those are two very different branches of the phylogenetic tree. (Ellfolk, N. 1972. Leghemoglobin, a plant hemoglobin. Endeavour 31: 139-142)

 

[Ophiolite]

Nobody doubts the importance of porphyrins in biology. That is quite different, however, from claiming that they lie at the root of the origin of life. This is what you appear to be claiming.
Again, it is reasonable to expect that various developments [some might call them evolution] of organic chemicals would occur at the pre-biotic stages of the emergence of life. However, in what way did the porphyrins give rise to RNA or DNA? If you cannot provide that link then your argument appears wholly flawed.

Secondly, it is very difficult to determine what you actually are saying. This is a science forum not a site for creative writing. State your theme in summary, then expand on the details and present your conclusion. Don't dribble the information in from post to post in an apparently disconnected fashion.

And lose the big blue font, why don't you.

 

[Raithere]

Micelles do self-replicate. If soap is dissolved in water it forms mycelles. The size of the micelles is deturmined by the size of the soap molecule. Larger micelles are unstable and fall in two. If a micelle grows in size it becomes unstable and divides. Other soap-like molecules do this as well.

This is not self-replication; this is just the physics of surface tension.

Early porphyrin rings easily catalyzed chemical reactions that formed precussors to porphyrin rings and then porphyrin rings. Early porphyrin were capable of self replication.

Do you have any studies where they were actually successful in developing a self-replicating system? The closest I found was this:

http://www.ncbi.nlm.nih.gov/entrez/...ve&db=PubMed&list_uids=12926398&dopt=Abstract

Life without water as a solvent is impossible. Early life had to have evolved in an aqueous environment.

Life, as we know it, requires liquid water. Gotta be careful with words like "impossible".

Life without an energy source is impossible. Light is the energy source upon which our life is based.

Not all life on Earth requires light as its ultimate energy source. There are entire ecosystems in the ocean depths that are able to harness geothermal energy. There are also bacteria that subsist solely off of chemical energy.

The early ocean was both aqueous and bathed in light. The early ocean is where life on earth evolved. And porphyrins were a step in chemical evolution leading to biological evolution.

It is a possible scenario, yes. Proven; no. I don't have as much a problem with the theory here as with your emphatic assertion.

~Raithere