For Danmac - Abiogenesis

[Tristesse]

If evolution is true nothing is safe.

What? How is that even logical?

 

[Tristesse]

That's it? You don't know..... At least speculate.

I don't know, is an honest and valid answer. Because saying I don't know means you can continue looking for the answer. Saying magic man did it, means you're done investigating.

 

[Tristesse]

Your in the wrong thread. We are laying the groundwork for evolution in this one. We haven't done that yet, but were working on it.

No, actually we're discussing abiogenesis.

 

[Tristesse]

After we confirm abiogenesis. The baby can't grow until we find out how the baby got here.

The baby got there by reproduction. You know natural processes. Not by magic.

 

[Tristesse]

So you don't know, but your certain God didn't do it, right?

No one is saying god didn't do it. But if you have a claim, you need to support it with evidence, instead of simply asserting it.

 

[DeitySlayer]

The baby got there by reproduction. You know natural processes. Not by magic.

He was trying to be metaphorical and deep about the origin and development of life. But, you know, when you completely lack understanding of the concepts and science that you are attempting to imbue with high-flown langauge, the metaphor sort of :thud:

 

[Autodidact]

That's it? You don't know..... At least speculate.

Well I haven't done a lot of reading about it, and prefer not to speculate without being more informed. If you like I can read up.

I understand that scientists are working on it, and there has been some recent progress, but no clear answer yet. That's all I know.

My guess would be that it's a very gradual transition from something you would not call living, analogous to a virus, to something you would, closer to a cell, with no clear demarcation in between.

 

[Autodidact]

Your in the wrong thread. We are laying the groundwork for evolution in this one. We haven't done that yet, but were working on it.

No, we're not. We're discussing an entirely separate subject, abiogenesis.

It's kinda like how you don't have to figure out embryonic development to study heart disease in middle-aged men.

 

[Autodidact]

After we confirm abiogenesis. The baby can't grow until we find out how the baby got here.

Yes, but we can still study and learn about babies without having to understand conception.

 

[Autodidact]

So you don't know, but your certain God didn't do it, right?

No, Danmac, for the purpose of this thread we're all certain God did do it. The only question is, how.

HOW. HOW. HOW. NOT WHO, HOW.
HOW. HOW.HOW.
What do I have to do to convey this concept to you?

Danmac: What is this thread about? Who created the first life, or how?

 

[Autodidact]

Because we are talking about the beginning of life and how it happened.

Ding! Give Danmac a frubal!!! That's right--how. Get it? How. Your question was about who. We're not asking whether God did it, but HOW he did it. Please try to hold on to this concept until the next page, as I may have to shoot myself if I have to explain it again. Frankly, I've run out of ways to say it.

 

[Tiapan]

Numerous problems exist with the current thinking of RNA as the first genetic material. No plausible prebiotic processes have yet been demonstrated to produce the nucleosides or nucleotides or for efficient two-way nonenzymatic replication. The discovery of the catalytic activity of RNA brought the concept of an RNA world into wide acceptance.

With no predators and half a billion years why does a process have to be efficient? So long as it is 2 way then it can be as inefficient as it likes. Besides where are the authors considerations of silicate array interactions? I am not sure RNA is that catalytic but it can be catalyzed into a polymer fairly easily.

However, the instability of ribose and other sugars, the great difficulty of prebiotic synthesis of the glycosidic bonds of the necessary nucleotides, and the inability to achieve two-way non-enzymatic template polymerizations have raised serious questions about whether RNA could have been the first genetic material, although there are dissenting opinions.

Sugars are simple polyalcohols, hydroxysilyl compounds offer similar bonding solutions but are less mobile or transformable.

Dr. Miller recognized that the RNA world hypothesis was a non-starter. So, he was looking for another way. In his final paper he said,
One proposal offers peptide nucleic acids (PNA) as a possible precursor to RNA because PNA binds DNA and forms double and triple helical structures that are related to the Watson-Crick helix.

There are numerous candidates for polymerised nucleic acid analogs. Which one will be credited as the original will take a while yet. one thing they have in common is the helix structure which is dependent on matching the hydrogen bond pairing, but this is self fullfilling in that incomplete or non matching random pairs will be less stable leading to a predominance of match stable forms.

Peptide nucleic acid (PNA) is a promising precursor to RNA, consisting of N-(2-aminoethyl)glycine (AEG) and the adenine, uracil, guanine, and cytosine-N-acetic acids. However, PNA has not yet been demonstrated to be prebiotic. We show here that AEG is produced directly in electric discharge reactions from CH4, N2, NH3, and H2O. … Preliminary experiments suggest that AEG may polymerize rapidly at 100oC to give the polypeptide backbone of PNA. The ease of synthesis of the components of PNA and possibility of polymerization of AEG reinforce the possibility that PNA may have been the first genetic material.

Quite possibly although it seems a more complicate route, later research appears to be looking at the silicate templates available in just about every square centimeter of the earth

He admits that, “PNA has not yet been demonstrated to be prebiotic.” In other words, there is no evidence that PNA existed before life began. But, for PNA to exist, AEG (and adenine, uracil, guanine, and cytosine) would have had to exist. He was looking for a way to produce AEG naturally as a stepping stone to PNA.

Adenine, uracil, guanine, and cytosine along with a variety of purine and pyrimidine derivatives and precursors were present, also phosphate essential in the process which is inorganic.

In his 1953 experiment, he used an atmosphere consisting of methane, hydrogen, ammonia, and water vapor. In his last reported experiment he substituted nitrogen for hydrogen. That’s reasonable because today’s atmosphere is 79% nitrogen and 0% hydrogen. If the present really is the key to the past, then it is reasonable to assume life began with nitrogen in the atmosphere (and water vapor, too). But the only place you are likely to find methane and ammonia in the air today is near a diaper pail.

I agree the experiment with the nitrogen is closest to earths early environment, hydrogen can escape earths atmosphere. However the Haber process
N2 + 3H2 > 2NH3. requires H2! Lightning can split water into hydrogen and oxygen (the reverse of water formation)
2H2O > 2H2 + O2

So 2N2 + 6H2O > Lightning> 4NH3 + 6O2
then add CO2> amines, imines, nitrogen oxides and other reactive radicals

So all the ingredients are still present just in lower concentrations.

Notice, too, that his simulated atmosphere is still oxygen-free. All origin of life experiments use oxygen-free atmospheres. That, of course, is because oxygen would immediately break down any AEG his experiment produced. The only reason for believing the Earth ever had an oxygen-free environment is because organic compounds could not possibly have originated naturally in the presence of oxygen.

Interesting that the geological evidence shows an early anaerobic atmosphere. I wonder why the author forgot to mention this. Wasnt anaerobic because organic compounds could not originate is totally ignorant taffle.

T
His last experiment showed that a spark in an atmosphere radically different that Earth’s present atmosphere could produce AEG at 100o C (the boiling point of water). He concludes that if AEG existed, it might possibly have helped in the natural formation of PNA, which might somehow have acted sort of like RNA in some sort of unknown replication process. But let us not unfairly put words in his mouth. Here is the concluding paragraph of his last published paper.

It seems we are in agreement that We have an ancient anaerobic atmosphere with lightning capable of producing tonnes of organics every second of everyday for half a billion years so many of the component compounds required were present.
Next the environment. There appear to be 2 main candidates for protolife to occur. One is underwater volcanic vents (HOT) the other is the sea shores (SUNLIGHT) where constant tides and water action promote the diversity of chaos likely to have produced protolife. Organic compounds tend to float on water. attracting other organic molecules including polar ones that tend to stick to them through diffusion forces. If you have ever been to a rugged coast and watched the breakers crash over the rocks producing a spray of fine bubbles each with a little mixture of our primal soup enriched with organics as it is a surface phenomena. One can see in just a few meters literally billions of small micelles form and break. Some last a bit longer than others and oily ones last a long time. So we have an abundance of little isolating containers for lots of micro experiments. Which may be smashed broken and returned to the sea but equally some could be smashed together occasionally combining two different chemistries creating a new combination with useful components which together gradually giving a set that is more likely to proceed than either of its parents. It aso points out that essential systems whose simultaneous appearance in a single micelle is remote the concept that groups with different crucial components could be combined over a long period of time resulting in making the improbable highly probable.

It seems all the pieces of the jigsaw are there, it only remains to postulate the chemical time line and look for the evidence. Two problems organic molecules can be tough but after a couple of billion years they won't be easy to find intact still, second, what we will be looking for may be very, very small.

Remember also during this period there were, by definition, no predatory lifeforms present. so a strong micelles could last indefinitely as the environment was 100% STERILE.
Since a single teaspoon of water can contain around 10^20 molecules of other different substances, we could have 10^19 reactions going on simultaneously every second. In one teaspoon! How many teaspoons are there in the sea? Now multiply that by 500 million years.

Remember we only need ONE to be successful.

Ever taken out a lotto ticket? Notice YOUR odds of winning are tiny, one in millions, yet regular as clock work someone always wins the big prize. Might take a few weeks sometimes but it always goes. It looks like we have a gazillion little experiments occurring constantly over a gazillion seconds of time. Lotto says we win.

Cont....

 

[Tiapan]

Polymerizability and Suitability as the First Genetic Material. The above results show that the components of PNA are likely prebiotic compounds and, under favorable conditions, could be major constituents of the primitive milieu. Still to be worked out are the prebiotic syntheses of the monomers and mechanisms for their polymerization, but prebiotic polymerizations are imposing problems for any potential early genetic system. Our preliminary experiments indicate that AEG polymerizes readily at 100oC to give AEG oligomers and does so much more efficiently than mixtures of -amino acids at higher temperatures. Although PNA also has stability problems of its own, they are highly sequence-dependent and may be alleviated by blocking or acetylating the N terminus. There is also the more difficult problem of PNA replication, which may be complicated by cyclization of the monomers. Nevertheless, this demonstration that the PNA components are prebiotic suggests the possibility that PNA or similar molecules may have been the first genetic material. However, other possibilities need to be considered because there may be other backbones and bases that were more abundant and more efficient for prebiotic replication. 8 Just in case you didn’t follow all that, he found a way to produce AEG which might have allowed PNA to form through a process that is “still to be worked out” in spite of “imposing problems for any potential early genetic system.” But, if it did form naturally it might have disintegrated before it had a chance to replicate because “PNA also has stability problems of its own.” And then, “there is also the more difficult problem of PNA replication.”

Interesting to note that fifty years ago it was not known that cyclic nucleotides are common in primitive procaryotic bacteria. Ever heard of a plasmid?

So, after all that work, Dr. Miller never found what legend says he did—the building blocks of life. Some might say he wasted his whole life on a wild goose chase, but we would disagree. We say that if there had been a wild goose, Dr. Miller would have caught it. He left behind a wonderful legacy of research showing the insurmountable difficulties that prevent life from arising naturally.
Hopefully, years from now, history will correct the errors of the careless popular press. Dr. Miller should not be celebrated for being “the first to demonstrate that the organic molecules necessary for life could be generated in a laboratory flask simulating the primitive Earth's atmosphere.” He should be celebrated for being the one who most conclusively showed that the organic molecules necessary for life could not have been generated in the primitive Earth's atmosphere through his exhaustive research down every blind alley.

I think given the tools and knowledge he had to work with 60 years ago he did remarkably well. However given todays technology his final conclusion may well have been completely different.

Cheers

 

[Runlikethewind]

My guess would be that it's a very gradual transition from something you would not call living, analogous to a virus, to something you would, closer to a cell, with no clear demarcation in between.

Very well put.

 

[Danmac]

Ding! Give Danmac a frubal!!! That's right--how. Get it? How. Your question was about who. We're not asking whether God did it, but HOW he did it. Please try to hold on to this concept until the next page, as I may have to shoot myself if I have to explain it again. Frankly, I've run out of ways to say it.

I checked my frubal count.....you lied

 

[Autodidact]

I didn't say I gave you a frubal, Danmac, I instructed my minions to frubal you. They may have failed to snap to, I don't know.

 

[DeitySlayer]

you lied

I need a new irony meter.

 

[Wotan]

I need a new irony meter.

Poor purchase I think.

It will not last much longer than the other one. Danmac will see to that.

 

[Wotan]

I didn't say I gave you a frubal, Danmac, I instructed my minions to frubal you. They may have failed to snap to, I don't know.

I confess. I just couldn't bring myself to do it. Too many more worthy candidates around.

Appropriate lashes with wet noddle.

 

[Autodidact]

I can haz minyanz?