Primordial soup

[deltanova]

does anyone have any good links for info on primordial soup????

[MolecularMan14]

http://leiwenwu.tripod.com/primordials.htm

[Dov]

Yes, it'd be interesting to make a fresh mix and start all over again...

[MolecularMan14]

lol, true. I would love to observe some of the earliest, most primitive life forms, and compare them to their closest genetic cousins of today. Just to track the evolution. Then again, there would be no garuntee that something would develop the same.

[YT2095]

wasn`t there some kind of experiment done using salt water and a mixture of different gasses in a sterilised jar that an electric discharge was put through, and it resulted in the formation of basic Amino acids?

 

I`m fairly sure it`s a true story.

[MolecularMan14]

wow, I would love to see the results of that kinda thing. What was the outcome?

[YT2095]

IIRC it produced several Amino acids, as you already probably know, they are the basic building blocks of life. I think methane and nitrogen gasses were present as well as O2 traces, but I don`t rem all the details, sorry

[coquina]

http://www.pbs.org/wgbh/aso/databank/entries/do53am.html

Stanley Miller (b. 1930) was a doctoral student working with Urey at the University of Chicago, researching possible environments of early Earth. In 1953 he combined the ideas of Urey and Oparin in a short, simple experiment.

 

He reproduced the early atmosphere of Earth that Urey proposed by creating a chamber with only hydrogen, water, methane, and ammonia. To speed up "geologic time" in his experiment, he boiled the water and instead of exposing the mix to ultraviolet light he used an electric discharge something like lightning. After just a week, Miller had a residue of compounds settled in his system. He analyzed them and the results were electrifying: Organic compounds had been formed, most notably some of the "building blocks of life," amino acids. Amino acids are necessary to form proteins which themselves form the structure of cells and play important roles in the biochemical reactions life requires. Miller found the amino acids glycine, alanine, aspartic and glutamic acid, and others. Fifteen percent of the carbon from the methane had been combined into organic compounds. As amazing as discovering amino acids at all was how easily they had formed.

 

[Sorcerer]

Yeah, his experiment assumes that the earth's atmosphere was reducing, not a bad assumption, considering we can attribute almost all the oxygen in the atmosphere to photosynthesis, which came much later.

 

There are other theories for chemical evolution, a couple I like are:

 

Intersellar seeding; this doesn't necessarily mean fully developed life arrived here, but just means organic molecules needed for building life were synthesised in space and brought here after the earth formed by comets/asteroids/space dust. The main problem with this is that UV light in space would break apart complex molecules, which is why they would need to be sheltered within a body, eg large comet/asteroid/cloud of dust. Incidentally the same thing applies here on earth, and Miller's experiment doesn't add UV light, but CH4 and NH3 are good at absorbing UV wavelengths, possibly providing some protection.

 

Deep-sea vents have always seemed to me to be a better candidate than atmospheric chemical evolution, as if removes the UV problem, theres a great source of energy and alot of different chemicals in water. Also some archeobacter species live around these vents today, they metabolise sulphur and as such would be a good candidate for something like the first life-forms because photosynthesis came later, and there wasn't any other life to prey on.

 

By the way it shouldn't be overlooked that theres a huge leap from amino acids to proteins not to mention how it got to RNA then to DNA. Supposedly amino acid containing solution washed up onto hot clay can polymerise them and form proteins. Its speculated that proteins which acted like prions and catalysed the formation of RNA bases were what kick started life.

[deltanova]

hmm, how would it work if you got a sterilised infiroment, (sand, rock,) put it into an atmospheric dome with a pond or pool in the middle, (to represent the sea floor, beach, ect.) and mix in all the known respective (or closest) chemicals into the sand, water and atmosphere, and see what happens, as stuff dies it floats to the floor and gives other stuff more reason and ability to develop by the organic material build up ( i realise this is impossible, good to think about but, maby it would be a good experiment for when we put a research colony on the moon?)

[Sorcerer]

hmm, how would it work if you got a sterilised infiroment, (sand, rock,) put it into an atmospheric dome with a pond or pool in the middle, (to represent the sea floor, beach, ect.) and mix in all the known respective (or closest) chemicals into the sand, water and atmosphere, and see what happens, as stuff dies it floats to the floor and gives other stuff more reason and ability to develop by the organic material build up ( i realise this is impossible, good to think about but, maby it would be a good experiment for when we put a research colony on the moon?)

 

The problem is that the early earth was a far more chaotic environment than just water and sand, huge tectonic forces were creating massive clouds of dust and gas in the atmosphere sheilding out the sun, there were very fractured plates and a large ammount of subduction and conversion zones, we were being bombarded almost constantly by meteors and comets.... some think that these actually seeded the earth with some of the chemicals needed for life, some actually think they couldve brought life here already formed.

 

As far as hypotheses about the chemical origin of life go, I prefer mixed ones, in some places amino acids were made, in others lipid membranes, I think proteins wouldve been the starting blocks, prion-like they would conserve their shape and influence the shape of others, if they gained the ability to catalyse the sythesis of RNA nucleotides and their polymerisation into chains, it would only be a matter of time b4 the right combination was hit on which produced the protein that did this itself, and also RNA codes which Ribosome like proteins, thus enhancing the rate of the cycle and allowing even more variation to occur while conserving the already successful Ribosomal protein and nucleotide sythesis codes... once these ribosomes were assimilated into a lipid membrane, this formed protobionts, basically all is needed from here to life is ion channels and DNA.... DNA didnt have to come untill much later when UV levels became intolerable as the atmostphere cleared, this is because DNA is more stable than RNA.... at this point DNA would contain double strandedness and hence copy proteciton.