Why did abiogenesis stop producing life forms,and at what point do you think it stopped?

Darwin, in a personal letter (not in his actual books or theory), gave us one big reason ...

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“It is often said that all the conditions for the first production of a living organism are now present, which could ever have been present. But if (and oh what a big if) we could conceive in some warm little pond with all sorts of ammonia and phosphoric salts, light, heat, electricity, etc., present, that a protein compound was chemically formed, ready to undergo still more complex changes, at the present day such matter would be instantly devoured, or absorbed, which would not have been the case before living creatures were formed.”

(Darwin, C., 1871, Letter to Hooker. Reproduced in Calvin, M. (1969). Chemical Evolution pp 1-8. Oxford University Press, London: as quoted in “Did minerals perform prebiotic combinatorial chemistry?”, Alan W. Schwartz, Chemistry & Biology 1996, 3:515-518).

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The origin of life on Earth would have required the accumulation and complexification of organic compounds, over the course of millions, tens of millions, or hundreds of millions of years. But once life existed, it would be there to feed on accumulating organic compounds, preventing them from accumulating and complexifying.

The first life was not photosynthetic (extracting energy from light), nor was it able to digest other living things (because there were none around to digest). They were chemotrophs. that is, they had to be able to extract both raw materials for their reproduction and the energy to accomplish all the processes of living by inducing energy releasing chemical reactions of stuff in their environment.

The details are way out of my area of specialization and educational background, but I can recommend a very readable book devoted to this story and what we (the biochemists among us) have so far decoded and pieced together (which is quite a lot, actually).

If you would actually like to learn some real and amazing stuff about this subject instead of trying to stump atheists, I suggest you buy or borrow a copy of:

Tracing the History of Eukaryotic Cells: The Enigmatic Smile

by Betsey Dexter Dyer and Robert Alan Obar

http://product.half.ebay.com/_W0QQcpidZ84656QQprZ7...

By the way, the Enigmatic Smile refers to the Cheshire Cat character in the Through the Looking Glass (Alice in Wonderland) story. You will have to read the book to find out how that connects to your question. But be prepared to have your mind rearranged, a bit.

Sorry, I missed your Cheshire Cat smile. Just another little bit of universal sychronicity.

http://en.wikipedia.org/wiki/Synchronicity

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Regards,

John Popelish

Abiogenesis is like freezing water, so long as the conditions are met water will freeze, its not as though abiogenesis some how "willfully" stopped, the conditions on earth simply stopped being favorable for such chemical processes to continue. there are several lines of evidence to show us that the earth was in fact different in the distant past, look up ice core samples for starters.

secondly we know that life had to have had a start, so the question is how do we explain it and what do we base this explanation on? do we base it on the evidence that we can gather or do we simply use the pre-scientific explanations that religion enforces through dogma?

Yours is a very good question, but remember "belief" has no place in science. Belief is to accept something without evidence, like belief in god or demons or santa claus.

Abiogenesis has not been proven to have happened and every good biologist will tell you that. But if it did happen once, why does it not continue to happen? Probably because the life here already just swamps it out. Abiogenesis would be a very slow process, so if it began again today, existing life would likely destroy it. If it occurred in a place where no life occurs now, like 10 miles down in the earth's crust, it might have a chance.

a) At the point at which living things became commonplace and started secreting enzymes into the environment to digest up biologically useful molecules

b) At the time of the Oxygen Catastrophe. Oxygen would combine with molecules in the environment, preventing the formation of big organics.