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How common is abiogenesis?

Was our abiogenisis a multiple event? When will abiogenesis be replicated in the laboratory?

Posted: September 6th 2008

George Locke

How frequently does abiogenesis occur? Let’s make some rough estimates using available figures.

A quick trip to wikipedia will indicate that life began roughly a billion years after the earth coalesced, perhaps more. Even if only a small fraction (1%) at the end of this period was climatically suitable for abiogenesis, this is still ten million years. So we can roughly estimate an upper bound on the frequency of abiogenesis at once every ten million years. This is indeed a very rough estimate, and there may have been additional abiogenesis events that were unsuccessful or were wiped out by our ancestors. But we’re just looking for ball-park figures, so I think we’re still okay.

One should note that my estimate for the frequency of abiogenesis considered the rate for abiogenesis to occur anywhere on the planet. Consider a possible experiment that completely removed all living things from a square kilometer of ocean. (This is of course practically impossible but should illustrate the point.) The surface area of earth is 510,065,600 square kilometers, roughly two thirds of which is ocean, or 340,043,733 square kilometers. So our experiment occupies about 3 billionths (0.0000003%) of the available ocean. So we can expect the rate of abiogenesis observed by this experiment to be three billionths of the rate of abiogenesis that occurs naturally worldwide.

In other words, even with this very favorable estimate for the wordlwide rate of abiogenesis and an impossibly sensitive experiment, the chance of an abiogenesis event to be observed in a hundred years is orders of magnitude less than one in a trillion.

Consider now that any practical experiment would not take place in a square kilometer of ocean, but in a laboratory. Consider that abionenesis events that were to occur might not be easily identified. Consider that a hundred year experiment is not very likely. Of course, experimenters are clever and they might somehow boost the rate of abiogenesis. Even in the above hypothetical experiment, if they boosted the rate by a million times then the chances to observe abiogenesis are still less than one in a million.

I think it’s easy to see that we shouldn’t expect abiogenesis to be observed in a lab for a very long time.

Posted: September 16th 2008

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Reed Braden www

All life that we know of on this planet came from one abiogenesis event. There may have been others that weren’t as successful. It is also very likely, so likely that I would say definite if it didn’t make certain people cringe, that abiogenesis has happened over and over again in our galaxy and maybe even our solar system.

It probably won’t be reproduced any time soon. To most people, there isn’t as much benefit in such an experiment as, say, finding the Higgs Boson.

Posted: September 16th 2008

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SmartLX www

The DNA shared by all life on the planet shows that it has a single common ancestor. Therefore we are all products of a single abiogenesis event.

That doesn’t mean it was the only abiogenesis that ever happened. When an area of swamp or moist clay reached the right conditions for it to occur, it’s possible that it happened all over that area. Darwinian natural selection would have immediately occurred as the proto-organism which replicated most effectively starved the others of space with copies of itself. Maybe it even ate the others. Free from living competition, our ancestor could multiply and diversify in a slightly more friendly environment.

It’s also possible that abiogenesis occurred independently in many places around the world, probably at about the same time. Assuming none of the other unrelated life forms are still around waiting to be discovered, if they ever existed they didn’t survive for long enough to leave visible evidence that they were ever there. Our ancestors were the fortunate ones.

There have been experiments since the sixties reproducing various aspects of abiogenesis. Even then they managed to create amino acids using only prehistoric atmosphere and lightning. Amino acids aren’t alive, but they’re a critical part of all life.

No one can say when the complete process will occur in a lab, but all it would take is the right scientist with the right idea.

Posted: September 15th 2008

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