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Is abiogenesis still happening?

  1. Aug 3, 2010 #1
    Since the process of abiogenesis happened once, I don't see why it shouldn't still be going on. Whatever process formed the first organism billions of years ago could assemble new organisms, completely unrelated to the first organism's "family," right? I don't know much about abiogenesis, so I please share your thoughts on this. I suppose the fact that all species have a common biochemistry would lead most people to argue that only one "family" exists. However, I believe some deep sea microbes have an alternate biochemistry, though I'm sure they still use RNA and DNA with the same nucleotides as DNA and RNA elsewhere.

    Still, for abiogenesis to have only happened once, it must be an event that, statistically, does not occur more often than at least every three or four billion years. And I suppose that could be the case, but I wonder if anyone has explored the possibility that it occurs more often.
     
    Last edited by a moderator: Aug 6, 2010
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  3. Aug 3, 2010 #2

    D H

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    Re: Is biogenesis still happening?

    We don't know how many times abiogenesis happened and failed. We don't know what conditions were needed for abiogenesis to have occurred. We don't have a very good picture yet of how life first arose. Every answer you are going to get is necessarily highly conjectural -- something that generally is looked down upon at this forum.

    You are assuming quite a bit in your statements. You are assuming that the conditions are still ripe for abiogenesis to occur. Conditions on the Earth are quite different now than they were when life first arose. Abiogenesis might only happen on young, hot planets that have a reducing atmosphere, that aren't shielded from high-energy radiation, and that are subject to 100 foot tides. Perhaps life itself closed the door to newly formed life such as by changing the chemical nature of the oceans and the atmosphere. Perhaps the life that evolved from those very first life forms simply gobbled up any Johnny-come-lately life forms.
     
    Last edited by a moderator: Aug 10, 2010
  4. Aug 5, 2010 #3
    Re: Is biogenesis still happening?

    My main reservation on what you did say is that according to the doctrine of microbial infallibility, the word "perhaps" is inappropriate in speaking of the prospects of "Johnny come lately" life forms, or even prebiotic component molecules. Whether they happen to be metabolic detritus, or de novo abiotic molecules, no matter how significant they might have been had they existed 4 billion years ago, they would now be bacteria fodder.
    Anyone doubting this is welcome to produce such a substance, and leave it in the open or underground and see what remains after a few months. And that is just one substance. It takes a lot of substances to make a living entity.
     
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  5. Aug 6, 2010 #4

    Monique

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    I've corrected the use of the term by the OP and the first two responders: the process is abiogenesis, not biogenesis.

    Biogenesis:
    • the synthesis of substances by living organisms.
    • historical the hypothesis that living matter arises only from other living matter.

    Abiogenesis:
    • technical term for spontaneous generation.
     
    Last edited: Aug 10, 2010
  6. Aug 6, 2010 #5

    Borek

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    Where? On Earth? This is tricky.

    First of all, from my understanding of abiogensis, it requires presence of substantial amount of freely available chemicals that can be used as building blocks and food. You can be sure if something like that exists now, it is immediately and efficiently used by organisms already present, not leaving much for abiogesis experiments.

    Additionally, whatever life form emerges from abiogenesis it is initially very vulnerable, it has to evolve all necessary defense mechanisms. That requires time and is unlikely in the presence of zillions of other organisms, that spent last billions of years optimizing their techniques of killing/eating/digesting whatever happens to be around and can be used as a food.
     
  7. Aug 6, 2010 #6

    arildno

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    Take note of what Borek said:
    Life itself chokes opportunities for ongoing abiogenesis.

    Developed organisms are strictly better at consuming food&reproduction than fumbling proto-organisms.

    Natural selection is, largely, an irreversible process, prohibiting re-runs.
     
  8. Aug 9, 2010 #7
    Once again, I have to open a post by acknowledging that I am certainly not claiming to be any kind of expert on the subject. But from engagements I have had on other forums, I would suggest to you that the authority on the subject you have raised here is a man named Tibor Ganti. And here’s the deal – he died just a few months ago. In any case, abiogenesis is something that doesn’t happen today, because the circumstances for it are not right. Earth’s atmosphere is not right for it now. When it was right, it almost certainly happened repeatedly. The overwhelming probability is that many life forms abiogenerated, perhaps even evolved to quite advanced stages, and were then annihilated. It is possible that some modern species are descendants of species that abiogenerated separately from other modern species. But it is also quite possible, maybe even probable, that every modern species is a direct descendant of one single event of abiogenesis. But that certainly does not mean that it only happened once. And it is pretty certain that it doesn’t happen today.
     
  9. Aug 10, 2010 #8
    Monique, you were quite right of course, and in fact I think I was one of the sinners, but what happened to the original thread? I think that much of the substance (terminological infelicities and all) disappeared with it.

    Cheers,

    Jon
     
  10. Aug 10, 2010 #9

    Monique

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    I've reinstated the first two replies, please be more cautious in the future.
     
  11. Aug 10, 2010 #10

    Pythagorean

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    what were conditions like around the estimated time of abiogenesis?
     
  12. Aug 10, 2010 #11

    D H

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    Hot, very hot. It appears life formed rather quickly (geologically speaking) after the surface cooled to below the boiling point. Lots of vulcanism. Huge, huge, huge, absolutely humongously huge tides. No oxygen, a reducing atmosphere, and possibly a very thick atmosphere.
     
  13. Aug 10, 2010 #12
    Thanks Monique.
     
  14. Aug 10, 2010 #13
    There is no way to say "no" with absolute authority, but it seems extraordinarily unlikely that abiogenesis is ongoing. If there were a single area to look at, perhaps deep-sea vents might be the place to look, but this is a bit like saying you should look for bigfoot in the woods. I think such organic molecules would be too vulnerable to the current ocean chemistry; being incorporated into existing inert molecules, broken, or even consumed by existing life.
     
  15. Aug 10, 2010 #14

    Pythagorean

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    Yeah, based on D_H's response, it seems like it's possible that it's going on a bit closer to the center of the Earth where there's a lot of water and lava and pressure (though it may not be comparable to adolescent Gaia. But the common-sense answer seems to be no, of course.
     
  16. Aug 10, 2010 #15

    bobze

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    I'd like to second what others have said. Remember (for the original poster) we are on our third atmosphere here on earth. Life likely arose under the second, which was drastically altered by a metabolic byproduct poison called oxygen, thanks to millions, upon millions of years of the reign of photosynthetic organisms.

    Also, as others voiced, modern organism are just that-modern. Which entails billions of years of evolution at becoming the best energy/food extractors from the environments they exist in. Which includes the really strange places such as undersea vents and deep crust rock.

    I thinks its very unlikely that abiogenesis could occur again (on earth) which such a full and different house now existing here.

    Just my 2 cents
     
  17. Aug 10, 2010 #16

    Pythagorean

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    Never knew there was an intermediary atmosphere. Good point about the competitive organisms down near the lava activity.
     
    Last edited: Aug 10, 2010
  18. Aug 10, 2010 #17

    bobze

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    The first (very short) atmosphere I believe was H and He, but was pretty quickly removed from solar/atmospheric activity.

    The second atmosphere was much heavier with sulfur, nitrogenous compounds (NH3, N2, etc ) and carbon compounds (carbon monoxide/dioxide, mostly I believe).

    That atmosphere was slowly replaced by metabolic respiration (photosynthesis) with the one we have today: though this isn't static, oxygen/carbon ratios as well as temperatures have changed up and down a lot since the Cambrian (which is when animal life really took off).
     
  19. Aug 16, 2010 #18
    It appears it's happened many times, but the new organisms are hardly a match for the older, more advanced ones. Given there are several distinctly different forms of life on earth, with 6 current kingdoms, I suspect that it's happened 2 or 3 times of whose descendants currently exist. Certainly we have eukaryotes and prokaryotes, but we may also have mitocondrion existing as a symbiotic organism in most (though not all) eukaryotes since the latter's own development.

    I'm still waiting for plantman, though perhaps Mr. Bean is indeed a prokaryote, as there's not a lot inside...

    Others argue there are http://en.wikipedia.org/wiki/Three-domain_system" [Broken], the archaea, bacteria, and eukarya, with prokaryota having been split into two distinct groups, the archaea and bacteria.
     
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  20. Oct 11, 2010 #19
    I do recall reading about abiogenesis a very long time ago. Dr. Kenneth R. Miller responded:
    "37. Q&A: How can life come from inanimate matter? (1:25:40)
    Try and move things around. Sir. When do you think that there is gonna be evidence of abiogenesis? When do I think there is gonna be evidence of abiogenesis? Abiogenesis is a term that means life coming from inanimate matter. Well, depends what you mean by that. Some people would say that abiogenesis took place about 10 years ago and it was 10 years ago, little more than 10 years ago, I think, when scientists took chemicals off the shelf, put them into DNA synthesizers, synthesized the DNA molecule of a virus and then were able to reconstruct a virus particle. So if you consider viruses to be living, that's abiogenesis. A very well-known scientist, Craig Venter, who worked on the Human Genome Project, is now trying to do exactly the same thing with a real cell, not a virus, a bacterium, trying to construct a minimal organism. Knowing this guy, within a few years he's probably gonna succeed. So that sort of ability to take nonliving chemicals and put them and make them come alive by mimicking the living cell, I think that's pretty close. The larger question that I think you're asking is how soon is it going to be that we will have an answer to the riddle of how the first living cell originated from nonliving chemicals on this planet? I am not optimistic that it's gonna happen anytime soon. And the reason for that is, happened a long time ago and it didn't leave much evidence, but there are a number of researchers who have put together pieces of the puzzle and I am certainly confident that that's exactly how it took place. Jack Szostak at Harvard has done some absolutely brilliant work that involves self-replicating RNA molecules and the simulations of conditions on the primitive earth, so I certainly think that it happened that way, but in terms of achieving a total understanding I think we're a couple of decades away from really understanding how life originated on this earth. Good question. Thanks for your attention. Thanks for the opportunity." (Howard Hughes Medical Institute, Dr. Kenneth R. Miller, Evolution: Fossils, Genes, and Mousetraps (2006)
    http://www.hhmi.org/biointeractive/dvd/transcripts/Ken Miller Evolution Lecture Transcript.pdf )
     
    Last edited: Oct 11, 2010
  21. Oct 11, 2010 #20
    Known Physics and Chemistry is defeated and rewritten everyday. I'm not saying that clouds are alive or not, I just feel if we ignore new ideas because we know old answers we have lost our ability to see what is possible. I myself have read about the building blocks of life since the 1960's. Reading that so many things in life are "proven" to be so very common is interesting but all the mixing, cooking, shocking, and eradication has only proved we no nothing about how life started. If by chance someone builds a basic lifeform this week will they really have proved that was how live began? "How can life come from inanimate matter?" Live might not be so complex and it just might be more common then our minds can allow.
     
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