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  1. #1 Common Ancestor 
    Forum Radioactive Isotope zinjanthropos's Avatar
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    When I read that all living things share a common ancestor, is it referring to just one single organism? My thinking is that around the same time when conditions were right for this organism to form then was there a chance that many more just like it also came to be?

    I really don't like the chances of survival if it was only a single organism but if there were countless many formed at the same time then the odds would improve. My thinking is that the common ancestor was not a one and only.


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    Quote Originally Posted by zinjanthropos View Post
    When I read that all living things share a common ancestor, is it referring to just one single organism? My thinking is that around the same time when conditions were right for this organism to form then was there a chance that many more just like it also came to be?

    I really don't like the chances of survival if it was only a single organism but if there were countless many formed at the same time then the odds would improve. My thinking is that the common ancestor was not a one and only.
    I think it means an ancestor population rather than an individual organism.

    For instance, regarding Man, nobody apart from some varieties of Christian denomination, thinks there were literally two people (Adam and Eve, effectively) from whom all homo sapiens is descended. It will have been a population, part of which evolved towards something different, until the differences became too great for interbreeding to be fertile any more, thus creating a new species.


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    Forum Radioactive Isotope zinjanthropos's Avatar
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    Quote Originally Posted by exchemist View Post
    Quote Originally Posted by zinjanthropos View Post
    When I read that all living things share a common ancestor, is it referring to just one single organism? My thinking is that around the same time when conditions were right for this organism to form then was there a chance that many more just like it also came to be?

    I really don't like the chances of survival if it was only a single organism but if there were countless many formed at the same time then the odds would improve. My thinking is that the common ancestor was not a one and only.
    I think it means an ancestor population rather than an individual organism.

    For instance, regarding Man, nobody apart from some varieties of Christian denomination, thinks there were literally two people (Adam and Eve, effectively) from whom all homo sapiens is descended. It will have been a population, part of which evolved towards something different, until the differences became too great for interbreeding to be fertile any more, thus creating a new species.
    Exchem: thanks for providing input to my questions.

    Would it be safe to say the common ancestor population grew from a very hostile environment? I'm thinking this was what confronted the common ancestor population. Is it logical to assume it's fact, or makes no difference that an organism's chances of surviving/evolving/adapting are greater when moving from a hostile to a less hostile environment?
    All that belongs to human understanding, in this deep ignorance and obscurity, is to be skeptical, or at least cautious; and not to admit of any hypothesis, whatsoever; much less, of any which is supported by no appearance of probability...Hume
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  5. #4  
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    Quote Originally Posted by zinjanthropos View Post
    Quote Originally Posted by exchemist View Post

    I think it means an ancestor population rather than an individual organism.

    For instance, regarding Man, nobody apart from some varieties of Christian denomination, thinks there were literally two people (Adam and Eve, effectively) from whom all homo sapiens is descended. It will have been a population, part of which evolved towards something different, until the differences became too great for interbreeding to be fertile any more, thus creating a new species.
    Exchem: thanks for providing input to my questions.

    Would it be safe to say the common ancestor population grew from a very hostile environment? I'm thinking this was what confronted the common ancestor population. Is it logical to assume it's fact, or makes no difference that an organism's chances of surviving/evolving/adapting are greater when moving from a hostile to a less hostile environment?
    I'm far from expert on this but I don't see why the environment need be hostile. As I understand it, the mechanism is more reproductive success for organisms that are better adapted to the environment. I can imagine that the adaptation might be such as to overcome something hostile, or it might be something better able to make use of the available nutrients, or faster reproduction, or anything else that could improve reproductive success.
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    Forum Radioactive Isotope zinjanthropos's Avatar
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    Quote Originally Posted by exchemist View Post
    I'm far from expert on this but I don't see why the environment need be hostile. As I understand it, the mechanism is more reproductive success for organisms that are better adapted to the environment. I can imagine that the adaptation might be such as to overcome something hostile, or it might be something better able to make use of the available nutrients, or faster reproduction, or anything else that could improve reproductive success.
    i drift again.....

    Makes me think that the first organism would have been perfectly adapted to the environment they arose from. Without evolution it would have to be purely accidental I suppose. I can't see trial and error leading to the exact specimen required. The odds must have been heavily against life forming, no?
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    Forum Radioactive Isotope Paleoichneum's Avatar
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    Why would they?
    If more of us valued food and cheer and song above hoarded gold, it would be a merrier world. -Thorin Oakenshield

    The needs of the many outweigh the need of the few - Spock of Vulcan & Sentinel Prime of Cybertron ---proof that "the needs" are in the eye of the beholder.
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  8. #7  
    Forum Radioactive Isotope zinjanthropos's Avatar
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    Quote Originally Posted by Paleoichneum View Post
    Why would they?
    I'm thinking that the first organism arrived already adapted to its environment. Since it was the first living organism then it hadn't evolved at that point. It's like Goldilocks, conditions just right for that particular organism. I'm figuring that whatever that condition was, happened to be a rarity. If I knew what the condition was and if it was commonplace then I'd retract that last statement. Granted, there may have been other first organisms created under different conditions that didn't get past the first day. I know people are working diligently to recreate not only the conditions but life itself. They don't seem to be having much luck, so perhaps these conditions are extremely rare.
    All that belongs to human understanding, in this deep ignorance and obscurity, is to be skeptical, or at least cautious; and not to admit of any hypothesis, whatsoever; much less, of any which is supported by no appearance of probability...Hume
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  9. #8  
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    Quote Originally Posted by zinjanthropos View Post
    Quote Originally Posted by Paleoichneum View Post
    Why would they?
    I'm thinking that the first organism arrived already adapted to its environment. Since it was the first living organism then it hadn't evolved at that point. It's like Goldilocks, conditions just right for that particular organism. I'm figuring that whatever that condition was, happened to be a rarity. If I knew what the condition was and if it was commonplace then I'd retract that last statement. Granted, there may have been other first organisms created under different conditions that didn't get past the first day. I know people are working diligently to recreate not only the conditions but life itself. They don't seem to be having much luck, so perhaps these conditions are extremely rare.
    Why "just right" though? As I pointed out, reproductive success is the determinant. So long as the proto-organism was able to reproduce faster than it was killed off by the environment, its lineage would survive. Nothing has to be optimised for that to occur. You may be right that the initial conditions were rare, but as we don't have a working hypothesis of the process we can't say even that with any confidence.

    As for your last statement, I rather doubt anybody anywhere is diligently working to recreate life itself. Do you have references for that? What I think they are doing is testing various hypotheses for the formation of some of the building blocks, which is a lot more modest and realistic as an objective.
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    Forum Radioactive Isotope zinjanthropos's Avatar
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    I was thinking about scientists like Martin Hanczyc and Craig Venter. To the best of my knowledge, no one has created life from scratch. One thought that keeps popping into my head is, if life formation is that prevalent and there's plenty of allowable sets of conditions then why have we not observed it here occurring on Earth time after time? Is the answer ...because the conditions are no longer right for it? I'd be more than happy to hear of another reason. Is there any possibility that life is still being created here on Earth somewhere?
    All that belongs to human understanding, in this deep ignorance and obscurity, is to be skeptical, or at least cautious; and not to admit of any hypothesis, whatsoever; much less, of any which is supported by no appearance of probability...Hume
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  11. #10  
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    Quote Originally Posted by zinjanthropos View Post
    I was thinking about scientists like Martin Hanczyc and Craig Venter. To the best of my knowledge, no one has created life from scratch. One thought that keeps popping into my head is, if life formation is that prevalent and there's plenty of allowable sets of conditions then why have we not observed it here occurring on Earth time after time? Is the answer ...because the conditions are no longer right for it? I'd be more than happy to hear of another reason. Is there any possibility that life is still being created here on Earth somewhere?
    Yes well neither of them has ambitions to recreate life. They work on bits of the puzzle, just as I was saying.

    Regarding why we haven't observed life arising, I suggest considering two things:

    First how long we have around and able to observe such a thing. About a hundred years, if that?

    And second, think of all the already existing organisms that would find any inorganic sources of biomolecules a useful source of nutrients.

    So I suppose it is just possible that life might be arising somewhere, but just about all the possible niches are already overrun with organisms.
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