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Thread: What came first, the Prokaryote or Eukaryote?

  1. #1 What came first, the Prokaryote or Eukaryote? 
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    I remember being taught that all life in some distant time ago (around 10 million years ago) life appeared spontaneously in the sea in the form of single celled life. But i have heard arguements since then that may suggest that life actually came in the form of a Eukaryote.

    Does anyone know if there is any defined proof?


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    First, your time scale is a little off. Ten million years ago is yesterday in geological terms. Life is thought to have begun around 3.8 to 4.0 billion years ago.

    There is little doubt that prokaryotes were the first life forms. The current consensus opinion is that eukaryotes emerged through symbiotic relations established between various prokaryotes.

    This is an idea that was originally proposed by Lynn Margulis and despite early resitance has now largely been accepted. On this basis mitochondria and chloroplasts, elements of eukaryotes, were orginally independent organisms.

    I vaguely recall Fred Hoyle trying to make a case for eukaryotes coming first, as part of his argument for panspermia, but it was a weak case.


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    Quote Originally Posted by John Galt
    First, your time scale is a little off. Ten million years ago is yesterday in geological terms. Life is thought to have begun around 3.8 to 4.0 billion years ago.

    There is little doubt that prokaryotes were the first life forms. The current consensus opinion is that eukaryotes emerged through symbiotic relations established between various prokaryotes.

    This is an idea that was originally proposed by Lynn Margulis and despite early resitance has now largely been accepted. On this basis mitochondria and chloroplasts, elements of eukaryotes, were orginally independent organisms.

    I vaguely recall Fred Hoyle trying to make a case for eukaryotes coming first, as part of his argument for panspermia, but it was a weak case.
    Oh, how inetersting. Fred Hoyle is one of my Hero's of physics and astrophysics. I never knew he tried to make such a case, though i was aware of his investigation into Panspermia Theory, and fuelled his personal attention to some Creator.
    Only the mind can think twice simultaneously about a subject, but only one thing can inexorably come out of it. A choice.
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    Quote Originally Posted by Manynames
    Quote Originally Posted by John Galt
    First, your time scale is a little off. Ten million years ago is yesterday in geological terms. Life is thought to have begun around 3.8 to 4.0 billion years ago.

    There is little doubt that prokaryotes were the first life forms. The current consensus opinion is that eukaryotes emerged through symbiotic relations established between various prokaryotes.

    This is an idea that was originally proposed by Lynn Margulis and despite early resitance has now largely been accepted. On this basis mitochondria and chloroplasts, elements of eukaryotes, were orginally independent organisms.

    I vaguely recall Fred Hoyle trying to make a case for eukaryotes coming first, as part of his argument for panspermia, but it was a weak case.
    Oh, how inetersting. Fred Hoyle is one of my Hero's of physics and astrophysics. I never knew he tried to make such a case, though i was aware of his investigation into Panspermia Theory, and fuelled his personal attention to some Creator.
    Upon reading some of your posts, I think you need a little help to grasp the basics of evolutionary theory. I suggest using these books as primers:

    Mitochondria and the Meaning of Life- Nick Lane

    Fish with Fingers, Whales with Legs- Carl Zimmer

    Then, to keep up with current trends:

    Your Inner Fish- Neil Shubin

    and

    Endless Forms Most Beautiful: The New Science of Evo Devo by Sean Carroll
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    if you look at the theory of endosymbiosis it pretty much explains why the prokaryote had to have come first. the theory basically states that eurkaryotes evolved from simple prokaryotes engulfing other prokaryotes. a good example of this is mitochondria. mitochondria is about the size of a prokaryotic cell and has its own DNA and ribosomes which suggest that it was, at one time, its own cell. if you look at this theory it seems pretty obvious that the prokaryote would have had to come first.
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    Not to mention that the case for abiogenesis decreases to virtually non-existent if eukaryotes were first.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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    There's also the fact that eukaryotes share homology with both Archaea and Bacteria, too separate groups of prokaryotes. Further evidence that eukaryotes came from the symbiotic association of two prokaryotic organism.

    Although, I always like to point out that besides the mitochondria and chloroplast aspect of the endosymbiotic theory, Lynn Margulis' ideas are predominantly absurd.
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    Quote Originally Posted by i_feel_tiredsleepy
    Lynn Margulis' ideas are predominantly absurd.
    Do you want to expand on that, perhaps in separate thread?
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    Quote Originally Posted by John Galt
    Quote Originally Posted by i_feel_tiredsleepy
    Lynn Margulis' ideas are predominantly absurd.
    Do you want to expand on that, perhaps in separate thread?
    I don't really want to make a "bash Lynn Margulis" thread. She was right on the money with mitochondria and chloroplast. However, she still supports that all organelles are of endosymbiotic origin, which is a bit ridiculous.

    Edit: She also thinks that symbiosis is the driving force of all evolution and that evolution is driven by gene exchange between viruses, bacteria, and eukaryotes. These are very much fringe ideas.
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    You can't say Margulis was "right" about endosymbiosis. It remains a theory and a well accepted one but is not proven any more than evolution or any biological theory.

    I also take issue that "case for abiogenesis decreases to virtually non-existent if eukaryotes were first" As we've no idea of the naure of biogenesis and there's no well accepted theory as to initiation of life, it's not possible understand what came 1st. That may come from the fossil record.
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    Quote Originally Posted by Jorge1907
    You can't say Margulis was "right" about endosymbiosis. It remains a theory and a well accepted one but is not proven any more than evolution or any biological theory.

    I also take issue that "case for abiogenesis decreases to virtually non-existent if eukaryotes were first" As we've no idea of the naure of biogenesis and there's no well accepted theory as to initiation of life, it's not possible understand what came 1st. That may come from the fossil record.
    That should be abiogenesis, i.e. life from non-life. Eukaryotes are more complex and organised generally than prokaryotes, as well as bigger. Fossil evidence and genetic investigations place prokaryotes as having evolved before eukaryotes as well. In this case at least I would venture that simplicity is actually direct evidence of them being older. Abiogenesis necessarily had to start with simpler forms of life.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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    Isn't horizontal gene trasfer a new emerging "scene" in evolutionary genomics; shaking up the traditional evolutionary tree? Then there's the guys pushing at the edges of current evolutionary theory, wherein natural selection is relegated to a status that may not be all that important in the grand scheme of things and where all manner of non-adaptive processes are far more important. Then too there's attempts to look at evolution occurring at a level above the species level - ecosystem evolution, for example.


    Maybe Lynn isn't too far off the mark (although her rhetoric is a bit strong and over the top)
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    Quote Originally Posted by gottspieler
    Quote Originally Posted by Manynames
    Quote Originally Posted by John Galt
    First, your time scale is a little off. Ten million years ago is yesterday in geological terms. Life is thought to have begun around 3.8 to 4.0 billion years ago.

    There is little doubt that prokaryotes were the first life forms. The current consensus opinion is that eukaryotes emerged through symbiotic relations established between various prokaryotes.

    This is an idea that was originally proposed by Lynn Margulis and despite early resitance has now largely been accepted. On this basis mitochondria and chloroplasts, elements of eukaryotes, were orginally independent organisms.

    I vaguely recall Fred Hoyle trying to make a case for eukaryotes coming first, as part of his argument for panspermia, but it was a weak case.
    Oh, how inetersting. Fred Hoyle is one of my Hero's of physics and astrophysics. I never knew he tried to make such a case, though i was aware of his investigation into Panspermia Theory, and fuelled his personal attention to some Creator.
    Upon reading some of your posts, I think you need a little help to grasp the basics of evolutionary theory. I suggest using these books as primers:

    Mitochondria and the Meaning of Life- Nick Lane

    Fish with Fingers, Whales with Legs- Carl Zimmer

    Then, to keep up with current trends:

    Your Inner Fish- Neil Shubin

    and

    Endless Forms Most Beautiful: The New Science of Evo Devo by Sean Carroll
    I am not a niologist at heart, but it does hold significance i suppose in my area's of research.
    Only the mind can think twice simultaneously about a subject, but only one thing can inexorably come out of it. A choice.
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    Quote Originally Posted by Zwirko
    Isn't horizontal gene trasfer a new emerging "scene" in evolutionary genomics; shaking up the traditional evolutionary tree? Then there's the guys pushing at the edges of current evolutionary theory, wherein natural selection is relegated to a status that may not be all that important in the grand scheme of things and where all manner of non-adaptive processes are far more important. Then too there's attempts to look at evolution occurring at a level above the species level - ecosystem evolution, for example.


    Maybe Lynn isn't too far off the mark (although her rhetoric is a bit strong and over the top)
    Thank you Zwirko. You said what I wanted to say, but more concisely and elegantly. I'm preparing some comments for a thread on evolution 'directed' by cooperation as much as by competition and these thoughts fit right in.

    Quote Originally Posted by manynames
    I am not a niologist at heart,
    Biologist?
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    Quote Originally Posted by John Galt
    Quote Originally Posted by Zwirko
    Isn't horizontal gene trasfer a new emerging "scene" in evolutionary genomics; shaking up the traditional evolutionary tree? Then there's the guys pushing at the edges of current evolutionary theory, wherein natural selection is relegated to a status that may not be all that important in the grand scheme of things and where all manner of non-adaptive processes are far more important. Then too there's attempts to look at evolution occurring at a level above the species level - ecosystem evolution, for example.


    Maybe Lynn isn't too far off the mark (although her rhetoric is a bit strong and over the top)
    Thank you Zwirko. You said what I wanted to say, but more concisely and elegantly. I'm preparing some comments for a thread on evolution 'directed' by cooperation as much as by competition and these thoughts fit right in.

    Quote Originally Posted by manynames
    I am not a niologist at heart,
    Biologist?
    :P Typo :wink: lol
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    Oh, thought you were a Nihilist biologist at heart.
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    Quote Originally Posted by spuriousmonkey
    Oh, thought you were a Nihilist biologist at heart.
    lol -- that is possibly true... lol
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    Quote Originally Posted by Zwirko
    Isn't horizontal gene trasfer a new emerging "scene" in evolutionary genomics; shaking up the traditional evolutionary tree? Then there's the guys pushing at the edges of current evolutionary theory, wherein natural selection is relegated to a status that may not be all that important in the grand scheme of things and where all manner of non-adaptive processes are far more important. Then too there's attempts to look at evolution occurring at a level above the species level - ecosystem evolution, for example.


    Maybe Lynn isn't too far off the mark (although her rhetoric is a bit strong and over the top)
    Lynn is pretty far off the mark, I grant horizontal gene transfer has a huge effect on prokaryotes and to a minor extent single celled eukaryotes. However, this doesn't negate natural selection. Whether an organism acquires the new gene from mutation or gene transfer is independent from the forces that determine the predominance of that gene in the population.

    I think Lynn would have a difficult time defending symbiosis as a driving force of evolution in plants and animals since the germ cells aren't commonly accessible to bacterial and viral genomes.
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