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Thread: Origin of Life

  1. #1 Origin of Life 
    Moderator Moderator AlexP's Avatar
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    What is the most commonly accepted theory of how life began? RNA World, Iron-Sulfur World, Clay theory, Autocatalysis, etc. Or if there isn't really a most accepted one, what do all of you think is most likely?


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    WYSIWYG Moderator marnixR's Avatar
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    i'm not aware that there's any leading contender - it could be any of the ones you mentioned or a combination of them

    my bet is on somewhere very hot + shielded from UV light
    best places would be vents or inside the crust


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  4. #3  
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    I believe this will become the most accepted view in time:

    Stuart Kauffman's "autocatalytic" set: When a chemical system grows sufficiently complex, products begin to emerge which catalyze their own creation: A and B react to form C, C and D react to form E and E catalyzes the reaction which forms C. Given a supply of reagents (and energy supply), this system will sustain itself. When non-linear dynamics are added to the mix, given that our world is massively non-linear, self-organization becomes inevitable.

    All makes perfect sense to me. If you're interested in this line of approach, may I suggest the following:

    "At Home in the Universe" by Stuart Kauffman

    "Self-Organization in Biological Systems" by Camazine and others

    "Complexification" by John Casti

    "Signs of Life" by Richard Sole'
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  5. #4  
    M
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    So what makes chemical systems grow "sufficiently complex" and finally create re-producing living organisms? Random processes? Or is life-less chemistry subject to some sort of evolution in a certain direction (simplicity to complexity)? In mumbo-jumbo theory it might play out like this: a) life is the most complex thing we know, b) some chemistry can also be pretty complex, c) living organisms depend on a plethora of complex chemical processes, so d) chemical complexity leads to life. Throw in some non-linearity and it all sounds really cool! 8)

    Do we really know anything?
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    Forum Sophomore Nanobrain's Avatar
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    I do not quite understand the subject, due to my lack of touching of it. But, some use the explanation of information theory. Something about information loops(positive and negative feedback loops) causing the growth and complexity. I believe it is a bit of randomness, eventually turned to informational loops, growthed by more randomness reacting with the loops. Ugh, it's hard to explain when I don't fully understand. Maybe someone else can touch base here.
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    Quote Originally Posted by Nanobrain
    I do not quite understand the subject, due to my lack of touching of it. But, some use the explanation of information theory. Something about information loops(positive and negative feedback loops) causing the growth and complexity. I believe it is a bit of randomness, eventually turned to informational loops, growthed by more randomness reacting with the loops. Ugh, it's hard to explain when I don't fully understand. Maybe someone else can touch base here.


    Nanobrain; your broad theory may be more or less on the mark. Part two is the physics (chemistry, energy, etc,) that kick starts such information (chemical) loops.
    The origin of life isn't all that pursued in academic circles. It's a bit of a niche field that is dabbled in now and again. One issue is that the formation of life one day in a lab doesn't mean that life originated that way in Nature. Particular variables came together but there might be variations on the recipe....a bit like does it matter if you add salt to the water before you put in the potatoes or can you add the salt later and come out with the same results?
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    There is not a single issue. Asking 'How did life begin?' is akin to asking 'How did a primitive prokaryote morph into homo sapiens?' There is more than one step involved.

    We need to consider at least the following, as separate events/processes:

    The origin of metabolism
    The origin of the genetic code
    The origin of cells
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    WYSIWYG Moderator marnixR's Avatar
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    on the other hand, you could define the origin of life as the origin of replication of inherited characteristics with modification
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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  10. #9  
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    The origin of life is God. :wink: (Just being humorous here; don't start attacking me).
    Whence comes this logic: no evidence = false?

    http://www.atheistthinktank.net/thinktank/index.php

    Theists welcome.
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  11. #10  
    WYSIWYG Moderator marnixR's Avatar
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    what's GOD stand for ? Genetic Origin of Diversity ?
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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  12. #11  
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    Quote Originally Posted by marnixR
    on the other hand, you could define the origin of life as the origin of replication of inherited characteristics with modification
    You could define it any way you wanted - and yours is better than most. It wouldn't alter the fact that it was a multi step process. Your definition might cover the very last stage in that process - or not - but it would not be the whole story.
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    Quote Originally Posted by M
    So what makes chemical systems grow "sufficiently complex" and finally create re-producing living organisms?
    Here's what I believe:

    The evolving dynamics in space gives rise to the "apparent" increase in complexity we perceive. But we only scratch the surface in attempting to model and understand these dynamics and so I can't explain it well. Even modeling the growth of a termite mound involves coupled non-linear PDEs and the model even then is imprecise. The dynamics of life in general is extremely complicated but I can begin to see what may be driving increasing complexity: For example, if you sat at a particular point in the state space of the Lorenz Attractor, and allowed the underlying dynamics to evolve under some initial condition and map the subsequent trajectory, you'd see a fractal structure beginning to emerge all around you, (the butterfly picture, one of the three icons of Chaos Theory). As the dynamics evolves in time, and the trajectory is mapped in space, viewed from your perspective, the complexity appears to be increasing. The evolving dynamics is giving rise to this apparent complexity. But that is just a simple coupled set of 3 non-linear ODEs and nothing like real life. We just don't yet understand the dynamics of life.

    With regards to what causes change in form, I yield to Rene' Thom who said, "All destruction of forms, or morphogenesis, can be described by the disappearance of the attractor representing the initial forms, and the replacement by capture by the attractors representing the final forms". He means by catastrophe. You know, "the straw that breaks the camel's back". Catastrophe is all around us. We see it everywhere: processes flow smoothly up to a point which if breached causes the dynamics to change abruptly and often qualitatively: water changing to ice, avalanches, snapping bridges, punctuated equilibrium, Cambrian explosion, the divergence of man from ape, all of these driven (my opinion) by the inherent critical points (catastrophe points) contained in the underlying dynamics.
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    Re the definition. Life can be sliced and diced and defined within arbitrary parameters. Life is a manifestation of matter and energy that is subject to the physical properties of the universe in no way different than what we call non-life. A carbon atom is a carbon atom and variations 'have to' act in a certain way when other matter and energy impact it. I agree with Carl Sagan who viewed life as as 'nothing special' except to whatever overlay an intelligence puts on it. The chemistry involved is arbitrarily singled from other chemistry by an attempt to make sense of the world around us.

    There is no 'point in time' when an atom or molecule didn't act as it would otherwise. no point at which there was something to distinguish the chemistry of life from non-life. Matter and energy impact the same as they did before any arbitrary origin of life.
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  15. #14  
    Moderator Moderator AlexP's Avatar
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    Would it be better if i reworded to "the original simplest precursor to life," or does that not really cover it either?
    "There is a kind of lazy pleasure in useless and out-of-the-way erudition." -Jorge Luis Borges
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  16. #15  
    Universal Mind John Galt's Avatar
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    Quote Originally Posted by Chemboy
    Would it be better if i reworded to "the original simplest precursor to life," or does that not really cover it either?
    I think you may be needlessly getting hung up on definitions. Rather get immersed in the intricacies and complexities of the processes that may have been involved in the origin(s) of whatever.

    Contrary to Jellyologist life, as an emergent property of zetaman's chaos and complexity, is distinct from non-life. It just doesn't make much sense to try to pinppoint when/where the distinction occurs.
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  17. #16  
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    Quote Originally Posted by Ophiolite
    Quote Originally Posted by Chemboy
    Would it be better if i reworded to "the original simplest precursor to life," or does that not really cover it either?
    I think you may be needlessly getting hung up on definitions. Rather get immersed in the intricacies and complexities of the processes that may have been involved in the origin(s) of whatever.

    Contrary to Jellyologist life, as an emergent property of zetaman's chaos and complexity, is distinct from non-life. It just doesn't make much sense to try to pinppoint when/where the distinction occurs.
    au contraire. It's all about definitions. The first line of Science 101. Define terms... or it's all apples and oranges.
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  18. #17  
    Moderator Moderator AlexP's Avatar
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    ok, so, in any case... Is the RNA World hypothesis plausible?
    "There is a kind of lazy pleasure in useless and out-of-the-way erudition." -Jorge Luis Borges
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  19. #18  
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    Quote Originally Posted by Jellyologist
    au contraire. It's all about definitions. The first line of Science 101. Define terms... or it's all apples and oranges.
    This is true for everything except life: that's what makes it unique.
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