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Thread: Origin of Life

  1. #1 Origin of Life 
    Moderator Moderator AlexP's Avatar
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    I would like to start an official Origin of Life thread to see what people's thoughts are on the topic. I want to declare that this is totally open, and anything goes, including whatever definition you personally give for life, since that plays a big part in this. Genetics first, metabolism first, proteins first, self-replicating molecules, whatever. Open discussion.


    "There is a kind of lazy pleasure in useless and out-of-the-way erudition." -Jorge Luis Borges
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  3. #2  
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    I always like the theory that selfreplicating genetic material came from self replicating inorganic material such as crystals. Crystals are capable of propagating and increasing their own size by vurtue of their bonds. If one crystal eventually led to a more complicated crystal being formed which was better at replicating and so on gradually forming a more "organic" compound and eventually DNA. There after I suppose is where the leap is, how do viruses/ mitochondria /bacteria or whatever was first then form!


    Another theory (which doesnt really answer the question regarding the origin of life iteslf) which I find interesting is the theory that we in fact originated on a comet/meteor or from space. In space surrounding the planet there is a higher level of organic material (by concentration) than there is on earth. Much of which is suspected to be due to nearby comets giving off debris which is then slowly attracted towards the earth by gravity. What adds weight to this theory is the fact that earth is so thinly "dusted" with organic material when compared to the rest of the planet. Each day, tons of debris falls on our planet; much of it being organic. It is not totally inconceivable that a microorganism or some other prerequisit of life may have landed with it and the temperature and surrounding material and water allowed it to propagate.
    But that just raises the question where did IT come from!


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  4. #3  
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    Quote Originally Posted by Robbie
    In space surrounding the planet there is a higher level of organic material (by concentration) than there is on earth.
    ' didn't know that...interesting fact.
    Whence comes this logic: no evidence = false?

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

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  5. #4  
    Universal Mind John Galt's Avatar
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    Any consideration of the origin of life needs to consider these three aspects:

    a)Source for pre-biotic molecules
    b)Emergence of metabolic cycles
    c)Development of a genetic code and replication system

    Although they are intimately linked they are also, likely,somewhat independent.

    The source of pre-biotic molecules is fortunately easy to explain. Interstellar space is replete with a wide variety of organic molecules. Over one hundred have been identified in GMCs (Giant Molecular Clouds), or in the tails of comets, or in meteorites, especially carbonaceous chondrites. It is probable that the material from which we are constructed came, along with the water of our oceans, from cometary impact during the Heavy Bombardment Period.

    The other two aspects are more difficult to explain with confidence.
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  6. #5  
    Forum Freshman César's Avatar
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    In space surrounding the planet there is a higher level of organic material (by concentration) than there is on earth. Much of which is suspected to be due to nearby comets giving off debris which is then slowly attracted towards the earth by gravity. What adds weight to this theory is the fact that earth is so thinly "dusted" with organic material when compared to the rest of the planet.
    This is original, to say the least. Would you mind giving me a source so that I can learn more about this theory?

    In any case, let's assume it is true. This would imply that there is life throughout all the Universe. Another interesting point is: how did the organic material arrived to the comets?

    Best regards,

    César
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  7. #6  
    Universal Mind John Galt's Avatar
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    Quote Originally Posted by César
    In space surrounding the planet there is a higher level of organic material (by concentration) than there is on earth. Much of which is suspected to be due to nearby comets giving off debris which is then slowly attracted towards the earth by gravity. What adds weight to this theory is the fact that earth is so thinly "dusted" with organic material when compared to the rest of the planet.
    This is original, to say the least. Would you mind giving me a source so that I can learn more about this theory?
    In any case, let's assume it is true. This would imply that there is life throughout all the Universe. Another interesting point is: how did the organic material arrived to the comets?
    "Buenos dias, Cesar. Let me clear up one possible misunderstanding. Organic material means carbon compounds. These need not be of biological origin.

    What is the source of interstellar organic material?
    Carbon is the sixth most abundant element in the Universe, after hydrogen, helium, oxygen, neon and nirtogen. Expelled from stars in supernovae explosions and by other stellar mechanisms it is abundant in interstellar space. As carbon is also a reactive element it readily forms compounds. More than one hundred and twenty five carbon compounds have been identified in interstellar and circumstellar regions.
    http://books.nap.edu/openbook.php?re...=11860&page=23

    How does it get into comets?
    Comets condense in the outer reaches of planetary systems as those systems form from the collapse of part of an interstellar cloud. The organic molecules that have formed within that cloud are incorporated in the comet. Additionally, the comet picks up a coating of organic molecules as it moves through space. There is a wealth of material on the web discussing such observations. Here is a single example.
    http://www.planetary.org/explore/top...s/tempel1.html

    I know that doesn't quite address your question, but then I'm not entirely sure what Robbie was trying to say.
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  8. #7  
    Forum Freshman César's Avatar
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    Thank you so much Ophiolite for your kindness. I'm fully aware of what you explain (as a matter of fact the last entry in my blog discusses the finding of PN in VY Canis Majoris, and the importance of finding phosphorus based compounds in the interstellar space). I only wanted Robbie to make a coherent discourse because, as yourself, I'm not entirely sure what Robbie was trying to say.

    Best regards,

    César
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  9. #8  
    Universal Mind John Galt's Avatar
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    Quote Originally Posted by César
    (as a matter of fact the last entry in my blog discusses the finding of PN in VY Canis Majoris, and the importance of finding phosphorus based compounds in the interstellar space).
    I just took a look at that. My spanish is pretty rudimentary (I lived in Mexico for nine months and we both know the Mexicans don't speak Spanish. ), but I was able to follow most of it. Nice blog.
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  10. #9  
    Forum Freshman César's Avatar
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    You are very kind, thank you.

    Best,

    C
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  11. #10  
    Moderator Moderator AlexP's Avatar
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    RNA World hypothesis: same 4 bases we have today? And so you have some RNA floating around, what's the next step toward life as we know it?
    "There is a kind of lazy pleasure in useless and out-of-the-way erudition." -Jorge Luis Borges
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