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Heredity, containment, metabolism.

  1. May 11, 2005 #1

    saltydog

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    Not sure you guys have seen or talked about this already, but I just got on-line access to New Scientist Magazine. The Feb 12 2005 issue was about creating artificial life. Here's a short summary about a Los Alamos team's attempt to do so:

    The key difference between life and non-life is Darwinian evolution. This requires some sort of device, a molecule for example, to carry hereditary information. The device must have a separate identity from it's environment, that is, must be contained in some sort of container, and finally, must have an energy source: a metabolism. Thus we have the most fundamental definition of life: heredity, containment, metabolism. The Los Alamos group is attempting to simulate these three as follows:

    Containment: In a word fatty-acids. You know, polar on one end, non-polar on the other. Just like real cell membranes. These form "vesicles" naturally.

    Heredity: They're using PNA (peptide nucleic acids). Instead of ribose-phosphate backbone like DNA, these have protein chains to which nucleic acids are attached.

    Metabolism: I quote: "The Bug will also be supplied with inactive PNA precursors bound to a photosensitive molecule. . . . when light strikes this photosensitiser, it breaks off to release the active PNA fragment."
    Don't quite understand how that supplies energy at least along the lines of glycolysis, Kreb cycle, ATP synthesis, etc.

    Anyway, if you're interested in prebiotic evolution, you may wish to check out this issue.
     
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  3. May 11, 2005 #2

    selfAdjoint

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    They probably won't have Krebs-style metabolisms, but necessarily they will have some mechanism for extracting free energy from the environment and deploying it usefully within the containment vesicle. That would qualify as a metabolism in the general meaning of the word.

    What I like about this program is that if it succeeds the creationists will have no chance to object that they used "life to create life", since the whole chemical basis is different from existing life.
     
  4. May 11, 2005 #3
    It doesn't matter how strong the scientific proof against creationist arguments is. Some do not bother.
     
  5. May 11, 2005 #4

    saltydog

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    Ok, I can begin to understand the metabolism: it's photosynthetic. The action of light disassociates the photosensitiser. The resulting species (free-radiacals perhaps) are unstable and thus energetic and are availabe I guess to slough-off their free energy to drive other reactions.
     
  6. May 11, 2005 #5

    selfAdjoint

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    Sure, but the more you can back them into their little box and capture the high ground of public opinion, the better. The fact that evolution for all its scientific success has not been able to do that is the reason for these perpetually recurring school issues like Kansas.
     
  7. May 11, 2005 #6

    saltydog

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    Well, I'd have to say it's not a failing on the part of Evolution but rather a fine reflection of the frailties of human intellect.
     
  8. May 12, 2005 #7
    Today I read they constructed reproducing little robots(nanobots?).
     
  9. May 12, 2005 #8

    selfAdjoint

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    The problem is there isn't any sufficiently powerful "smoking gun' to demonstrate to the public that evolution is real. "Lucy" was the closest to what I have in mind. Creation of new life in the lab would be another. Yes that isn't technically evolution, but the public always confuses evolution with the origin of life.
     
  10. May 12, 2005 #9

    saltydog

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    Perhaps none they are willing to learn about. I think there's tons really but even if I gave some examples, (the moth story is one of my favorites), they wouldn't believe it. I'm not the best person to defend evolution as I've been out of it of late; other people perhaps here could offer some fine examples, perhaps the best we can come up with of "microevolution" by natural selection. I'm confident the list would be astounding.
     
  11. May 12, 2005 #10

    selfAdjoint

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    Critics managed to smudge up the peppered moth story, so the creationist debaters can represent it as a wash, if not a phony imposture. And to reply "Wait, the critics were routed!" only elicits a scornful "Routed by whom?" and the implication that once again the evolutionists have fearfully circled the wagons. You can't debate them; you must crush them in the news. Headlines that can't be debated away.
     
  12. May 12, 2005 #11

    saltydog

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    Alright, peppered moth. Should have taken the time to google it to get my story straight. It is a beautiful example nevertheless. There are thousands more as anyone involved in Evolutionary Biology would tell us. I am always amazed when I learn of a new one (adaptation through natural selection that is). Really I think no headlines of any metric, with due respect sir, would ever convince the creationist of their erroneous ways. We have so much more evolving to do.
     
  13. May 13, 2005 #12
    Problem is this.

    Its easy to reject evolution because there are no mutations that 'add a new function'. Evolution doesn't do that with one mutation so its impossible to show it.

    Then its easy to not understand the effect of evolution over millions of years. The human brain isn't programmed for time scales like that. And if they do manage it a little, they can always forget about natural selection and it all breaks down anyway.

    As long as a creationst can't watch an organism and see it evolve they have the possibilities not to believe it is possible.

    This is the 'smoking gun' most creationists ask for. They want to see a creature evolve into something totally different.
     
  14. May 13, 2005 #13

    saltydog

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    I agree I find it impossible to comprehend millions of years just like I find it incomprehensible to fathom the size of the galaxy. Why then am I so confident of evolution to the extent I shall take it and it's many implications (religous and otherwise) with me to my grave without the slightest reservation? I think history has a lot to do with it, particularly that of Medicine and Astronomy.

    I have a picture . . . a nice one, middle-ages . . .wait, let me get it . . . drilling right through his head they are. And what's that funnel on his head anyway? Bacterial contamination? What bacteria? Removing the stone of folly? Poor chap. Antibiotics? Sure they had them back then. One was called "keep-your-mouth-shut-cillin". Another one was "stay-away-from-the man-with-the-funnel-on-his-head-cillin". Best you walk a straight line back then I suppose. Astronomy? Oh God, I best not get started as this is a Biology forum.

    Our fragile understanding of the world changes along with our fragile selves. Carl Sagan was right: what a demon-haunted world so many still live in. It's just not there though, not any of it. What did Author C. Clark say, "a technology sufficiently advanced is indistinguishable from magic". I'd suppose evolution is a bit like that wouldn't you say? Supremely intricate, interconnected, and complex. Highly advanced indeed! Magic to some, less so to others.
     
    Last edited: May 13, 2005
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