Origin of Life and Consciousness - Physical View

  1. Pythagorean

    Pythagorean 4,582
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    Could one say that the origin of life came about when a set of particles arranged in the right way were tipped into a sort of energy equilibrium that jiggled things back and forth, in obedience to physical laws (modern physical laws of course)

    And as this interaction of physical laws become more complex (where we study the trends of their overall behavior: chemistry, biochemistry, biology, etc.) they eventually led to organisms that interact, not solely on a biochemical level but at a macro-level too, perceiving, processing, and interacting on a level of general summary of all the micro interactions (what we call consciousness).

    I'm curious, how did this transition, between being a little chemical interaction factory (a single cell and its organelles) to a large-scale physical interaction machine (a creature with organs) occur?
     
  2. jcsd
  3. jim mcnamara

    jim mcnamara 1,469
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    I can't answer paragraphs I & II.

    III: Mostly the development of eukaryotic organisms during the Pre-Cambrian in the presence of an oxygen atmosphere. Eurkaryotic cells arise out of several simpler cells "merging" into another cell; taking over specific jobs. The mitochondrion is the best example. It has it's own DNA. It handles cell respiration - it fuels the rest of the cell. Mitochondrial activity requires higher levels of atmospheric/ambient oxygen. Chloroplasts are another good example.

    Basically it required that the atmosphere became oxidizing, and cells became able to thrive in oxygen. Early protobacteria (archeabacteria) largely exist today only in anerobic environments or in very extreme envrionments like hot springs.

    Microbiologists have known for 50 years that unrelated species of procaryotic bacteria can exchange DNA. And there are examples of multispecies globs of these guys growing in environments where one single species would fail. When I was current in this stuff, there was a big hunt on to see if a sort of 'halfway' organelle/symbiont could be found in procaryotes. Several were identified.
     
  4. Pythagorean

    Pythagorean 4,582
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    thank you for your reply, jim.

    I understand why you wouldn't want to answer I & II.

    I've heard a bit about mitochondria when discussing this before. When you speak of cells "merging" together, the description I generally hear is that mitochondria was thought to once be a sort of virus, but ended up forming a symbiotic relationship with many of the cells it "invaded". The two cells now "merged" took on different properties than either cell alone, because the mitochondria was able to produce energy must faster.

    what is "it"? The actual merging of the some primitive cell and mitochondria? Or the transition from small micro-interaction to macro-interaction?
     
  5. I would say bacteria and not virus. I suppose it could be either way...either the mitochondria invaded a cell or the cell devoured the mitochondria. Whichever way though, the symbiotic nature of their respective biochemistry is advantagious to both. Mitochondria love the oxygen our cells provide and our cells love the ATP that mitochondria provide as a waste product.

    On a macro scale we also have bacteria that live within our digestive systems as well.
     
    Last edited: Aug 28, 2007
  6. Pythagorean

    Pythagorean 4,582
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    and by love you mean it stimulates activity in the respective cells?
     
  7. jim mcnamara

    jim mcnamara 1,469
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    What is "it" - it = chemical process (involving cyctochrome C) which is "toxified" by things like cyanide and some other molecules found in the early reducing atmosphere.
     
  8. Some theoretical models suggests that the first primitive replicating molecule arose by that kind of natural experiments, assembled by the laws of chemistry and split by radiation somewhere between the formation of the earth and the first known lifeforms. According to the models, natural selection most likely took hold afterwards, as the molecules that reproduced better made more copies of itself.
     
    Last edited: Aug 29, 2007
  9. Well, yes I reckon "love" is a very unscientific word. :)

    Mitochondria feed on oxygen as an energy source and cells use their waste product (ATP) as an energy source.

    Without mitochondia, I doubt the plant or animal kingdoms would have ever taken off. Although plants have a similar relationship with chloroplasts, so perhaps they could have still evolved without mitochondria.
     
  10. Pythagorean

    Pythagorean 4,582
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    In my studies on lightning, I've read that it has been speculated as a possible contributor to life.

    (lightning gives off gamma radiation)
     
  11. Astronuc

    Staff: Mentor

    Gamma radiation originates from the nucleus or subatomic particle decay/interaction (e.g. positron annihilation), and lightning does not affect the nuclei of atoms.

    Lightning is an electrical discharge, i.e. a large current of electrons, and that discharge produces optical and perhaps UV, and perhaps an exceedingly small amount of very low energy X-ray. The voltage is on the order 100 kV spread along km or so of atmosphere, so locally the V/m is not great.

    The temperature of the atmosphere around the lightning discharge is about 30,000 K ( http://hypertextbook.com/facts/1999/DavidFriedman.shtml ) and with an equivalence of 11,605 K/eV, that's no more than 3 eV, which is well below the ionization energy of H (13.6 eV) which is the lowest energy X-ray. More likely, the highest energy photons would be UV.

    This might be of interest - http://en.wikipedia.org/wiki/Ultraviolet

    With respect to "obedience to physical laws (modern physical laws of course)", Nature is what it is and always has been, and the laws of physics are what they regardless of our understanding or knowledge of them. Certainly somehow atoms combined to form simple molecules, which interacted to form more complicated molecules, which then interacted to form complex structures like DNA, mitochondria and cells.
     
    Last edited: Aug 30, 2007
  12. Pythagorean

    Pythagorean 4,582
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    Gamma radiation has been detected coming from lightning clouds. They actually seem to be associated with sprites a lot. This is a popular subject at our university, so there's a lot of Uman available in our libraries. Explanations are still theoretical for it.

    From Uman:
    He also includes the references to reports that detected gamma-ray bursts.

    from Lightning: Physics and Effects
     
  13. Pythagorean

    Pythagorean 4,582
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  14. Astronuc

    Staff: Mentor

    Hmmmm. I see that people are detecting "terrestrial gamma ray flashes", or TGFs.

    But in 1994, scientists using the Compton Gamma Ray Observatory satellite first detected gamma rays seemingly originating near the earth's surface. And researchers quickly found evidence that those emissions were connected to lightning, Cummer said.

    Beginning in 2002, the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) satellite -- launched to study x-rays and gamma rays from the sun --also began detecting larger numbers of what scientists began terming terrestrial gamma ray flashes (TGFs).

    From Sciencedaily article cited by Pythagorean.

    Terrestrial Gamma-Ray Flashes (TGF's) observed with BATSE
    http://www.batse.msfc.nasa.gov/batse/tgf/

    RHESSI Terrestrial Gamma-ray Flashes: Current Status
    http://sprg.ssl.berkeley.edu/atmos/tgf/dsmith_annot.pdf

    http://en.wikipedia.org/wiki/Terrestrial_gamma-ray_flash

    OK, based on the brehmsstrahlung, I agree that the energetic photons are gamma radiation, as opposed to X-ray. I stand corrected.

    Cool picture of a lightning discharge.
    http://www.lightning.ece.ufl.edu/

    Thank you, Pythagorean. :smile:
     
  15. Pythagorean

    Pythagorean 4,582
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    No problem. It's amazing how little we know about what goes on inside the lightning cloud. Uman has remarked that the lightning bolt we see strike the ground is just the "tip of the iceberg" of a lightning cloud.

    Excellent picture; is that uniformity on the left side a lightning rod connecting to the stepped leader on the right?
     
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