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About Evolution

  1. Aug 22, 2012 #1
    We know the exact age of Universe and the earth.
    We know when life began on earth.
    Is the formation of life a result of random grouping of atoms and molecules?
    Is evolution the outcome of random mutations?
    If so, is the chances of such series of random mutations resulting in formation of human beings, consistent with probability theories that it might be possible in some 4.5 billion years.
    My motto is "I doubt that although Human Evolution may be outcome of random events and hence a happening of chance, we could appreciate it for a rare outcome."
    But since I know almost nothing on this subject, feel free to teach me the basics.
     
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  3. Aug 22, 2012 #2

    Evo

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    Staff: Mentor

    First, you've confused evolution with abiogenesis.

    http://en.wikipedia.org/wiki/Abiogenesis

    Then read the FAQ on evolution.

    https://www.physicsforums.com/showthread.php?t=543950

    Please start making an effort to at least search for basic information on the internet and reading FAQs that we have gone to the trouble of posting.
     
    Last edited: Aug 22, 2012
  4. Aug 23, 2012 #3

    Pythagorean

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    We don't know the exact age of the universe and earth. We have a pretty decent idea about Earth. The Universe relies on the assumption that we can exactly reverse the current rate of the expansion of the universe to a tiny point and call that the beginning; I'm not sure how valid that assumption is, but you might ask the cosmology subforum what they think.

    The chances are near zero, of course, with no a priori knowledge. But the chances are exactly one with our posteriori knowledge.

    Whether we should appreciate it or not is not really a scientific question, but many scientists think we should. One of my favorite examples is Carl Sagan who always raved about us being made of the rarest material in the universe and that we are made from star stuff.

    As for abiogenesis, there is a wonderful video that's been posted here before that explains how easy it would be fore life to come about in early Earth conditions.

    If you want to get right to the technical details, go to ~2:42 or click here:
    http://www.youtube.com/watch?v=U6QYDdgP9eg&feature=player_detailpage#t=172s

    for the whole viewing (which includes dispelling creation myths) enjoy the full video here:
     
    Last edited by a moderator: Sep 25, 2014
  5. Aug 23, 2012 #4

    Ryan_m_b

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    Within a few hundred million years we have an idea but that's not "exact". Also the formation of Earth and life were not single events but long processes.
    See the good answers others have given above
    No mutations are a small part of evolution. Whilst mutations are random they have non-random effects determined by the environment.
    It's not so much a question of probability as a journey accross a fitness landscape.
    Human beings could not have arisen at any other time. We are the product of our lineage and could no more have arisen at another time than you could have been born to your ancestors.

    For the basics read and watch the resources linked above, our evolution intro also has links at the bottom to further resources.
     
  6. Aug 23, 2012 #5
    Stuart Kauffman in "At Home in the Universe" proposes that life is a result of "autocatalytic sets" in which the molecules in the set speed up the very reactions by which they themselves are created: A makes B, B makes C, C makes A again. He suggests it is these autocatalytic sets which are at the heart of life. The book is non-technical (basically) and you might find it interesting.
     
  7. Aug 29, 2012 #6
    Mutation is, according to our best understanding, entirely random. Other ways in which genetic diversity arise such as methylation, gene transfer, and sexual shuffling, are also largely random.

    The observed directionality of biological evolution is attributable to natural selection.
    Whereby those variations that produce optimal phenotypes for reproductive success in the prevailing environment are favored.

    It must be remembered that environments themselves are also in a state of dynamic flux. This provides an explanation for the phenomenon of "punctuated" evolution. Sometimes biological evolution has to wait for the environment to "catch up", if you will excuse the metaphor.
    For example, the emergence of large multicellular organisms was unable to occur until after atmospheric oxygen levels became sufficiently high.

    Turning to the quite separate issue of abiogenesis, one of the most intractable of the many problems with trying to derive a mechanism is that of the development of the cell.
    While lipid vesicles can quite easily be generated in the lab (and I have used the fatty coacervate jacket model in some of my own early writings) they do not meet the requirement for two way selective interaction with the surrounding medium that is required for a cell to survive, let alone the quintessential proton pump.
    The most plausible proposition I have come across so far is the alkaline thermal vent model.
    This is discussed in the very fine book "Life Ascending" by Nick Lane which is available in most public libraries.
     
    Last edited: Aug 29, 2012
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