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What is needed for life?

  1. Feb 20, 2015 #1
    Our definition of life keeps changing as we discover living things in places we did not think life could exist. My question is how would we define life if this trend continues? As of now we believe all living things need liquid water. But we may find organism living in any kind of liquid. But is a liquid even necessary? Is solid material needed for life to anchor on? I am thinking of life in the most optimistic way and wondering how to define it. Could in theory life take hold anywhere there is a slow exchange of energy over a long period of time?
     
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  3. Feb 20, 2015 #2

    Ryan_m_b

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    Our definition of life doesn't really change when we find organisms living in places we didn't think they could, on the contrary we recognise them because of our definitions. As we understand it water is necessary for life but there has been speculative work on using other liquids as a solvent. I doubt any non liquid media could give rise to life.

    There is no strict definition of life and there is constant debate regarding things like viruses and if they should count as alive. The broad consensus is listed here:
    http://en.wikipedia.org/wiki/Life#Definitions
     
  4. Feb 20, 2015 #3
    So a liquid environment which has a lot of activity (but not to much) and a good variety of elements and giving enough time may be all that is needed?
     
  5. Feb 20, 2015 #4

    Ryan_m_b

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  6. Feb 20, 2015 #5
    Thanks for the link :) It seems life has a lot of limitations chemically. But putting the chemical soup aside for a second what else is a necessity? Life needs energy and it gets this energy from low entropy systems and contributes to the over all increase of entropy. So is the right chemical soup, a low entropy environment, and time may be all that is needed?
     
  7. Feb 20, 2015 #6

    Ryan_m_b

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    You'd need the right energy input at the right time with the right composition of elements, but we don't know for sure. Experiments like the Miller-Urey experiment showed that you could get certain biomolecules to form under "primordial" conditions. However there are theories that geology matters as well, IIRC there is speculation that pores in rocks aided in the formation of the first cellular structures.
     
  8. Feb 20, 2015 #7

    Pythagorean

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  9. Feb 20, 2015 #8
    Thank you. That article seems to be exactly what I am looking for.
     
  10. Feb 20, 2015 #9

    Pythagorean

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    No problem. Keep in mind that while many people appreciate England's approach, it's still speculative. But imo, it's worth testing experimentally.
     
  11. Feb 20, 2015 #10
    If his approach is not right I bet it is pretty close. Much how we use to think we were at the center of the universe, we also think life is something special. But we will eventually find out that it is just a natural process of entropy. Kinda of depressing.
     
  12. Feb 20, 2015 #11
    How would this be tested. I did not find anything about that?
     
  13. Feb 20, 2015 #12

    Pythagorean

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  14. Feb 20, 2015 #13

    Bystander

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    "... that would suggest this is the correct organizing principle.” Perhaps this would be better read as "...that would suggest this is the correct an organizing principle.”
     
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