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Are viruses life?

  1. Jun 6, 2009 #1
    Are viruses life?
     
  2. jcsd
  3. Jun 6, 2009 #2

    Ygggdrasil

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    It depends on how you define life (which surprisingly is not very well defined).
     
  4. Jun 6, 2009 #3

    DaveC426913

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    What are your thoughts on the matter?
     
  5. Jun 6, 2009 #4

    symbolipoint

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    Do they perform metabolism, even if using a hosts organisms cells to do so?
    Are virii irritable?
    Can they reproduce?

    If yes to all of those, then virus seems to be life.
     
  6. Jun 7, 2009 #5

    DaveC426913

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    As a discrete unit, no.

    As a discrete unit, no.

    Virii corrupt living cells. Arguably, it is the living cells that is doing the irritation and reproduction.
     
    Last edited: Jun 7, 2009
  7. Jun 7, 2009 #6
    One of the main issues with discussions whether viruses are living or not, is that we are trying to establish a discontinuous, essentialist barrier on what is most probably a continuous transition. None of the proteins, carbohydrates or lipids in your body are alive, however, in certain configurations together with other building blocks, something we call life emerge on a higher level of analysis (but of course completely explicable from these basic building blocks; no particular elan vital or life force).
     
  8. Jun 7, 2009 #7

    mgb_phys

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    Virii have inheritable traits that they pass on to their offspring so they are alive.
    They can't reproduce without a host cell but lots of species can't reproduce without a host body, from tape worms to cuckoos.
     
  9. Jun 7, 2009 #8

    DaveC426913

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    Logical phallacy: hasty conclusion. That is not the only criteria for life.
    [/QUOTE]
     
  10. Jun 7, 2009 #9
    all living systems depend on some external factors beyond their control for survival. we depend on the sun for energy. are we therefore not really alive?

    reproduction and the ability to evolve are the 2 most basic necessities for life. but like all categories, inclusion within the category 'living' is not all or nothing. see the wikipedia article on 'fuzzy logic' for more on that idea.
     
  11. Jun 7, 2009 #10

    CRGreathouse

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    I'd like to see some examples of creatures that can't reproduce on their own -- I'm sure there are some corner cases. That might be an illuminating comparison.

    Grammar nazi alert:
    1 virus, 2 viruses; 1 criterion, 2 criteria.
     
  12. Jun 8, 2009 #11
    Whatever you say, Freud.
     
  13. Jun 8, 2009 #12
    Hard to evolve if you cannot reproduce.
     
  14. Jun 8, 2009 #13

    DaveC426913

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    :bugeye::tongue2:
     
  15. Jun 8, 2009 #14

    DaveC426913

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    Then you don't believe in:
    1 forum, 2 fora
    1 vox, 2 voxen
     
  16. Jun 8, 2009 #15

    Andy Resnick

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    1 mongoose, 2 mongooses
    1 axis, 2 axes

    This is fun!
     
  17. Jun 8, 2009 #16
    Every living this is dependent on something, as has been said. I don't think that virii require host cellular machinery is sufficient to rule out virii are "alive".

    Really, this could all be straightened out if we had a better definition of life.
     
  18. Jun 8, 2009 #17

    DaveC426913

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    But it's more than merely a dependency. Sorry, I can't back that up with facts...

    (Sorry phil, but I gotta: :tongue:) This is kind of stating the exceedingly obvious. No discussion of "is a virus alive" in the history of the universe has gone more than 3 nanoseconds before resulting in the question "what is the definition of life"? And it's never been satisafactorily answered.
     
  19. Jun 8, 2009 #18
    what is your point exactly?
     
  20. Jun 8, 2009 #19
    Good question. Thank you. (A nice break from what I had planned to do.:cool:) What came to my mind is a quote, "Viruses today spread genes among bacteria and humans and other cells, as they always have... We are our viruses " by Lynn Margulis, 1998, Symbiotic Planet: A New Look at Evolution, Basic Books, 1998. p 64. This link tells you about Lynn Margulis. If you would like more information about her I can provide it.:smile:
    http://en.wikipedia.org/wiki/Lynn_Margulis

    And what a fasinating and awe inspiring world it tiss even when one is flat out tired from a four day wedding event of a good friend.
     
  21. Jun 8, 2009 #20

    mgb_phys

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    No - but it's a good one :biggrin:

    The question is of course - what is life? I was just putting forward one definition.
     
  22. Jun 9, 2009 #21
    That's more of a definition of one of the factors in a list of criteria for life. That sole statement has never been a definition of life in itself.
     
  23. Jun 9, 2009 #22
    Reproduction is already included in the criteria for evolution, so it is uncalled for to state it a second time.
     
  24. Jun 9, 2009 #23
    Good answer. The question is too. :smile: What is life?

    Here's an excerpt from NASA-Astrobiology Roadmap, Goal 3: Understand how life emerges from cosmic and planetary precursors, Perform observational, experimental and theoretical investigations to understand the general physical and chemical principles underlying the origins of life:

    Science is my baby! I just love it!
     
    Last edited by a moderator: May 4, 2017
  25. Jun 9, 2009 #24

    DaveC426913

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    Except that it is a definition of organic life.
     
  26. Jun 9, 2009 #25

    mgb_phys

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    There are self-catalysing chemical reactions for which this is true.
    there are even a couple of them that take different pathways depending on external conditions and so can be said to adapt. But they don't pass on the 'chosen' properties so don't have inheritance.
     
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