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Definition of species under attack?

  1. Apr 27, 2013 #1
    I learned that two sexual organisms are considered different species when no two organisms having their respective DNA structures could interbreed to produce viable offspring. Put another way, when looking it up, I find the definition:
    But then I read that:
    (a) Neanderthal interbred with homo sapiens to give part of today's modern man
    (b) Neanderthals is a different species from homo sapiens.
    Hence, the above definitions don't seem to hold. Can someone correct these definitions in light of this?
  2. jcsd
  3. Apr 28, 2013 #2


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  4. Apr 28, 2013 #3
    Thank you for your reply and the links, atyy.
    If I understand correctly (no guarantee of that), all the links you sent all roughly say that it is a fuzzy area:
    (1) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1692208/pdf/9533126.pdf leans towards "Biological Species Concept", similar to my rough definitions but nuanced due to unusual cases,
    (2) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC33696/ leans more towards a phylogenetic interpretation of species whereby physical features are the primary criteria which are of course influenced by genetic isolation
    (3) http://www.pnas.org/content/96/13/7117.long says that whichever concept you take, it is still not clear whether the Neanderthals were indeed a separate species.
  5. Apr 28, 2013 #4


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  6. Apr 28, 2013 #5

    Perhaps you have heard of ring species



  7. Apr 28, 2013 #6
    Thanks, atyy. Very interesting article.
    thorium 1010: very interesting about ring species; no, I hadn't known.
    As far as the other Wiki article you cited, the one you quoted, read a bit further down, where it says
    That cleared the way for the more recent articles (such as the article that atyy just cited) which continue to test the assumption that interbreeding may have occurred.
  8. Apr 28, 2013 #7
    Sure, but would you call something 99.5% similar to us, a different species ? Thats the important question, where would draw the line for species ?

    Species in biology is somewhat of a grey area, it is not black and white as we think it is.
  9. Apr 28, 2013 #8
    Indeed, that was my original question, and the answers showed me that it is indeed a fuzzy concept.
  10. May 9, 2013 #9
    I think the fact that there is small amounts of Neanderthal DNA in modern Europeans proves that Neanderthal were not a different species in the classic sense of "species".

    I think what happened was that there was a minor amount of inner breading but mostly the Neanderthal were out competed. In those days, 30K yeas ago, I think the Neanderthal population would have been equilibrium with the food supply. Then come these other guys who like to eat the same food. We modern humans eat their food so they remained in equilibrium with a shrink food supply. And I'm sure there was a very rare hybrid born now and then.
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