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View Diary: How Homo sapiens Populated the Earth: Part Two (19 comments)

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  •  I just checked the article in Science News (5+ / 0-)
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    Youffraita, Pluto, blueoasis, Aunt Pat, JesseCW

    which discusses what I think you're referring to. It's not that the earliest members of Homo are from Asia. Rather it's that the line of primates from which Homo ultimately derived is of Asian origin, and there's good evidence for that. In the chapter on the evolution of primates in my book, I wrote:

    The evidence, therefore, seems to be shifting in favor of an Asian origin of the anthropoids. However, no conclusive judgment in this matter is yet possible. It would appear that the greatest likelihood is that anthropoids first evolved in Asia relatively soon after the evolution of the primate order itself. Several families of them appear to have colonized Africa, and from these African “immigrant groups” the line of animals that ultimately produced the African great apes emerged.

    As far as when specific anthropoid characteristics evolved, a group of researchers working in the area of Haplorhine evolution has put it this way:

    We do not know the order in which most of [the] crown anthropoid features evolved. Most features probably appeared in a mosaic fashion in stem anthropoids. Some features may be primitive for Anthropoidea or Primates as a whole and others may have evolved in parallel in multiple crown anthropoid clades. We do know that most of the hard tissue features…are evident in Afro-Arabian fossils of late Eocene age, although several taxa lack some derived features found in living anthropoids... We do not know the character states for many of the presumed Eocene anthropoids from Asia because they are not yet known from adequate cranial materials. Postcranial materials of putative Asian stem anthropoids have been found in isolation, complicating their specific attribution.42

    The concept of a developmental mosaic is key because it emphasizes again that evolution and adaptation are not nice, neat, linear, straightforward processes. There are a great many environments exerting a great many selection pressures over a very wide span of time and a huge stretch of geography. It took many millions of years to bring about the advent of the “advanced” anthropoid types. Traits emerge and disappear, the same trait emerges (although not in an identical fashion) in different animals living in similar settings, and behavioral routines evolve that either enhance reproductive fitness or detract from it. The story is only now becoming clearer, and many, many tiles in the mosaic have yet to be found.

    Read a preview of Volume One of my book here.

    by Yosef 52 on Sat Jun 22, 2013 at 12:39:24 AM PDT

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