Re: Neanderthals' Noses Blow Scientists Away
Paul Smith (paul.smith@tip.nl)
Fri, 11 Oct 1996 21:35:25 GMT
susansf@netcom.com (Susan S. Chin) wrote:
>Nick Maclaren (nmm1@cus.cam.ac.uk) wrote:
>: In article <3253E8FD.3597@livingston.net>,
>: Don Staples <dstaples@livingston.net> wrote:
>: >
>: >Species identification needs more precision than the limited factor of
>: >singular observations. I beleave that there are enough racial
>: >differences in modern man to allow destinction by race from skeletal
>: >structure, but all HS.
>: Yes, there are. It is trivial to separate most populations and often
>: easy to distinguish even individual skeletons. In fact, I am 90%
>: certain that you can separate mainly celtic groups from mainly
>: germanic ones on the basis of the skulls alone! The same is true for
>: many geographical variants of other mammals.
>This brings up the question of the amount of morphological variability
>that can be accomodated into one species.
I can't give you chapter and verse on this, but I remember reading
that morphological variation between some species of anurans can be as
low as zero but that you still have two species becuase they're
reproductively isolated, and, therefore, potentially able to evolve
away from each other. This, it seems to me, is the essence of what a
species is, and if morphological variation doesn't affect the ability
to interbreed and produce fertile offspring any ammount of it can,
presumably, be maintained in a single species.
Homo sapiens sapiens today
>displays a wide range of morphological differences often expressed
>in terms of race or geographical variants.
>But is it safe to assume that ancestral hominid species would have similiar
>levels of variation? I don't think so, and as the fossil record shows,
>they don't. The level of morphological variability observed in H.s.s. is
>likely unique to our species and a result of greater geographical
>dispersal than our predecessors, thus the opportunity to develop
>recognizable regional differences....
>I'm not saying anyone here is doing this, comparing Homo sapiens sapiens
>variability with fossil taxa, but it is something often seen in discussions
>of species. But is it valid. And do morphological differences always
>mean or imply the "same" thing. There obviously aren't any clear
>answers that I know of here. Just wanted to see what interested and possibly
>better informed parties think about this.
>Susan
>--
> susansf@netcom.com
Perhaps one of the problems in this debate is simply that, because it
involves humans, people want more stringent criteria before a seperate
species is called and close relatives are cast out of the human family
as it were. If we were dealing with fossil freshwater mussels, it
would be enough to apply multivarate analysis to different features,
and, if the measurements tended to group into two, three or four
modes, it would be accepted - in the absence of evidence to the
contrary - that there were two, three or four species represented in
the sample, even though it wouldn't prove that there was no gene flow
between the species (becuase these distinctions could be maintined by
natural selection).
Is there enough data to distinguish Neanderthals and Cro-Magnons in
this way? Maybe, but, as I said, morphological grouping doesn't prove
different species. But to get more certainty about this separateness,
supporters of "Neanderthals 'R' Us" multiregionalism would probably
want to be shown that they were two *biological* species involved
before they changed their minds. Since it's always going to be
difficult to prove a negative - in this case, the absence of hybrids -
I think the onus is on multiregionalists to demonstrate convincing
evidence of Neanderthal - Cro-Magnon hybrids from the time these
groups were known to have been in contact. There would then, I hope,
be no doubt that Neanderthals should be Homo sapiens neanderthalis.
Met vriendelijke groeten!
Paul.
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