Re: DISCOVER/Neanderthal/Homo Sap.

Erin Miller (ermiller@tezcat.com)
5 Sep 1995 00:19:24 -0500

In article <42f6h3$a1j@rebecca.albany.edu>, <cc3265@CNSVAX.ALBANY.EDU> wrote:
>In article <42dplj$530@huitzilo.tezcat.com>, ermiller@tezcat.com (Erin Miller) writes:
>>
>>They are "different" differences. Dogs have been rapidly and artificially
>>bred to create extreme differences, at the same time as intentionally
>>keeping them "breedable." Also in dogs, the skeletal differences are
>>largely (tho not 100%) of the skull. When you look at the postcranial
>>skeleton of a Great Dane vs. a Yorkie, the differences are largely of size
>>and not much else.
>
>That's true. But the same could be said of modern humans and Neandertals,
>could it not? The skulls are definitely different, but, postcranially
>differences are largely that of size and bone thickness, as far as I
>have heard. If you know of something more, I'd really like to know
>about it.

Yes, there are differences. Robusticity is one, curvature of the long
bones is another. There are even differences of individual bones, such as
the distal phalanx of the first manual ray (ok, ok, the end thumb bone
;-) is significantly larger and flatter. The pelvis is shaped slightly
differently, and there are others.

>> To perhaps explain with a counter example: there are LOTS of
[snip]
>
>So, are you saying that these animals are a better model to go by? Or are
>you arguing that there is really no way to determine from skeletal remains
>alone whether any two animals are in the same or different species?

The latter. Because we can see cases of it in both: animals with
virtually identical skeletons that are not even in the same genus, AND
animals that are the same species but with a great deal of variation,
there is no way to know for SURE.

>> Can most people tell the difference between the skeletons of a common
>>marmoset, a lion tamarin, and a cotton-top tamarin? The skeletal
>>differences are *minimal* to the utmost, yet none of these primates are
>>even in the same genus.
>
>Again, this would seem to indicate we cannot classify any fossils with
>surety.

Yup, IMHO.

>
>Also, with humans, you really do have to contend with sexual selection.
>Certain cultural groups might prefer mating only with each other, and so
>on. So, in that sense, the selectively bred dogs might be a better model
>than wild animals. Humans do tend to be (somewhat, and some more than
>others!) selective about who they breed with.

Yes. The *might* be a better model, but we'll never really know for sure.

>> So it is not so simple as taking an anecdotal example (ie: domestic
>>dogs) and trying to apply it as the rule. That is also the reason why one
>>cannot apply the arguement that "they lived in proximity for a long time,
>>so they must have had sex." No more so than a common marmoset would want
>>to 'have sex' with a lion tamarin.
>
>No, I agree. You cannot take either example as a general rule. It is
>difficult (though I don't believe impossible) to classify fossils that
>have no living models. That is why I am arguing that the only sure way
>to "split" would be along the lines of functional differences. Radical
>differences in anatomy, to the point that they obviously functioned
>differently, would mean the creatures were occuping different econiches,
>using different subsistence strategies, and so on. Splitting any other
>way just invites contention and confusion (and I have to teach this stuff
>to freshmen!).

I think that makes a lot of sense. I guess I could see splitting along
the lines that Tattersall proposes (if you see morphological differences,
then they are different species) if I were convinced that the vast,
overwhelming majority of species fit into that category. But I am not
well versed enough in that to know. I could take Tattersall's word for it
(a pretty easy thing to do, IMHO), but I would want to look into it more
for myself, first.

> I would like to comment further on this, but I just had company show up
>at the door! I'll take it up again in the next post.

I look forward to it.

-erin

--

  "On the internet nobody knows you're a dog ...

  but damn if everyone won't know what your cat looks like."      -fatz



  Erin Miller                 http://www.tezcat.com/~ermiller/erin.html

  University of Chicago / Anthropology Department / ermiller@tezcat.com