Re: What are race promoters promoting?
24 Nov 1996 17:37:39 GMT

Susan wrote:
>My understanding is that races are geographical variants of a species.
>The morphological differences between populations become greater the
>farther apart these populations are.

This understanding runs into a lot of problems. Ituri pygmies, Bantu,
!Kung Bushmen and so on all share geographic proximity and are all
considered part of the "Black" race in the "3 race" typology you put
forth, but they are divided by profound phenotypic differences. What they
have in common is a dark skin pigment and residence on the continent of

>The similarities between populations
>are due to similiar adaptations to environmental demands.

Since humans use culture to do the bulk of their adapting, actual
adaptational differences are few (like the sickle cell trait). Most other
so-called adaptations to climate are the result of phenotypic plasticity
or non-adaptive factors like gene drift and the founder affect.

>This racial
>differentiation occurred once early hominids spread beyond Africa and the

>Old World.

This is certainly one view of human origins -- that Homo erectus evolved
seperately into H. sapiens in different places. This theory has a number
of problems. One is that DNA comparison suggests a much closer
relationship than that. Another is that this scenario (various H. erectus
species evolving in isolation) would more likely lead to actual
speciation. If this had happened, the "races" would not be able to
interbreed at all. Finally, the assumption that H. erectus was somehow
"driven" to involve into H. sapiens wherever they were implies a sort of
directional evolution which few biologists credit these days.

> Limited interbreeding between populations lead to these
>phenotypic differences which we can easily recognize as a "racial type,"

First of all, I think you must mean genotypic, for if all differences are
phenotypic, there would certainly be no races. There is unquestionably
genotypic variation within and between human groups -- it just doesn't
break sort into easily identifiable "racial" groups unless skin color is
your single criterion.

Another view (from the one you propose above) is that there has been
considerable gene flow throughout human history, and that humanity
represents a continuum of physical variation which we arbitrarily divide
into artificially discreet races.

>physical anthropologists recognize 3 major groups.

The vast majority of Physical Anthropologists do not recognize this and
have not for many decades.

> Subsequent migrations
>have obviously blurred the lines of what criteria should be used or can
>be used to differentiate the "races." But if looked at from the point of
>view of geographic origins, most humans today can trace their heritage
>back to one or more likely, several geographically distinct areas.

Again, this is an assertion which has never been demonstrated and which
much data (like skeletal analysis and DNA analysis) suggests is untrue.
It is one paradigm of many, and to survive it must be supported by better
evidence than alternative paradigms.

>Recognizing that races exist as a phenotypic category,

Again, you certainly mean genotypic here.

>one that doesn't
>always place individual humans neatly into clear categories either
>phenotypically or genetically, doesn't negate the fact that the
>differences we observe between people today are due to the geographic
>origins of their ancestors.

Again, this is one of many views and must be supported. Archaeological
and Paleoanthropological data bear out that there were once other SPECIES
of humanity, but there is no clear evidence that human variation used to
be greater than it is now, as you suggest. Again, analysis of DNA
suggests a closer genetic unity the farther back you go -- though I
readily admit that DNA analysis has some problems.

> Differences aside, we are more alike than we
>are different. We're all members of one race, that of the human variety.

I agree.


-- Greg Keyes