February 22, 2012

THERE'S NO SUCH THING AS SPECIES:

Race Finished (Jan Sapp, March-April, American Scientist)

Race?: Debunking a Scientific Myth is a beautifully presented book, elegantly reasoned and skillfully written. Tattersall, a physical anthropologist, and DeSalle, a geneticist, are both senior scholars at the American Museum of Natural History. Their aim is to explain human diversity in terms of human evolution and dispersal since our ancestors walked out of Africa some 100,000 years ago. The patterns of diversity, they write, reflect the processes of divergence and reintegration, the yin and yang of evolution.

In biology, a grouping has biological meaning based on principles of common descent--the Darwinian idea that all members of the group share a common ancestry. On this basis, and on the ability to interbreed, all humans are grouped into one species as Homo sapiens, the only surviving member of the various species that the genus comprised. Species are arranged within the "tree of life," a hierarchical classification that situates each species in only one genus, that genus only in one family and so on. Nothing confuses that classification more than the exchange of genes between groups. In the bacterial world, for example, gene sharing can occur throughout the most evolutionarily divergent groups. The result is a reticulate evolution--a global net or web of related organisms, and no species. Among humans, reticulation occurs when there is interbreeding within the species--mating among individuals from different geographical populations. The result of such genetic mixing of previously isolated groups--due to migrations, invasions and colonization--is that no clear boundaries can be drawn around the variety of humans, no "races" of us.

The data for tracking lineages come from genomics, DNA comparisons and the study of genetic markers. Tattersall and DeSalle argue that not only are the differences between the classically defined "races" very superficial, they are also of surprisingly recent origin; the variety of human populations seems to have both accumulated and begun to reintegrate within the past 50,000 to 60,000 years. The diversity among us has arisen in a blink of evolution's eye. The process of relative geographic isolation of local populations into what might have been true races (genetically differentiated populations) during the last Ice Age began to reverse as formerly isolated human groups came back into contact and interbred. That reintegration, which has occurred intermittently throughout human history, is sped up today because of great migration and widespread mating of individuals from disparate geographic origins. The result is that individuals identified as belonging to one "race," based on the small number of visible characters used in historical race definitions, are likely to have diverse ancestry.

Nothing became modern Darwinists like their willingness to abandon any coherence to their theory in favor of Christian morality .  Faced with the realization that you couldn't be both decent and Darwinist they overwhelmingly chose the former.  Sure, it left the theory in tatters, but it made them better people. Bully for them.

Posted by at February 22, 2012 6:44 AM
  

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