Origens humana: da África

terça-feira, setembro 22, 2009

Human origins: Out of Africa

Ian Tattersall1

+ Author Affiliations

Division of Anthropology, American Museum of Natural History, New York NY 10024
Edited by Richard G. Klein, Stanford University, Stanford, CA, and approved July 16, 2009 (received for review March 23, 2009)


Our species, Homo sapiens, is highly autapomorphic (uniquely derived) among hominids in the structure of its skull and postcranial skeleton. It is also sharply distinguished from other organisms by its unique symbolic mode of cognition. The fossil and archaeological records combine to show fairly clearly that our physical and cognitive attributes both first appeared in Africa, but at different times. Essentially modern bony conformation was established in that continent by the 200–150 Ka range (a dating in good agreement with dates for the origin of H. sapiens derived from modern molecular diversity). The event concerned was apparently short-term because it is essentially unanticipated in the fossil record. In contrast, the first convincing stirrings of symbolic behavior are not currently detectable until (possibly well) after 100 Ka. The radical reorganization of gene expression that underwrote the distinctive physical appearance of H. sapiens was probably also responsible for the neural substrate that permits symbolic cognition. This exaptively acquired potential lay unexploited until it was “discovered” via a cultural stimulus, plausibly the invention of language. Modern humans appear to have definitively exited Africa to populate the rest of the globe only after both their physical and cognitive peculiarities had been acquired within that continent.

Homo sapiens evolution fossil record symbolic cognition


1E-mail: iant@amnh.org

Author contributions: I.T. designed research, performed research, and wrote the paper.

The author declares no conflict of interest

This article is a PNAS Direct Submission.


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