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| F. The Origins of Modern Humans (c. 150,000 to 100,000 Years Ago) |
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| Homo sapiens sapiens means “wise person.” We are the clever people, animals capable of intelligent thought, of manipulation, of subtlety. A great biological and cultural chasm separates us from archaic humans. This chasm comes from our ability to speak fluently, to pass on knowledge and ideas through the medium of language. Consciousness, self-awareness, foresight, and the ability to express one's emotions—all are the consequence of articulate speech. These qualities can be linked to our capacity for symbolic and spiritual thought. We modern humans are concerned not only with subsistence and technology, but with defining the boundaries of existence and the relationship between the individual, the group, and the universe. Fluent speech, the full flowering of human creativity expressed in art and religion, expert toolmaking—these are some of the hallmarks of anatomically modern humans. With these abilities, humankind eventually colonized not only temperate and tropical environments, but the entire globe. We are now concerned with people biologically identical to ourselves, with the same intellectual abilities and potential as ourselves. | 1 |
| One of the great controversies of archaeology surrounds the origins of Homo sapiens sapiens. One group of scholars believes that Homo erectus populations throughout the world evolved independently, first into early Homo sapiens, then into fully modern humans. Thus, the modern geographic populations (races) of the world would have been separated for a long time, perhaps a million years. Most experts take a diametrically opposite view. They hypothesize that Homo sapiens sapiens evolved in Africa sometime between 200,000 and 100,000 years ago, then spread to other parts of the Old World. Under this model, modern geographic populations are less than 100,000 years old. | 2 |
| These two models represent extremes, which pit advocates of anatomical continuity against those who believe there was population replacement. Each model is based on the minute study of human fossil remains, but the replacement theory also relies on studies of mitochondrial DNA (mtDNA). | 3 |
| Molecular biologists like Alan Wilson and Rebecca Cann have studied the human family tree using this form of DNA, which is inherited through the female line without being diluted with paternal DNA. Thus, they argue, it provides a unique tool for studying ancestral populations. They compared mtDNA from Africans, Asians, Europeans, and Southeast Asians and found that the differences between them were small. They formed two groups: one was the Africans, the other the remainder. Wilson and Cann concluded that all modern humans derive from a primordial African population, from which populations migrated to the rest of the Old World with little or no interbreeding with existing archaic human groups. | 4 |
| By calculating the rate of mtDNA mutations, they argue that archaic Homo sapiens evolved from Homo erectus in Africa by about 200,000 years ago. Then Homo sapiens sapiens, anatomically modern humans, appeared some 140,000 years ago. | 5 |
| Mitochondrial DNA is still controversial, but there is some archaeological evidence from Africa that supports the biologists' scenario. Highly varied, early Homo sapiens populations flourished in sub-Saharan Africa between 200,000 and 150,000 years ago, some of them displaying some anatomically modern features. At the Klasies River Caves on the Indian Ocean coast of South Africa, anatomically modern human remains date to between 125,000 and 95,000 years ago. They are associated with sophisticated, versatile tool kits that were, if anything, superior to those used by the Neanderthals in Europe at the time. | 6 |
| Many scientists believe that Homo sapiens sapiens, modern humans, did indeed evolve in tropical Africa sometime after 150,000 years ago, as the geneticists argue. Ecologist Robert Foley has theorized that modern humans evolved in a mosaic of constantly changing tropical environments, which tended to isolate evolving human populations for considerable periods of time. Some groups living in exceptionally rich areas may have developed unusual hunting and foraging skills, using a new technology so effective that they could prey on animals from a distance with finely made projectiles. With efficient technology, more planning, and better organization of both hunting and foraging, our ancestors could have reduced the risks of living in unpredictable environments in dramatic ways. And, when climatic conditions changed, and hitherto isolated populations mingled with others, the process of biological and cultural evolution accelerated. | 7 |
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