Out of Africa: The Origin of Our Species (Part 6)

Homo Sapiens

Note: I started reading Africa: A Biography of the Continent by John Reader. The following posts will basically summarize what I find interesting in the book as I’m reading it. None of the ideas or thoughts are of my own.

The source of raw materials used by Homo Habilis (Part 4) to make stone tools was never much more than 4km away, but Homo Erectus (Part 5), 900,000 years ago, was making tools from stone found more than 8km away. And 600,000 years ago, some of the material for stone tools was brought from 15-20km away. These distances weren’t easily covered within a day, which indicates that Homo Erectus must have been planning activities several days ahead for a journey to obtain raw materials. Also, the materials may have not been carried over the entire distance by members of a single group; the distribution pattern could indicate that some form of barter or trade was taking place among groups camped closest to the sources of the materials.

Figure 1 - Stone blade knife

Homo Erectus was the longest surviving and most widely dispersed of the ancestral toolmakers. The species disappeared from the fossil record around 200,000 years ago, and the biface technology it introduced cease to dominate the archeological record at roughly the same time. Instead, small flake tools, scrapers, and blades took over, which signify another drastic advance in toolmaking technology (Figure 1). It is as though the mind’s eye had looked beyond the primary needs of life and seen a multitude of secondary needs. Animals were no longer simply food, but also a source of skin that could be fashioned into into bags and coverings; trees supplied bark from which string could be twisted, and gum for fixing stoned blades to wooden shafts. But is there a variation in species in our fossil records that might accompany this development in toolmaking? Yes, at about 400,000 years ago a variation on the Homo Erectus appears, which is very similar overall to the existing species, but with differences in the configuration of the skull and face that are related to a significant increase in brain size. The brain averages 1,250cc, which is very close to the modern human average, and so the newcomer is called “archaic Homo Sapiens.”

Time (millions of years) vs. brain capacity (cc)

The archaic Homo Sapiens remain until a third hominid makes an appearance about 130,000 years ago. The skeleton of this third hominid is tall and slender, the face is short and tucked in under the skull, there is a high forehead but no brow ridges, and the brain measures between 1,200 - 1,700cc. This is the first evidence of ourselves, anatomically modern humans, Homo Sapiens Sapiens.

Where do we go from here?

Watch: The Journey of Man by Spencer Wells.