Hanging on to humanity

By now many of us are aware that recent research has shown that a small portion of every living human's DNA traces back to single woman in Africa - a woman dubbed "Eve." In addition, the DNA studies show that during a big-time glacial period lasting from 195,000 to 123,000 years ago, humanity damn near went extinct. (The numbers dropped from more than 10,000 breeding pairs of modern human individuals to just hundreds - one hell of a close call.)

So how did those few early humans hang on as the arid, cold conditions of that glacial stage (known as Marine Isotope Stage 6) made practically all of Africa uninhabitable by killing off the animals and plants that hunter-gatherers needed to survive? New research starting almost 20 years ago but culminating only recently has determined that those few humans who survived did so by living near the very southern tip of Africa. There they could make do on carbohydrate-rich tubers and bulbs of plants resistant to the cold and the rich protein found in shellfish thriving in the tidal waters.

I learned all this from an article in the August issue of Scientific American by Curtis W. Marean, a distinguished scientist who, with colleagues worldwide, has published the findings in 2008 and 2009 in the top scientific journals.

But what caught my eye was their solid evidence that humans were pretty darn smart a long, long time ago. European scholars over centuries had concluded that real thinking humans didn't emerge until some 40,000 years ago. They reached this conclusion because they dug only in Europe, and because, hey, there were nothing but savages anywhere else!

Some 160,000-110,000 years ago, on the tip of Africa, people saved themselves by figuring out how to survive in one of the only environments that offered them hope. They almost had to have a calendar (based on lunar phases) to determine when the lowest tides made collecting shellfish safest. They created ochre paints for aspects of culture that were clearly symbolic. And they invented complicated ways to heat certain stones in certain ways to manufacture special stone spearheads - knowledge that took smarts to pass down through generations, probably through speech.

The researchers have had to overcome the archaeology gospel that the Solutrean people in France invented heat treatment of stone about 20,000 years ago. It looks as though they have done so. Let's hear it for the really old guys, cracking shells and digging up tubers, watching the sea and the sky and the rocks around them, hanging on to humanity so we can, too.