Teepen: Frontiers -- past and present -- challenge humankind

Not all of our frontiers lie ahead. Some of the most enticing are in our past, and restless science, our innate curiosity about just who we are and how we got here from there, a cussed persistence – and a bit of luck – continue to push back the past's frontiers as surely as we press into space and subatomic physics.

Modern telescopes have taken us within a few hundred million years of seeing creation; their next generation might bring us a snapshot. Protein fragments from a dinosaur femur suggest that the chicken may have evolved – devolved? – from, of all creatures, Tyrannosaurus rex. ("Just who are you calling 'chicken,' buster?")

The latest news from the past is startling, and a bit scary.

DNA evidence has found – and, please, don't ask me how – that around 70,000 years ago, a long period of severe drought in southern and eastern African had reduced the early human population to only about 2,000. And those 2,000 were living in small, widely scattered groups.

To speak of "humankind" at that time would be presumptuous in the extreme. We were at the deadline of extinction.

We have known for many decades that we arose in east Africa; DNA has even traced all of us to a vastly ancient Eve some 200,000 years back. Now we are told that it wasn't until about 40,000 ago that the remnants from that catastrophic drought cohered into a pan-African population and began peopling Earth in earnest.

Imagine: And now we are 6.6 billion-plus, and counting. Fast.

Looking at the near-wreck that we have made of the planet and at the slaughters we have authored – the 20th century bloodbath alone could serve as a case against our propagation – it is tempting to think of us as nothing much better than a planetary plague.

In our compiling millennia, we have gone from nearly being taken out by natural disaster to bum-rushing our kind toward the potential for comparable disaster of our own creating. (See "warming, global.") It is a challenge to file that arc under "progress," no matter how many clever geegaws we have invented along the way.

But then you think of.. oh, I don't know. Any number of things: Egypt's awesome pyramids, Renaissance art and the cave drawings that led up to it, the scratch agriculture that got us here, Louis Armstrong and Earl Hines playing "Weatherbird," China's buried terra cotta legion, the very idea of a butterfly conservatory, microscopic surgery, the late Beethoven quartets, the elegance of a good curveball.

Now that we know of our escape, that close call 70,000 years ago ought to give us companionable empathy for the fellow creatures we similarly menace with our carelessness. It ought to be a standing warning against the arrogance that has us supposing we are Earth's favorites.

Those ancient 2,000, to whom we owe our chance, survived from stubborn instinct. We at least know, as they did not, that wherever it may finally lead, the one thing evolution must have to make good is time.

The 2,000 left us that. We owe it to them to pass it on. Frontiers surround our sort.

Tom Teepen is a columnist for Cox Newspapers. He is based in Atlanta.