On the Evolutionary Trail

http://www.nytimes.com/2016/09/24/opinion/on-the-evolutionary-trail.html

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It began during one of those periods many millenniums ago when a recurring wobble in the Earth’s axis brought rains to the deserts of Africa, the Sinai and the Arabian Peninsula. This enabled hunter-gatherers to follow their prey out of Africa, the continent on which they had evolved between 200,000 and 100,000 years ago, and to become the master species of the entire world. With time, their exceptional powers of intuition enabled them to develop progressively more sophisticated tools not only for hunting and warring, but also for trying to learn who they were and how they came to be.

That is the dual wonder instilled by the articles in the journal Nature about the extraordinary findings of several groups of scientists on human evolution: first, that at last we can say with almost total certainty that the ancestors of us all — Native Americans, Australian Aborigines, African Pygmies, Mongolian Sherpas, Cree Indians — descend from a single migration out of Africa 50,000 to 80,000 years ago. And second, that these creatures went on to create scientific tools like DNA analysis and computer modeling, first introduced only decades ago, that allow them to retrace their evolutionary trail.

The three teams reporting in Nature sequenced the genomes of 787 people in far-flung indigenous populations, including Aboriginal Australians and people in Papua New Guinea, and all came to the same conclusion, providing something of a unified theory of human dispersal. In a fourth study, researchers reported on a computer model of Earth’s climatic history that pointed to the periodic greening of African and Eurasian deserts, which created corridors for migration.

There were human subspecies, like the Neanderthals or the Denisovans, who crossed into Eurasia at different times. But they vanished, leaving behind only a trace in Homo sapiens. Now there is the fear that this victorious species, literally “wise people,” may have failed to evolve the wisdom to keep pace with its omnipotence and could inadvertently destroy Earth and all that lives upon it.

Perhaps a better understanding of where we came from and how we got here will increase the chances for survival of our world. In the meantime, it is enough to celebrate yet another contribution to our knowledge about ourselves and the extraordinary process by which we came to be.