Origins

The din of politics is (rightly) dominating most of the attention market right now. But outside of the crumbling of our democratic norms, there is an absolutely fascinating story unraveling in the realm of archeology that is going largely overlooked relative to its consequences for our understanding of the origin of our species.

The standard model of the origin of homo sapiens that you probably learned in school is that we evolved in the “cradle of humanity” somewhere in East Africa, likely around modern Kenya/Ethiopia, about 200,000 years ago. Then we basically stayed there for about 130,000 years, until, sometime about 70,000 years ago, one or two small groups┬áventured northward, across the Sinai and into the rest of the world. People eventually spread to Australia about 50,000 years ago, and North America about 15,000 (Bering Strait land bridge, ice age, etc.). This single migration of just one group is why, so goes the theory, all other ethnic groups throughout the world have a remarkable level of genetic similarity relative to those of African descent. The level of genetic diversity within African populations today, and their descendants, is much, much greater than that between, say, modern Chinese, Indians, Europeans and Inuit. All of those subsequent groups basically descended from this very small population that left Africa in the first place. Put another way: Zimbabweans and Senegalese have much less in common genetically than a white American does with a Polynesian. This much is proven fact.

But a bunch of recent discoveries have challenged this origin model.

  • We know that the Neanderthals and Denisovans probably descended from a common ancestor with homo sapiens. Recent genetic research has shown that they interbred not only with each other much earlier (like, ~500,000 years ago, outside Africa), but also with modern homo sapiens. The weird thing is that we find evidence of this interbreeding with homo sapiens about 270,000 years ago, not 70,000, and in Europe. So… at least some homo sapiens were in Europe two hundred thousand years earlier than we’d thought.
    • Fun fact: the average modern non-African carries around 2.5% Neanderthal DNA. (Mine is perhaps a bit higher, according to a genetic ancestry test I took. My wife is not surprised.) The average modern African carries 0%.
  • Next: we’ve now also found fossils of ancient homo sapiens… in Morocco, not East Africa, that are over 300,000 years old. That’s ~100,000 years older than the earliest we’d previously found (in Ethiopia), and really far away. This really re-writes the whole theory. Homo sapiens would have to have evolved and then spread widely throughout Africa.

It’s becoming clear that, even if early modern humans did evolve primarily in East Africa, they didn’t just stay there. Different groups moved. We surely don’t even know the half of it yet.

Then, you get to the really crazy stuff.

  • Good evidence has now been found in Australia indicating human settlement 65,000 years ago, far longer than earlier thought. That time frame also indicates tens of thousand of years of human co-existence with Australian megafauna like the Diprotodon (the giant wombat), contrary to the standard assumption that humans quickly hunted giant creatures like this to extinction.
  • If you’re into really crazy stuff, try this: there’s evidence, albeit controversial, of settlement in North America about 130,000 years ago, which would put it well before modern humans are even supposed to have left Africa. The evidence of this theory is still thin, but worthy of consideration. (Basically, they found mastodon bones that had been smashed, marked and distributed in ways distinctive of stone tools.) If humans, or even proto-humans, were in North America that long ago, it changes a lot. The next-oldest hard evidence of settlement is over 100,000 years later, in Clovis culture sites in the Southwest.

It’s becoming very clear that we still don’t really know that much about the origins of our species. It’s possible we’ll never know the full truth. But the gradual uncovering of evidence is showing that humans (and Neanderthals, and Denisovans) were older, smarter and way more resourceful and resilient than the “cavemen” joke goes.

One of the themes I explore in The Second Transit is the slow process of an entire species discovering the exogenous forces that have defined its development. Something that fascinates me is how creatures of biological time (like us) grapple with and understand forces that act on geological or universal timescales. We can’t really do it, right? Creatures that only live and understand ~75 year lifespans can barely conceive of the lifespan of your average rock, let alone a species like the alligator, which has been around a lot longer than humans have. In “Second Transit,” the challenge the characters have is dealing with, and transmitting meaningful knowledge of, this asteroid that only shows up every 2,000+ years. How do you pass meaningful knowledge on to descendants hundreds of generations subsequent to you? Ozymandias would like to know.

A lot of people don’t care where or when humans came from, and I get it. It’s not very practical knowledge, I guess. Yet understanding our origins is central to understanding who we are as people and as a species. That understanding expresses itself in a vast number of ways (cue, the absurdist theories of race propounded by racist know-nothings). It’s the kind of foundational knowledge that provides the critical context for everything else you know. And it seems to me that knowledge like that is some of the most valuable you can learn.

 

 


I send out a semi-regular update with the more interesting stuff I've read and written. Learn more about it and read old issues, or just sign up below. I won't spam you - promise.

One Reply

Leave a Reply

Your email address will not be published. Required fields are marked *