Sunday, August 27, 2017

Cavemen Rule, Part III: Lucy, et al.

Today: Cavemen Rule, Part III: Australopithecus.

But first, a disclaimer: today we’re going to be covering a huge period, on the scale of millions of years, in just a few minutes.  That’s not because this period is any less interesting or worthy of study than others, but because I want to focus more on the emergence of “people” as we think of them—that is, in the words of paleoanthropologist John Shea, behavioral variability.  But to really enjoy the wonder of “personhood’s” emergence, we need a little background information, which will be covered in this video, and the next.  Let’s start by jumping into our Wu-Tang Elevator and going back to the Africa of around three MYA…

So as we begin to explore our surroundings, we become familiar with a few different creatures that belong to what we know as the genus Australopithecus, or “Southern Ape” in Latin.  We would have seen these guys as decidedly more chimpanzee-like than human-like, with one important difference: Australopithecus walked upright (1). 

There were a few different species of Australopithecus, and they seem to have been around generally between four and two MYA.  The different species show variation according to a theme that is very, very important in the study of human origins: robustness vs. gracility.  That is, a heavier-set build as opposed to a lighter, less brawny physical morphology.  Consider, for instance, the robust gorilla, as opposed to the gracile bonobo.  Gorillas live in dense jungle, where you don’t really need to run from anything, and rely on tough, hard-to-chew stems and shoots (2).  The forests inhabited by the bonobo, on the other hand, are less dense, and they rely on softer, easier-to-chew fruits (3).

Australopithecus lived on the savanna, rather than in the forest (4), which made it necessary for them to stand up to look out over the tall grass.  Australopithecus was therefore evolutionarily pressured by a treeless environment for greater gracility.  Since they were less brawny, they became more reliant on tools.  This set of traits gradually led to the emergence of the genus homo about 2.8 MYA.
So what was Australopithecus like?  Most of us are familiar with the iconic Lucy, discovered in 1974:

When I was a little kid, I saw this picture, and mistook the jawbone for her smiling.

When she was alive, she probably looked kind of like a chimpanzee that stood upright:

Although Lucy is a lot more famous, we also have a beautiful skull of an infant Australopithecus from Ethiopia that its discoverers have named Selam, or “Peace”:


Here’s what she looked like when she was alive.  I actually think she was on a National Geographic cover a while back, so maybe you’ve seen her before:

Aw, she’s so cute!  I wanna give her a hug!

When paleoanthropologists examine this wonderfully preserved skull, along with others that we’ve found, it becomes clear that their skulls were a lot more like those of chimpanzees than humans.  For instance, their brains appear to have been comparable in size to those of modern chimps (5).  Their behavior was probably not much more “human-like” than chimpanzees either, although it was recently discovered that they were able to use stone tools (6):

On the other hand, there is one, very compelling, piece of evidence that there was, even then, just a spark of something incredible going on in the brains of these creatures.  It is possible that among Australopithecus abstract thought, the idea that one thing could represent another thing, was already in its infancy.  At a site associated with Australopithecus fossils in Makapansgat Cave, South Africa, an unassuming jasperite pebble was found, which was naturally shaped in such a way that it crudely resembles a humanlike face.  Now of course, there’s lots of natural stuff that looks like other stuff, just think of clouds in the sky!  But the eerie thing about the Makapansgat Pebble is that it is of a geologically different composition from the surrounding environment (7).  The nearest source of jasperite is miles away.  The chances of it somehow getting to Makapansgat by itself are astronomically, negligibly small.  It had to--and even as I say this, I get chills up my spine—It had to have been carried there.

The pebble is small enough to carry without any trouble—half a pound—and could have been held easily in one hand.  It would not have made a very good tool, given its shape, and certainly not one useful enough to carry miles away from its source.  What appears to have happened is that somewhere around 3 million years ago, an Australopithecus found this thing, looked at it, and a synapse fired somewhere in his little monkey mind, flashing like lightning on the horizon.  He found this pebble, thought, hey, this looks like me—an abstract thought—and considered this interesting enough to take back to camp to show his friends.  I wish I could’ve been there to see him find this thing.  I’d give a million dollars just to find out exactly what went through his mind, and what significance it had.

Would you like to see it?  Of course you would.  Here it is: the oldest face in the world:

I love this.  When we look at this pebble, we experience exactly the same jolt of recognition, and see exactly the same face and features, that someone saw three million years ago.  Isn’t that cool?  So we see, even at this early stage, the faintest flickers and glimmers of what would, someday, make us “people”.

Next time, we’re going to talk about the transition from Australopithecus to Homo, and what we know about the very earliest members of our genus.


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