The Mediterranean . . . it’s got these couple of problems. It’s a respectable-sized sea, y’know; it covers an area of 970,000 square miles (2.5 million square kilometers). That much surface area, you get a lot of evaporation. Now, that’d be ok, I mean, some of it rains back in, some comes back in rivers, but the thing is . . . it doesn’t rain all that much . . . relatively speaking. And the rivers that feed into it, they’re a bit on the wimpy side . . . relatively speaking. All appreciation to the Nile for its awesomely important history and everything, but it ain’t no Amazon.
So that’s problem number one. Problem number two: the Earth is molten inside. More specifically, what we call the Earth’s crust—land and ocean bottom—is mostly a thin skin of solid rock floating on melted rock that’s ever-so-slowly churning this way or that, taking big floating hunks of crust with it wherever it happens to be going. Hunks like Africa. Africa’s been floating north-easterly for a while now; a few million years, in fact. So, not very fast, but fast enough to become a problem. Because, y’know how that Straight of Gibraltar is kind of narrow? All it’d take would be for Morocco to hook up with Spain, close the straight, and guess what? Way more water evaporating into the sky than comes back in through rivers and rain. Let that go on long enough, whadda you think’s gonna happen? Thing is, it actually has. More. Than. Once. Continue reading →
John Hawks is a paleoanthropologist at the University of Wisconsin, Madison. In winter of 2014 he offered a 7-week MOOC (“massively open online course”) through Coursera, entitled Human Evolution: Past and Future. Superbly done, offered for free, the course included 71 videos, most of them interviews with people who are actively working in the wide array of fields essential for discovering the evolutionary lineage that led to us. The conversations weave together what we currently know about our origins and the methods that are used to uncover it. You also get to see that these people, for whom this is their life’s work, love what they do.
Many of Coursera’s already-completed courses allow you to sign up even after their end date, so you can access the videos and course material. Unfortunately, this is not one of them. Everything is still there, but it can only be seen by those of us who enrolled before it finished. At some point in the next year or two, the course will be updated and offered again, and you can ask to be notified when that happens. In the meantime, more than two dozen of its videos can now be seen at Prof. Hawks’ youtube channel.
Clive is director of the Gibraltar Museum, Geraldine is an archaeologist, and they describe what they’re finding at two excavation sites: Gorham’s Cave and Vanguard Cave. At the extreme western edge of the Mediterranean, in layers of sediment dated to about 32,000 years before present, these caves hold what is currently the last known evidence anywhere for the presence of Neandertal peoples.
Towards the end, Geraldine comes to the remains of a single event in the life of Gorham’s Cave—fragments of charcoal from a small fire, along with mussel shells and flakes from stone tools—revealed when layers of sand were removed, exposing what lay underneath.
At that time, the world was in an ice age. With so much water imprisoned in glacial ice, sea level was much lower. These days, the Mediterranean is quite close to the mouth of the cave. Back then, it would have been a half kilometer to a kilometer or more away, depending on which direction you headed. Even so, the cave received so much wind-blown sand that anything left inside, by animals or people, was quickly covered over.
It’s for things like this, that I love these conversations so much.
17:11–18:52
GF: This is the beauty of this cave, This cave gives you events that are maybe hours or days long at most. So you’ve got this group of possibly two individuals, they come in with their little bundle of mussels that they have foraged nearby on the coastline. We don’t know exactly where the coastline would have been, but it can’t be very far ’cause you don’t carry seafoods for very long ’cause they spoil very easily.
And they come into the cave, they build a very small fire. There’s not much charcoal left from that fire, and there’s not much alteration on the sediment, so there wasn’t a huge heat on that fire, probably just enough to open those mussels. They consume the mussels. Once they’re there, they’re retouching the lithics that they’re using—their stone tools. They take those away with them, when they go, but they leave all the debitage behind. And then that’s it, y’know. They’ve gone.
So this might– they may have stayed overnight, or it may have been, y’know, just a brief few hours, but the fact is when they go, the sand covers it up, and it’s left there untouched until we come along and re-excavate it. I think that’s a huge resolution. I mean, that is unique, I think.
JH: It’s completely remarkable.
GF: It’s beautiful.
JH: It is the closest that we come anytime in this to seeing what somebody’s life is like…
GF: Absolutely, yes, yes.
JH: …and that I think is just amazing.
GF: It tells us a lot as well, because it tells us that they needn’t necessarily have always been sitting around, y’know. They move from place to place. They stopped temporarily, had a quick picnic, and then carried on, y’know? And in this particular case, it was just two individuals. There’s no evidence it was any more than that.
