Dinos, Humans Out of Africa: Why There?
Turns out we humans have something in common with dinosaurs: We all trace our origins to Africa. Or at least it seems that way with the new discovery of a new early lineage of dinosaurs from Africa. But is there more to the story? Is there something special about Africa that makes it a cradle of consequential species?
Absolutely! Yes. In a way. I mean, sort of. Um…no, not really. The truth is, it depends on how you look at it.
There is definitely something very special about the old blocks of continents that have survived billions of years. They shift about the planet, form supercontinents now and again, wander off on their own, and all the while carry around in their rocks and strata many of the chapters of Earth’s history. And sometimes, as the rocks are being chipped away by erosion and tectonics, they those chapters are opened for geologists and paleontologists to read.
The chapter about African dinos, as we now see, is a very cool one. But it’s not really African, but Pangean. When the beast that would become dinos roamed the Earth, the supercontinent Pangea was still intact. An animal did not have to swim or fly to get from Africa to South America. They could walk. In fact, similar fossils found on both continents were early evidence of plate tectonics.
Something that the African section of Pangea of 240 million years ago seems to have in common with the Africa of 2 million years ago (when we evolved) is a warm climate. So that’s another thing we have in common with most dinos: we are warm-weather creatures. But then, so are flies and cockroaches and lots of other species that are arguably not very consequential.
And while we are on the matter of “consequential,” let’s get something straight. Dinosaurs existed as a large and changing group of animals that lasted for more than 100 million years. We, for all our planet-altering power, are a single species and have been around for 2 million years. Any old microbe can alter a planet (by making oxygen, for instance, as happened on early Earth). But to last 100 million years — that’s consequential.
But anyway, the bottom line is, yes, there is something special about Africa. But no, it’s not that the land has any special “important” species-making qualities that are different than other continents. Rather, it is special in the way any place is when the history of life is preserved in the rocks — a truly magical thing, if you think about it.
IMAGE: In 1858, geographer Antonio Snider-Pellegrini made these maps showing his version of how the American and African continents once fit together. (Courtesy of University of California, Berkeley)