The earth made us
Those are the last four words of “Origins,” by Lewis Dartnell. I recently read Darwin’s “Origin of Species,” and before that “Guns, Germs and Steel,” Jared Diamond’s excellent account of how human societies succeeded or failed based on the accidents of plant, animal and climate distributions. “Origins” is the story of life on earth told from the point of view of geology, plate tectonics and global climate. I was aware that the cradle of our species lay in the rift valley of Eastern Africa, but I didn’t connect “rift” with the movements of tectonic plates, let alone how that particular geology brought together just the right climate conditions at just the right time to drive our ancestors out of the forest and into the grassy plains. Similarly, I knew about the recent ice age and the peopling of the Americas by travel across the Bering land bridge, but I didn’t realize that horses and camels originated in the Americas and traveled the opposite direction into Eurasia before going extin...