Teaching a Stone to Talk: Expeditions and Encounters

by Annie Dillard

Geography is the key, the crucial accident of birth. A piece of protein could be a snail, a sea lion, or a systems analyst, but it had to start somewhere. This is not science; it is merely metaphor. And the landscape in which the protein “starts” shapes its end as surely as bowls shape water. We have all, as it were, blown back together like the finches, and it’s hard to imagine the isolation from parent species in which we evolved. The frail beginnings of great phyla are lost in the crushed histories of cells. Now we see the embellishments of random chromosomal mutations selected by natural selection and preserved in geographically isolate gene pools as faits accomplis, as the differentiated fringe of brittle knobs that is life as we know it. The process is still going on, but there is no turning back; it happened, in the cells. Geographical determination is not the cow-caught-in-a-crevice business I make it seem. I’m dealing in imagery, working toward a picture. Geography is life’s limiting factor. Speciation—life itself—is ultimately a matter of warm and cool currents, rich and bare soils, deserts and forests, fresh and salt waters, deltas and jungles and plains. Species arise in isolation. A plaster cast is as intricate as its mold; life is a gloss on geography. And if you dig your fists into the earth and crumble geography, you strike geology. Climate is the wind of the mineral earth’s rondure, tilt, and orbit modified by local geological conditions. The Pacific Ocean...