History doesn’t supersede evolution, it merely complicates it. - David Rains Wallace

Like all evolutionary stories, it is really two—of how the land bridge evolved, and of how people discovered it. Evolution occurs in geological time but is perceived in historical time.

Central America aroused my curiosity after twenty years of an education that had seemed largely to dull it. I had been a mediocre student, partly because I was lazy, but also because my enthusiasms seldom followed the curriculum. Curiosity was encouraged in theory, but students were supposed to be curious about what the authorities wanted to teach. In Central America, there were no authorities, or none that I was supposed to consult. Trees had no labels or park rangers to identify them, and I suddenly wanted to know what they were.

Central America’s highest value as a natural phenomenon may be not in its diversity and adaptations, priceless as those are, but in its powerful demonstration of life’s sphericality. Life would have been fundamentally different if it had evolved on a limitless flat substrate instead of a limited, spherical one. It’s hard to imaging what it would have been like, but one possibility is that it never would have evolved beyond the first unicellular organisms. If they had been able to expand their populations ad infinitum, they might never have undergone the competitive pressures that led to natural selection and increasingly complex organization. Civilization has come to see the sphere’s limitations as an obstacle, but this is unimaginative, like being angry at the curved horizon because it hides objects more than a few dozen kilometers away.