Darwin's Paradox

Many different life forms occupying a vast array of ecological niches, inhabiting waters that are otherwise remarkably nutrient-poor. Coral reefs make up about one-tenth of one percent of the earth's surface, and yet roughly a quarter of the known species of marine life make their homes there.

The mystery of Darwin's Paradox ultimately revolves around the question of why a coral reef ecosystem should be so rich in variety while the surrounding waters of the ocean lack that same marvelous diversity. Similarly, big cities allow far more commercial exploration of the adjacent possible than towns or villages, allowing specialization in fields that would be unsustainable in smaller population centers.