Abstract
How repeatable is evolution? Not so long ago, the answer to this question would have told us as much about the scientist as it does about evolution: surveying the broad brush of biodiversity, the naturalist sees parallelism everywhere. In the sky, there are flying birds, gliding mammals and even true flying mammals. In the sea, there are fishes, seals, whales and dolphins. Not so, says the molecular taxonomist: everywhere in the genome, the tick-tock of the molecular clock tells us that species are splitting away from each other. The convergence that the naturalists see everywhere, according to the molecular taxonomist, is nothing more than an evolutionary echo. Adaptations may be shaped by the hand of selection for sure. But mutations are, as we all know, random.
