Even Darwin couldn’t really explain the massive explosion of evolution during the Cambrian Period some 540 to 520 million years ago. This evolutionary “big bang” which saw the abrupt appearance of dozens of animal groups, seemed inconsistent with Darwin’s theory of gradual changes over time. Scientists at the University of Adelaide in Australia looked atarthropods and, with the help of the fossil record and molecular dating methods, found that evolutionary rates in the Cambrian period were four to five times faster than today. But how could this be? They believe that game-changing innovations like predation, vision, and active swimming allowed species to evolve at a much faster rate, which supports Darwin’s theory. They said you see the same kind of thing when animals colonize new environments, like islands.