There's no debating evolution, but a debate remains among biologists over how it actually works. Is evolution deterministic in that its outcomes could not have been otherwise, or is it more random? Harvard biologist Jonathan Losos defends the view that evolution is not deterministic, that takes many different pathways to endpoints that are historically contingent. Take for instance the island of New Zealand which has been geographically isolated from Australia for 80 million years. If evolution were deterministic, we'd expect to see dinosaurs just as they had once existed on Earth, but we see kiwis and moas instead. Losos says that has important implications for life may look like on alien worlds, i.e. don't expect any spacefaring T. rexes. Learn more about evolution from his book, Improbable Destinies: Fate, Chance, and the Future of Evolution.