WHETHER IT EMERGED from a primeval soup of organic chemicals, left to simmer in some warm little pond, or it was boiled up in a deep-sea volcanic cauldron, it took only (in geological terms) a billion years for the simplest life to inhabit our infant planet. But then it rather dragged it heels (not that it had heels) and it took another 2.6billion years to evolve into anything more complex than a sponge.
By the time the planet was four billion years old, evolution had only progressed as far as creating some weird, immobile creatures that were still more plant than animal. Then, almost over night, evolution went nuts. In the space of just 20million years, between 540 and 520 million years ago, a multitude of creatures emerged that were not only advanced compared to what came before, but had actually set many of the standards around which life today is built.