How does the passage of time affect the existence of life on Earth? Discover how soldier crabs have their own alarm clocks, how plants tell the time, and why humans live far longer than we should. Plus, see hummingbirds and horses evolve before your eyes. Speeding through millennia, computer-generated images and accelerated footage reveal how plants and animals manipulate time as they strive to find food, meet a mate and fulfil their ultimate purpose - creating the next generation.