From The National Geographic:
Fleet-footed animals, such as gazelles and cheetahs, aren’t the only livings things that rely on speed for their survival. The same is true for some plants and fungi. Consider the Venus flytrap, the poster child for carnivorous plants: Its jaw-like leaves can ensnare insects in an eye-blurring one-tenth of a second. Other plants employ similar lightning-quick movements, if not to hunt, than to spread their seeds, squirt pollen, or shake off predators. Plants don’t have muscles. So how can some plants move so quickly?
Using the laws of physics, two scientists have detailed the mechanical design principles that govern these speedy plant moves. “To understand biology, it is always useful to come up with general principles as we have in this case,” said Lakshminarayanan Mahadevan, a professor of applied mathematics and mechanics at Harvard University in Cambridge, Massachusetts. Mahadevan and his student, Jan Skotheim, report their findings in tomorrow’s issue of the research journal Science.