Abstract
Have you ever woken up just before your alarm went off? It's as if your body is wired with an internal clock. Actually, scientists have discovered trillions of them! We live by the clock. Stop and think about all the clocks that make our lives tick, from the alarm clock that gets us up in the morning to the thermostat that warms our homes and the internal clocks that run our cell phones and computers. Every little gadget, device, and smart appliance, along with the car we drive, literally depends on internal clocks. Our 24/7 world-from work to pleasure-is governed by timekeepers. Now scientists are discovering that we're not the only ones run by clocks. The whole living world has built-in clocks to keep its systems on schedule, from humans and animals to plants and single cells. Even at the chromosome level, genes are turned off and on by sophisticated clocks.