LIFE Birds do it.
Bees do it .
Alligators and petunias, fruit flies and polar bears do it. The baby in the womb does it. A teenager with pink hair, a 100-year old woman blowing out her birthday candles, and an Olympian carrying the torch all do it. So do you and I. Every living thing that's bigger than one cell does it. Every organism operates through the same mechanism of signal and response that has changed very little over the last 400-500 million years or so.