biological clock

views updated

biological clock Internal system in organisms that relates behaviour to natural rhythms. Functions, such as growth, feeding, or reproduction, coincide with certain external events, including day and night, tides, and seasons. These ‘clocks’ seem to be set by environmental conditions, but if organisms are isolated from these conditions, they still function according to the usual rhythm. If conditions change gradually, the organisms adjust their behaviour gradually.

More From encyclopedia.com