Circadian rhythms and biological clocks

This chapter addresses questions about how rhythms in animal behaviors and physiological activities are generated. It first looks at some of the major behavioral characteristics of rhythmic patterns occurring daily and finds out how the observations made during these studies have led to the concept of biological clocks. The discussion touches on the discipline of chronobiology, which examines biological rhythm. The chapter also explores the molecular structure of these clocks and discusses how the individual clock components integrate to produce an oscillatory output. Lastly, the chapter summarizes what is known about the localization of biological clocks at a systems level.