An Introduction to Chronobiology


1. To describe how and why the physical environment varies rhythmically and how the biology of organisms is programmed to match that predictable variation.
2. To explain why chronobiologists – scientists who study biological timing – propose the existence of endogenous circadian clocks as biological mechanisms that control the daily activities of many organisms.
3. To make clear what is meant by a circadian clock.
4. To provide an introduction to these topics that is accessible for an undergraduate, or for a broader lay audience, but which also provides grounding in the rigorous methods of data collection in chronobiology.

We created this overview because few resources are available which meet condition (4).


Our basic overview is split into three different Parts. Links at the top and bottom of each page let you easily access each part, as well as a glossary of keywords.

In the main text, keywords look like this example. We emphasize them to underscore their importance as you familiarize yourself with the vocabulary of circadian biology. If you need a reminder about the meaning of a keyword, hover your cursor over them, and a short definition should pop up. Depending on your device, some keywords may appear clipped at times. To see the full definition, you can also click directly on the keyword to go to its entry in the Glossary. (You may want to keep the Glossary open in a separate tab as you read through each Part). 


We are always looking for ways to improve this resource, and welcome all your feedback about how the overview is working for you, suggestions for revision or expansion, etc. Beneath the navigation list on each Part of the overview, you’ll see a link to provide feedback. Click it at any time to provide anonymous feedback via a Google Form.


This basic overview was produced through collaborative work by members of the BioClock Studio. Acknowledgments and thanks are due as follows:

  • Planning, structuring, and drafting of the review (BioClock Studio 2015)
    • Kathleen Kao
    • Jonathan Loi
    • Hailey Sanden
  • Revisions and implementation of final web version:
    • Dr. Susan Golden
    • Dr. Michael Gorman
    • Dr. Ben Sheredos
  • Keyword definitions, and locating and creating graphics for figures (Bioclock Studio 2016) 
    • Jared Kim
    • Jenny Lee
    • Victoriah Nudell
    • Lucy Wu
BioClock Studio W2015 Intro to Chronobio Team: Ben Sheredos (mentor), Jonathan Loi, Kathleen Kao, and Hailey Sanden.
BioClock Studio W2016 Intro to Chronobio Team: Ben Sheredos (mentor), Victoriah Nudell, Jared Kim, and Jenny Lee.

Click to copy citation: Kao, K., Loi, J., Sanden, H., Kim, J., Lee, J., Nudell, V., Wu, L., Golden, S.S., Gorman, M., & Sheredos, B. (2016, September 22). Introduction to chronobiology. Retrieved from