Maria Anderson | Feb 15, 2004 | 2 min read
What are circadian rhythms?These timing systems dictate when plants will bloom, force people to fall asleep at their desks, urge birds to fly south, and influence a host of other activities. While circadian rhythms run on a 24-hour clock, others also exist, including tidal, lunar, and annual rhythms.Which organisms have them?A lot; from bread molds to humans. Well-studied rhythms include those in cyanobacteria, the bread mold Neurospora crassa, rice, Arabidopsis, fruit flies, mice, Syrian hamste