- Plant defences
- Animals and plants also live by circadian rhythms. These are almost 24-hour cycles.
- This process helps plants to flower and reproduce, germinate, grow roots and shoots, and drop their leaves at the appropriate time.
- Many plants detect and respond to changes in the length of daylight to control their growth and reproduction.
- This is called ‘photoperiodicity’
- Plants use these cycles to close their flowers at night and rotate their leaves towards the Sun during the day.
- Animals, including humans, use circadian rhythms to regulate sleeping and feeding patterns, as well as hibernation and migration (eg the Eastern North American monarch butterfly). Jet lag is the result of circadian rhythm disruption.