To differentiate: Exogenous and endogenous timing. Introduction: The most essential characteristics of plants as well as animals are synchronized with the environment’s 24-hour daytime-nighttime cycle. There are two different mechanisms through which synchronization is attained.

Difference between endogenous and exogenous timing.

• In exogenous timing, an animal is capable of synchronizing its rhythms of daytime-nighttime with the daytime-nighttime rhythms of the environment using exogenous (external) cues. In exogenous timing, the built-in clock of animals indicates the endogenous ability of animals to keep tracking the time. The endogenous clock of animals is synchronized with the environment’s daytime-nighttime cycle, which is similar to setting a watch.
• An example of exogenous timing is the sleep-wake cycle...