Lesson 6: Biological Clock and Timing in Animals

Exogenous Rhythm

a biological cycle controlled by external factors

Endogenous Rhythm

it’s an internally driven biological cycle regulated by the biological clock, operating without the need for an environmental stimulus.

Biorhythm

It’s the natural cycles that control changes in our body's functions and behaviors

Biological Clock

It’s an innate mechanism that controls an organism’s body functions on a daily, seasonal, or yearly cycle and is entrained by zeitgebers.

Free-running period

A cycle of behavior that continues without external cues, showing the natural rhythm of an organism.

Period of Rhythm

It’s the time it takes to complete a cycle of activity

Zeitgeber

It’s the environmental cue that rests the biological clock

Entrainment

the process of resetting the biological clock to match external cues

Phase shifting

it’s how much the activity/rhythm has shifted forward or back during entrainment

The period of Circadian Rhythm is

~24 hours

The period of Circatidal is

~12.4 hours

The period of Circalunar is

~29.5 days

The period of Semilunar is

~14.8 days

The period of Circannual is

~365.25 days