Biological clock may refer to:
- Circadian rhythm, living organisms' adaptations to solar related rhythms
- Age and female fertility
Famous quotes containing the word biological:
“It is not the literal past that rules us, save, possibly, in a biological sense. It is images of the past.... Each new historical era mirrors itself in the picture and active mythology of its past or of a past borrowed from other cultures. It tests its sense of identity, of regress or new achievement against that past.”
—George Steiner (b. 1929)