Biological clock may refer to:
- Circadian rhythm, living organisms' adaptations to solar related rhythms
- Age and female fertility
Famous quotes containing the words biological and/or clock:
“Man’s biological weakness is the condition of human culture.”
—Erich Fromm (1900–1980)
“Whoever considers morality the main objective of human existence, seems to me like a person who defines the purpose of a clock as not going wrong. The first objective for a clock, is, however, that it does run; not going wrong is an additional regulative function. If not a watch’s greatest accomplishment were not going wrong, unwound watches might be the best.”
—Franz Grillparzer (1791–1872)