Erwin Bünning (23 January 1906-4 October 1990)
Erwin Bünning is known throughout the biological world as the person who discovered the endogenous daily rhythms known today as circadian rhythms. He first studied the daily up and down movements of the leaves of certain plants such as beans. The period of such rhythmic movement under normal conditions is twenty-four hours. Under constant environmental conditions, however, the period is not necessarily precisely twenty-four hours, but only approximately so. The endogenous rhythms are therefore known as circadian. This was all experimentally established in Frankfurt by Erwin Bunning as a twenty-three-year-old postdoctoral fellow who had just completed his doctoral work at the University of Berlin. The work was published in 1930. This subject became Bünning's principal line of research. However, it took almost thirty years more before the existence of such endogenous rhythms was generally acknowledged.
© 1994 American Philosophical Society.