The Big Picture

Species across all kingdoms of life have evolved 24-hr biological clocks -- and I want to know why

Whereas a lot of traditional research on circadian (i.e., 24-hr) rhythms has focused on the properties of circadian clocks in constant environments, I am interested in the role circadian clocks play in fluctuating light-dark conditions that have presumably provided selective pressure for the evolution of biological timekeeping. How precise is the adaptation of circadian clocks to 24-hr light-dark cycles? What is the range of light-dark frequencies in which biological clocks can correctly anticipate these environmental transitions? In what circumstances do circadian timekeepers enhance reproductive fitness -- and why? Advised by Mike Rust and Aaron Dinner, I am addressing these issues experimentally and computationally in the photosynthetic cyanobacteria, the simplest known organisms with circadian clocks.