FRIDAY, October 26, 2007
Time: 2:00 - 3:00 PM
Constant Hall 2100

Title: Hiding in the Light, the Color of Night, Cataracts, and Invisible Fish: The Relevance of Optics to Biology

Dr. Sonke Johnsen
Department of Biology
Duke University

Dramatic recent improvements in both optical instrumentation and computational power have now made it possible to apply optical physics to biological systems, despite their complexity. This talk explores three such investigations. The first examines counterillumination, which is the ability of many oceanic animals to hide their silhouettes from predators below them by lighting up their ventral surfaces. The second begins with the recent discovery of color vision in nocturnal animals, which leads to a study of the colors of the night sky and the justification for a sensory ability that can only reduce sensitivity. The final portion of the talk is a mathematical analysis of the ultrastructure of transparent and opaque tissues using fourier techniques and Debye scattering theory. Both human cataracts and the remarkable number of transparent ocean animals are explored.