February Fourier Talks 2007

FFT Blues: Fourier analysis and the structural colors of biological tissues

The non-pigmentary colors of the tissues of living organisms are produced by the physical interaction of light with structures in the tissues. Contrary to what has been previously assumed for many decades, we have established now that many of the blue and green colors observed in the tissues of mammals, birds, and butterflies are the result of coherent scattering. Using Fourier analysis we have shown that the analyzed structurally colored tissues are quasi-ordered on the appropriate nano-scale to produce the observed colors by constructive interference. Understanding the mechanisms of coloration in animals is very important because of the role that bright colors play in communication, courtship display, and mate selection in many species. We will describe in this talk a fascinating manifestation of Fourier analysis and synthesis in nature providing a way to explain coloration phenomena which are of interest in behavioral and evolutionary biology.