This video is from "Evolutionary Foundations for Medicine and Public Health: Focus on Infection and Cancer", a course organized by Randolph Nesse that was offered from August 6-10, 2012 at the Mount Desert Island Biological Laboratory, Bar Harbor, Maine. Sponsors who made the course possible include the National Evolutionary Synthesis Center, The Dana Farber Cancer Institute, and The Evolution, Medicine, and Public Health Foundation. Editing of these videos was made possible Joon Yun, MD and the Palo Alto Institute. Information on future courses will be posted at The Evolution & Medicine Review.