The most ancient shark ancestors swam the Earth hundreds of millions of years ago. What lessons can be learned from studying how they fight off infection?Evolutionary immunologist Helen Dooley of the University of Maryland School of Medicine and the Institute for Marine and Environmental Technology explains how immune systems of humans and sharks are related and what might that mean for curing diseases.Then, biologist and forager Nick Spero of the Natural History Society of Maryland gives us a preview of Shark Fest and describes the allure fossilized shark teeth. Shark Fest is July 21st and the next visit to Stratford Cliffs is July 27th.