We begin this encore broadcast on the theme of earth, air, fire, and water with a dive into pre-historic waters, where human evolution reaches far beyond the Neanderthal and ape. Last year, WBEZ’s Gabriel Spitzer spoke with University of Chicago paleontologist and anatomy professor Neil Shubin about his book, Your Inner Fish. Shubin says he’s always been fascinated by the mystery of how creatures made the leap from sea to land. And he told Gabriel that one key piece of the puzzle was understanding how human limbs and hands are constructed.