"Human," a new series from BBC and NOVA l PBS, tells the tale of our ancient family tree, embracing the complex and dramatic sides of the story. It asks: Who were the different species of humans that lived on this planet before us? What must it have been like to be in their shoes? And how did we become the only ones left standing? Ella Al-Shamahi, a paleoanthropoligist and host of "Human," tells SciFri Host Flora Lichtman, "It really suited us to portray ourselves as this kind of pinnacle of hum