Mark Plotkin: What the people of the Amazon know that you don't

"The greatest and most endangered species in the Amazon rainforest is not the jaguar or the harpy eagle," says Mark Plotkin, "It's the isolated and uncontacted tribes." In an energetic and sobering talk, the ethnobotanist brings us into the world of the forest's indigenous tribes and the incredible medicinal plants that their shamans use to heal. He outlines the challenges and perils that are endangering them — and their wisdom — and urges us to protect this irreplaceable repository of knowledge.