The five extinctions that have impacted the Earth over the past 400 million years—the Ordovician-Silurian, Late Devonian, Permian-Triassic, End Triassic, and Cretaceous-Tertiary—may be set to include another one on a massive scale. This alarming program assesses the extent to which Homo sapiens is provoking the planet’s sixth extinction. According to scientists, wholesale destruction of habitats by humans contributes to the disappearance of 27,000 species each year. With decimation proceeding at such a rate, how long can life on Earth survive? Interviews with Oxford University zoologist Richard Dawkins, Harvard biologist Andrew Knoll, and Sussex University paleontologist Richard Fortney are featured. (52 minutes)