This week, we’re learning about ecology and biodiversity, and the preservation of endangered (and even extinct) species. We’re joined by Eric Dinerstein, Lead Scientist and Vice President for Conservation Science at the World Wildlife Fund, to discuss his new book The Kingdom of Rarities, about the challenges involved in studying rare and exotic animals. And we speak to Stuart Pimm, Doris Duke Chair of Conservation Ecology at Duke University, about his arguments against plans to revive extinct species.