Weston Observatory presents Zygmunt Jan Broël Plater speaking on "A Little Fish in a Pork Barrel: The Snail Darter Endangered Species Controversy, Environmental Law, and a Parable of Modern Societal Governance" from 7 to 9 p.m. at 381 Concord Road, Weston. Plater is a professor of law at Boston College Law School. Reservations required due to limited seating. Light refreshments will be provided. Call 617-552-8300.