The Grimes Lecture Series: Pathways to Sustainability features Dr. David Orr, Tonight, February 16, 6pm, Pugh Hall Ocora.   Dr. Orr's talk, entitled Building Resilience in a Black Swan World, will address the two greatest challenges facing humanity in the 21st century - preserving a habitable planet and establishing a fair, prosperous, and durable global society.   He will explore the question, "What does leadership on these issues mean for students and faculty, the business world, citizens and public officials?"   Dr. David Orr is the Paul Sears Distinguished Professor of Environmental Studies and Politics and Special Assistant to the President of Oberlin College and a James Marsh Professor at the University of Vermont.