Dr. Colby Clark will present "Topographical Constraints and Ecological Units: Where Does an Ecosystem Start and End?" as part of the WSU Philosophy Department's Colloquium series on Wednesday, Dec. 3, from 3:30pm – 5:00pm in McKinley 207. A major concern in the philosophy of ecology is the ecological unit question. The ecological unit question asks: how should the boundaries of an ecological unit be defined? Three views exist that offer metaphysical, epistemological, and geographical responses to the ecological unit question. In this presentation, a novel interpretation of the ecological unit question is proposed that contextualizes ecological units within a field of topographical constraints (i.e., physical features in the landscape that filter dispersal processes). The thesis is that topographical constraints are causal in nature.