Ecology embraces the study of living plant and animal associations and their response to highly varied physical conditions found in a wide variety of ecosystems. The goal of paleoecology is to trace the evolutionary history of ancient ecosystems through geologic time. Each discipline offers a fascinating perspective on the other. Topics of discussion include: the role of biological and physical controls in the structure of communities; interpretation of fossil assemblages; meaning of biodiversity through a range of local to global scales; ecological succession in recent and ancient communities; and the role of mass extinctions in long-term community evolution. Ecosystems considered include marine-shelf benthos, reefs, rocky shores, rain forests, grasslands, and deep-sea hydrothermal vents. Readings are selected from current and recent journal articles in biology and geology. Following an initial group meeting, students will meet in pairs for tutorials. In addition, two lab sessions and a final group meeting are required. Participants in this course are eligible (but not obligated) to take part in a field trip to Baja California over Spring Break for the study of modern and ancient rocky-shore communities. Evaluation will be based on five written essays, five oral presentations, weekly participation in discussions, and participation in two scheduled lab sessions. Prerequisite: any 100-level Geosciences course (with preference for Geosciences 101) or consent of instructor. Enrollment limit: 10 (expected: 10).