The course will analyze the biotic and abiotic factors that influence or limit distributions of organisms. Emphasis will be placed on population and community biology, including evolution, genetics, behavior, models of population growth, species interactions and community structure. Metabolic and energy relationships at the ecosystem level also will be explored. Examples will be drawn from all domains and kingdoms of organisms. Students will be required to evaluate the role of a specific "keystone" species in an ecosystem and how the loss of that species impacts biodiversity in the ecosystem.