The diversity of life on earth (Biodiversity) represents a resource of unknown potential for improving human welfare that is increasingly put at risk by human activities. Perhaps the most significant challenge of the 21st century is to resolve how to best utilize this resource while providing effective stewardship such that biodiversity resources are maintained for future generations. Meeting this challenge requires a detailed understanding of the processes that promote, maintain, and diminish biodiversity at all levels of biological organization, from molecules to ecosystems, a theme that unites the many subdisciplines within biology. Organisms are intimately connected to their environments and environments vary on multiple spatial and temporal scales. Hence, utilization and stewardship of biodiversity requires understanding its connection to both natural and human-induced environmental change. This emphasis is offered for the B.S. only.