The recent advances in biosensor design, wireless communication and computer architecture have enabled the realization of integrated, miniature wireless biosensors. Based on these technologies, the concept of Body Sensor Network (BSN) has recently been proposed to provide intelligent, context aware sensing. The BSN outlines the basic infrastructure for pervasive sensing. In addition to healthcare applications, it also has important value for life science research and enables large-scale, continuous monitoring of drug response and epidemic studies. This paper introduces the basic concept of BSN, outlines its major components and highlights several key applications for life science research.