The purpose of this study was to investigate how assessment instruments could be used in the college biology classroom for purposes other than researching instructional strategies (as they have been used in the past). Through participatory action research, a science educator and a biology faculty member examined how the CINS (Concept Inventory of Natural Selection) could be incorporated into the biology faculty member's classroom instruction. This paper shows that biology faculty members can use assessment instruments to build in-class activities and labs, to formatively assess student knowledge, and to confront student misconceptions. Several recommendations for incorporating assessment instruments in biology instruction and assessment are provided.