Through the construction of arguments, students are invited to make sense of the concept of a species and its connection to both extinction and local biomes. Scientific argumentation is the process by which scientists engage in discourse aimed at developing common knowledge about the natural world (Driver et al. 1994). This article describes a 5E lesson that includes details for each stage of the inquiry-based experience as well as references to "A Framework for K-12 Science Education" and relevant Common Core State Standards in English language arts and mathematics. The objectives of this lesson were for students to learn about endangered species native to their region, to analyze and interpret empirical data (Scientific Practice #4, NRC 2012 pp.61-63), to construct an explanation asserting that the species they selected is the most important to the overall health of the ecosystem (Scientific Practice #6 NRC 2012, pp. 67-71), then to communicate their arguments to their peers (Scientific and Engineering Practices #s 7 and 8, NRC 2012, pp.71-77).