Professional development is an essential component to maintaining quality teaching in mathematics and science (Monk, 1994; Milken, 2000; Loucks-Horsley et al, 2003). University mathematics and science faculty have been subject to criticism regarding professional development and teaching practices (CSMEE, 2000; NRC, 1999; NSES, 1996). Undergraduate students in secondary pre-service Science, Technology, Engineering, and Mathematics (STEM) teacher training programs adopt the models that they have experienced as learners in the university setting (NRC, 1999). This qualitative case study followed a team of three research faculty, one lecturer, one master teacher, and two graduate teaching assistants who team taught an upper level inquiry- based science research methods science course in a STEM teacher preparation program in the College of Natural Sciences at a large public Midwestern research university. Course instructor dialogue between members was recorded, transcribed and triangulated with teaching sequences, course materials, and student interaction during two semesters. The study detailed how faculty members’ and graduate teaching assistants’ content knowledge, pedagogical content knowledge, attitudes and beliefs about teaching and learning were confronted, challenged, and transformed using interdependent disquisition via regular weekly meetings and team teaching practices. Examples of actual dialogue and meeting characteristics are presented compared and discussed against best practices in science education. Four themes emerged from the data: (1) students’ inquiries drive the conversation, (2) confrontations sort out what works from what doesn’t, (3) leadership seems to contribute to learning opportunities for the team and (4) humor indicates the divergent creative abilities of the members of the team and engaging in humorous episodes facilitates learning between team members. Students were directly connected to team members’ developmental processes. This analysis suggests that measurable professional development opportunities exist in team meetings for science faculty and graduate teaching assistants when team teaching inquiry based undergraduate science courses. / text