| Increasingly, graduate teaching assistants (TAs) are relied upon to teach introductory undergraduate biology courses at many large universities. This change in the role of the TA in the 1980s prompted the development of professional development programs for science, technology, engineering and mathematics (STEM) TAs. However, many of these programs, workshops and courses do not consider the TA in their dual role as learner and teacher, nor are they based on theories of how people learn. In addition, to date, there are little data published that document TAs changes in behavior in response to TA professional development.;This dissertation is the first comprehensive research on biology TAs teaching introductory biology (Bio1) at a large university with very high research activity. This dissertation begins with research on Bio1 TAs, specifically, what do Bio1 TAs believe about effective teaching and student learning? Data from surveys of 30 Bio1 TAs revealed that they held beliefs about how teachers teach that opposed their beliefs about how students learn. These data, along with data collected through surveys about the effectiveness of their current professional development (i.e., traditional) influenced how we reformed TA professional development.;Second, this dissertation describes a novel model of TA professional development (i.e., reformed) based on how people learn and data on Bio1 TAs (see Appendix A). Third, this dissertation evaluates the reformed model of TA professional development using data from surveys, TA-designed learning objectives and assessments, and TA classroom practice. Together, these data provided support for the efficacy of this model of biology TA professional development. Reformed professional development statistically significantly improved the cognitive processing levels TAs asked their students to achieve via learning objectives and assessments, and improved the degree of learner-centered instructional practices occurring in Bio1. TAs' classrooms.;Finally, results from a case study of one TAs who was prepared to teach under both traditional and reformed models of professional development indicated that the expectations of the TA professional development program play a key role in determining the instructional practices of a TA, more so than his own beliefs.;This research presents the First reported data on biology TAs exploring the relationship among TA beliefs, professional development and practice. In addition, it also provides the only data on evaluation of biology TA professional development that is not self-report. The results from this research indicated the importance of critically examining and changing TA professional development as faculty work to reform undergraduate biology courses. |
