This paper characterizes in-class discussion of clicker questions among upper-level biology majors, demonstrating that students exchanged ideas in 75% of the recorded clicker discussions, using high-quality reasoning almost 50% of the time. In addition, when cued by the instructor to use reasoning, they engaged in higher-quality discussions.

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The diversity of tooth location in teleost fishes provides an excellent system for comparing genetic divergence between teeth in different species (phylogenetic homologs) with divergence between teeth within one species (iterative homologs). We have chosen to examine the expression of three members of the bone morphogenetic protein (Bmp) family because they are known to play multiple roles in tooth development and evolution in tetrapod vertebrates. We characterized expression of Bmp2a, Bmp2b, and Bmp4 during the development of oral and pharyngeal dentitions in three species of teleost fishes, the zebrafish (Danio rerio), Mexican tetra (Astyanax mexicanus), and Japanese medaka (Oryzias latipes). We found that expression in teleosts is generally highly conserved, with minor differences found among both iteratively homologous and phylogenetically homologous teeth. Expression of orthologous genes differs in several ways between the teeth of teleost fishes and those of the mouse, but between these vertebrate groups the summed expression pattern of Bmp genes is highly conserved. Significantly, the toothless oral region of the zebrafish lacks Bmp expression domains found in teleosts with oral teeth, implicating these genes in evolutionary tooth loss. We conclude that Bmp expression has been largely conserved in vertebrate tooth development over evolutionary time, and that loss of Bmp expression is correlated with region-specific loss of the dentition in a major group of fishes.

Recordings of introductory biology student discussions of clicker questions demonstrate that students use reasoning and questioning in their discussions and that their use of these discussion characteristics is heavily influenced by the cues they hear from learning assistants during discussions.

Cultivating institutional transformation has been of recent interest in education research. This theoretical paper presents six principles for supporting sustained change efforts at the department level. Considering change efforts at the level of "principles" is valuable because principles are grounded in theoretical and empirical knowledge, but are abstract enough to be adapted to many contexts. For each principle we argue for its value, drawing on previous literature in higher education, organizational change, discipline-based education research, and design thinking. We then give illustrative examples of how each principle was embodied within the Departmental Action Team (DAT) project. The DAT project facilitates the implementation of effective changes within university science, technology, engineering, and mathematics departments. We conclude with a discussion of how these principles can be applicable across a variety of institutional transformation efforts.

Bone morphogenetic protein (Bmp) signaling has been shown to play important roles in tooth development at virtually all stages from initiation to hard tissue formation. The specific ligands involved in these processes have not been directly tested by loss-of-function experiments, however. We used morpholino antisense oligonucleotides and mutant analysis in the zebrafish to reduce or eliminate the function of bmp2b and bmp4, two ligands known to be expressed in zebrafish teeth and whose mammalian orthologs are thought to play important roles in tooth development. Surprisingly, we found that elimination of function of these two genes singly and in combination did not prevent the formation of mature, attached teeth. The mostly likely explanation for this result is functional redundancy with other Bmp ligands, which may differ between the zebrafish and the mouse.

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This study explored how using in-class accountability affects the nature of students’ clicker question discussions. A higher proportion of discussions in the random call condition contained exchanges of reasoning and some forms of questioning compared with discussion in the volunteer call condition, thus suggesting positive impacts of random calling.