Biology teachers’ personal and enacted pedagogical content knowledge of evolution (PCK EVO ): is classroom practice enough for PCK development?

An exploratory study of teachers’ pedagogical content knowledge (PCK) of evolution, drawing on the Magnusson et al. (1999) and Vergara et al. (2015) models, is presented. To capture PCK of two Chilean female biology teachers, a Content Representation (CoRe) interview was conducted before and after they taught the evolution unit in Grade 9. All lessons in the unit were video recorded and analysed using the PCK rubric. Based on these recordings, specific situations were selected, and video-based reflection provides opportunities for teachers to make their knowledge explicit. All interviews were analysed through qualitative content analysis, using the components of PCK as pre-existing categories. In terms of personal PCK, both teachers recognise the importance of genetics for understanding evolution and the persistence of preconceptions related to evolution by need in students. Regarding enacted PCK, the teacher with lower initial PCK exhibits more pronounced development, whereas the teacher with higher initial PCK experiences a more constrained progression throughout the unit. Reflecting on practice within a structured accompaniment process facilitated the mobilisation of specific PCK’ components; however, this did not lead to uniform effects on the development of their PCK.