This study describes the experiences of two preservice science teachers as they progress through their respective teacher education programs and uses critical race theory to examine the manner in which conceptions about race and its pedagogical implications change over time. Using a longitudinal case study method, participants' conceptual ecologies of race and pedagogy are mapped both before and after student teaching, and each case is analyzed for evidence of conceptual change in these areas. Findings show that conceptions about race and the pedagogical implications of race changed in ways that likely would have gone undetected in earlier studies because they did not result in wholesale changes in beliefs or teaching practice. This study suggests that the difficulty of fostering an understanding of structural racism and difference may often be underestimated, as revising one's model about race is mitigated strongly by learners' existing conceptual ecologies.