The purpose of this qualitative case study was to examine the nature of a first-year elementary teacher's specialized practices and knowledge for giving priority to evidence in science teaching and to explore the possible sources from which this knowledge was generated. Data included three audiotaped interviews, six videotaped classroom observations, lesson plans, and samples of students' work. The findings of this study reveal that the teacher gave priority to evidence by frequently engaging students in collecting evidence through observations and investigations, recording and representing evidence, and using that evidence to construct explanations. The findings of this study also illustrate that critical experiences during preparation to teach and specific university coursework acted as sources through which the teacher's specialized knowledge for giving priority to evidence was generated.