A common assumption in the educational literature is that novice teachers can learn and develop over the course of their career. Yet there remain questions about this process: Do teachers continually refine their ideas in a linear fashion or are they selective -- filtering assorted influences from across their experience to address specific aspects of teaching? As educators grow and develop, there is an opportunity to investigate how teachers perceive the various instructional influences they encounter during their career, and, ultimately, how they make sense of the different perspectives. While there may be universal insights for teacher learning, this work focuses exclusively on science teachers, who, with the turn towards competency-based standards, must balance influences on both teaching content and the doing of science. Further, science instruction is sometimes deprioritized in an era of high-stakes Mathematics and English/Language Arts testing, which can result in normative pressures antagonistic to more ambitious science teaching. The three studies in this dissertation, therefore, add to both our ecological understanding of what teachers perceive as impacting their practice, and how they connect learnings across time and place. Taken together, these findings have important implications for pre-and in-service teacher learning. The first article builds upon and extends the notion of the "two-worlds pitfall" (Feiman-Nemser & Buchman, 1985) by exploring two questions with graduates of a single teacher education program. First, the study investigates what beginning secondary science teachers report as learning from their teacher education program. Using interviews and a rank order task, the findings indicated that all of the teachers attribute at least some of their instructional practices to teacher education; however, there was considerable variation. Moreover, of the attributed practices, there was a range of both science-specific and content-agnostic practices. Second, the study highlighted that teachers learn from a wide range of influences, including but not limited to, teacher education. On average, teachers reported that actual teaching experience was the most impactful influence on their classroom practice, above their own experiences in classrooms as students, above teacher education, and above their specific school context. Collectively, the findings raise questions about how to design teacher education to account for the variety of instructional influences, for what aspects of science teaching candidates are expected to develop in teacher education, and for how to emphasize experiential learning opportunities. Whereas the first paper focuses on teacher education, the second paper considers the other half of the "two-worlds pitfall" (Feiman-Nemser & Buchman, 1985) -- the educative nature of teachers' school context. A persistent perspective in education is that teachers enjoy tremendous autonomy over their classroom, yet more recent literature has challenged this notion. Drawing upon organizational theory, this exploratory study uses drawn mental models, instructional artifacts, and interview data from mid-career secondary science teachers to explore teachers' perceptions of the influence of their school context. Findings imply that teachers were keenly aware of the educative nature of their specific circumstances. However, the influence was not uniform; the teachers indicated that some aspects of their teaching -- those areas more aligned with curriculum and instruction, were more likely to be influenced by their school context compared to others. Additionally, results from this study signal that teachers perceived school influence largely through normative processes -- that is, the established expectations, training, and colleagues. The findings suggest that we need to further explore how ideas, strategies, and practices from teacher education and professional development are presented to account for the educative influence of teachers' specific school contexts. As teachers grow into the profession, they encounter a wide array of ideas about what constitutes "good" science teaching, and therefore must make decisions about their instruction to best support students' success. Whereas the first two studies in this dissertation focus on the influence of teacher education and one's school context, respectively, the third paper considers all relevant instructional influences to investigate how teachers foreground some ideas about teaching and background others. Extending a theory of teacher learning with the same sample as the second study, this paper argues that teachers differentially take up ideas about science teaching. Across a wide-variety of perceived instructional influences, some teachers privileged broader pedagogical frameworks, while others placed more weight on their specific contexts. Additionally, the results illustrate that common frameworks for professional development are only partially aligned with what mid-career science teachers perceive as important for changing their practice. The data from this work suggests that pre- and in-service learning opportunities need to account for how teachers' differentially weight instructional influences, while providing examples, opportunities for practice, and sufficient resources. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. 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