Recent reform documents and science education literature emphasize the importance of scientific argumentation as a discourse and practice of science that should be supported in school science learning. Much of this literature focuses on the structure of argument, whether for assessing the quality of argument or designing instructional scaffolds. This study challenges the narrowness of this research paradigm and argues for the necessity of examining students' argumentative practices as rooted in the complex, evolving system of the classroom. Employing a sociocultural-historical lens of activity theory (Engestrӧm, 1987, 1999), discourse analysis is employed to explore how a high school biology class continuously builds affordances and constraints for argumentation practices through interactions. The ways in which argumentation occurs, including the nature of teacher and student participation, are influenced by learning goals, classroom norms, teacher-student relationships and epistemological stances constructed through a class' interactive history. Based on such findings, science education should consider promoting classroom scientific argumentation as a long-term process, requiring supportive resources that develop through continuous classroom interactions. Moreover, in order to understand affordances that support disciplinary learning in classroom, we need to look beyond just disciplinary interactions. This work has implications for classroom research on argumentation and teacher education, specifically, the preparation of teachers for secondary science teaching.