Science education has a central role to play in preparing a scientifically literate citizenry that is capable of understanding complex environmental challenges facing human societies and making well-informed and evidence-based decisions that help resolve these challenges. However, evidence suggests that most Americans are poorly equipped with the knowledge necessary for informed environmental action. In this study, we attempted to understand how the language of science textbooks works to represent the world for students in distinct ways that have serious implications for their ecological literacy. Using a methodological framework based on critical discourse analysis and systemic functional linguistics, we focused on clarifying the textual representations of the relationships between natural and social systems as portrayed in a seventh-grade science textbook that is widely adopted in middle schools in Georgia, United States. Results indicate that this science textbook offers outdated representations of natural systems' relationships with social systems and the role of human agency in these relationships. We discuss implications of these textual representations and call for reformed science textbooks that underscore the ecological embeddedness of the social world.