This session explores the cultural foundations of children's knowledge of the living world. Cognitive research on students' conceptual understandings has overly relied upon sequestered tasks and structured interviews; we argue that participant observation can provide insight into important particulars of everyday life to answer fundamental questions about the nature of children's learning of biology. These papers report on studies of the everyday cultural and social contexts in which children's informal ideas about the living world develop and are applied. The research employs a learner-centered focus and a cognitive ethnographic approach to explore children's knowledge as they utilize it in their homes, at school, and in an interactive science center. Research focuses on personally consequential biology topics including health, nutrition, and ecology. The papers report on the cultural experiences that shape children's biological knowledge and decision-making, similarities and differences between cultural groups, and implications for coordinating home and school experiences.