This research draws on developments in educational research where "learning progressions" are emerging as a strategy for synthesizing research on science learning and applying that research to policy and practice, and advances in the natural sciences, where "interdisciplinary research on coupled human and natural systems" has become increasingly important. It focuses on the human systems that supply all of our essential goods and services (i.e., food, water, transportation), which begin and end in the earth's natural systems. In order to investigate what students know about how human actions affect environmental systems, we developed assessments focusing on "supply and waste disposal chains". In addition, students were asked about a major environmental issue--global warming. Assessments were administered to elementary, middle, and high school students from rural, suburban, and urban schools. Results from this study provide insight into how student knowledge of connections between human-engineered and natural systems varies across grade level and context, which is essential if we are to teach students to be responsible citizens and stewards of our environment. (Contains 6 tables, 4 figures, and 6 notes.)