The author investigated students' ideas about what defines an environment and how these ideas change across grade level and educational experience. A total of 81 students were sampled: 18 seventh graders, 20 eighth graders, and 24 ninth graders from general biology, and 19 ninth graders from college preparatory biology. The environments task was a two-part task. First, students drew a picture of an environment and explained their drawing. Next, students were shown a series of photographs and asked to indicate whether the photograph depicted an environment and to explain their response. In general, students understood an environment from a limited ecological perspective; that is, an environment is a location where animals live and or an area that supports animal life. An environment is a natural landscape; human-managed or built landscapes were not seen as environments by these students. For these students, humans do not appear to be apart of an environment but are separate from it.