This is one of 25 assessment probes from the book,” Uncovering Student Ideas in Life Science, Volume 1: 25 New Formative Assessment Probes”, by Page Keeley and co-authors. All assessment probes in this collection are aligned to a particular science concept and field-tested by several teachers in classes of diverse student backgrounds. The purpose of this assessment probe is to elicit students’ ideas about the role of plants in a terrestrial ecosystem. The probe is designed to determine if students recognize that all animals depend on plants, whether or not they eat plants. The resource can be used to engage students in the topic or to assess their understanding along the way. The probe can be used as a class discussion starter.