Exciting hands-on investigation focuses on the abundance and diversity of organisms (particularly macroinvertebrates) associated with accumulations of decomposing leaves in freshwater ecosystems. Students collect fallen leaves and create their own leaf packs, then design and conduct scientific, field-oriented experiments to determine the optimum conditions for biodiversity. Activities are adaptable to varying time constraints and class sizes. Kit includes all necessary materials for 6 groups of students to conduct leaf pack studies, tree identification manual, macroinvertebrate identification cards, strainer, petri dishes, sample trays, thermometers, hand lenses, and instructor's manual. All components are reusable.