Designed to introduce basic ecological relationships in a lake community, this investigation uses a Lake Erie food chain involving people and walleye as an example. The first activity is a board game in the form of a biomass pyramid; students begin with 1000 kilograms of algae and attempt to reach the "harvest" with at least a kilogram of walleye. In follow-up activities, the concepts of food web, ecological pyramid, and loss of energy between trophic levels are studied. The teacher's guide includes patterns for the game board, objectives, teaching suggestions, and a key to questions contained in the accompanying student workbook. (Author/WB)