They compare the species' diversity in three areas on their school grounds. Students locate examples of species' diversity in their community. Cooperative groups build a structure from toothpicks to model stability. Cooperative groups make blocks from small milk cartons and together, as a class, they design a food pyramid. They participate in both a demonstration and a relay to show that energy is lost when it is transferred from producers to consumers.
Students list different ways that living things can depend on one another.
Students go outside and identify an organism's relationships to other living things. The class adds organisms to the ecosystem tube designed in Lesson 3 and describes how energy in the tube is passed from organism to organism. Groups draw a food chain, which includes organisms from their habitat bottles. Students design a bulletin board to show the interactions of a grassland ecosystem. They draw and construct several food chains and diagram ways organisms might interact within the ecosystem they designed in Lesson 3.