This activity is designed to accompany an interactive on the Annenberg Learner website. Students investigate the changes that take place in an ecosystem when they alter the organisms in a food web. As they work with the simulation, they record their observations and data on this downloadable Google document and analyze their results. They then design their own experiment with the simulation, test it, and analyze it. Finally, they pose questions, make predictions, test them, and draw conclusions about animals in the real world.