In this simulation, the user can study the competitive exclusion principle. The population of two species with a shared food source can be studied in a simple ecosystem individually and together. Click the "Introduction" button to read more information about the scenario, then set the variables and click "Run Simulation" to start. The accompanying worksheet options (and Google doc versions) walk students through a data collection procedure and include follow up questions about the competitive exclusion principle in a lab setting and in ecosystems. Check out the blog for more discussion of this simulation and the competitive exclusion principle.