This is an updated version of an existing lab. It includes some theoretical background information and the online lab which models Connell's 1961 classic competition experiment. Students can explore the fundamental and realized niches of two species of barnacles, Chthamalus and Balanus. One species can grow at a wider range in depth but can be outcompeted, while the other species is limited to deeper rock. Students can also cause sea level to change simulating global warming.