Tide pools are habitats for several kinds of organisms that attach to the rocky surface and depend upon tides for food and oxygen. Sea stars present in these tide pools feed on mussels and other shellfish that have no other natural predators. How will it most likely impact species diversity if all of the sea stars are removed from the tide pool ecosystem?

The questions have been asked in several important state and regional science exams in the United States. For example: TAKS-Texas Assessment of Knowledge and Skills, New York State Educational Department Regents exams, California Standards Test, etc.