Stations-ID: L002 Instructions: Build a tower using local species! How many blocks can you remove before the tower collapses? Pulling the wrong rivet! The so-called “Rivet Hypothesis” compares the species in an ecosystem to the rivets in an airplane. Removing one of them probably won’t cause the plane to crash, since there are usually more rivets installed than are absolutely necessary. The same is true, at first, for living organisms in an ecosystem. If one species of wild bee goes extinct, there is likely another species that will continue to pollinate plants and serve as a food source for insectivores. The Rivet Hypothesis states, however, that this safety net has its limits! The more species that go extinct in an ecosystem, the more likely it is that the ecosystem will cease to function and ultimately collapse. Worse still: many systems haven’t been studied well enough for us to know which species are critical to their survival. If we accept that species go extinct because they can no longer find a habitat or are destroyed by pesticides, for example, then we are gambling every time with the possibility that they were the critical rivet whose loss causes the ecosystem to collapse! An Interconnected System An ecosystem is a delicate and fragile system. The living organisms in an ecosystem depend on one another in many ways! Every species has its own role, and only by working together can the cycles that form the basis of life—including for us humans—be sustained!