Coral reef ecosystems are beautiful and vibrant underwater communities inhabited by a spectacularly diverse and abundant array of organisms essential to human needs. Reefs are severely threatened worldwide?estimates are that one-fifth of coral reefs have already been lost or severely damaged, and the rest are expected to disappear before the end of this century. The intrinsic value of coral reefs is incalculable and immense, and this technical note seeks to educate students about that value, as well as the threats?global and local?to coral reefs.