On its 50th anniversary, the landmark theory of island biogeography—the study of the distribution of species on islands over time—expands from land to sea with fascinating results. A team of researchers led by Dr. Hudson Pinheiro, postdoctoral ichthyologist at the California Academy of Sciences, have proposed a new conceptual model of island biogeography for marine organisms—a theory that explores how different processes (like sea level fluctuations and geographic isolation) influence marine species diversity around islands. The team found that, despite some similarities, the forces that tend to shape diversification and community assemblage on land are different from those that impact islands’ marine environments. Results—authored by researchers from the Academy, University of California, Santa Cruz, and Universidade Federal do Espírito Santo—are published today in Nature.