The significance of island biotas



Island biotas have played a significant part in evolutionary biology, because they are so often starkly different from continental biotas (even though it took Darwin some time to realize this; his visit to the Galapagos Islands was not the converting experience often claimed for it). In recent years, most interest has concentrated on species diversity on islands, but differentiation of endemics is probably worth more attention. Key factors in the evolution of island forms include the complementary processes of Mayr's ‘genetic revolution’ (a genetic bottleneck, particularly when a previously empty area is colonized; and adaptation in isolation), the opportunistic (not perfecting) nature of natural selection, and the ecological history of island colonists.