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Cichlid fishes (Perciformes: Teleostei) found in the lakes of Africa have served as model systems for the study of evolution. The enormous number of species (1000 in Lake Malawi alone), the great diversity of trophic adaptations and behaviors, and the extreme rapidity of their divergence (<50,000 y for some faunas) single out these organisms as examples of evolution in progress. Because these fishes are confined to discrete lacustrine environments and their origination is bounded by geological features, these groups provide models with which to study evolution. We review theoretical studies and empirical research on the cichlid faunas of Africa to provide a synthetic overview of current knowledge of the evolutionary processes at work in this group. This view provides the critical information needed to formulate and test hypotheses that may permit discrimination among the diverse theories and models that have been advanced to explain the evolution of these fishes. [ABSTRACT FROM AUTHOR]

Discusses the importance of ecology in the formation of species. How Charles Darwin got his ideas of species; Ecology being neglected in this century's evolutionary science; The ecological speciation model; Attention being given to environmental factors as well as genes; Bursts of speciation as seen in the cichlid fish in Africa's Lake Victoria; Study on marine and stream-dwelling stickleback fish from British Columbia and their genetically distant counterparts in Japan.