16 - Convergent Evolution and Community Convergence: Research Potential Using Intertidal Fishes

Abstract

The chapter describes how intertidal fish faunas offer compelling and unexploited opportunities for the study of convergent evolution and community convergence. The only way that such studies can be properly conducted, however, is through phytogenetic analyses based on well-resolved phylogenies of the intertidal species and their closest relatives from other habitats. The chapter further explains how the structural and functional traits that could serve as the basis for an analysis of convergent evolution are identified, and elements that should be part of an appropriate research design. The importance of such a research program is that demonstration of convergent evolution can address how fishes may or may not evolve, through adaptation, to increase their fitness in the intertidal environment. Rocky shores supporting intertidal fish communities are commonly separated by stretches of sandy beaches, by latitudinal temperature gradients, or by ocean basins. Varying degrees of genetic isolation have been found in fish species, including intertidal forms along coastlines and between mainland and island populations, indicating different amounts of gene flow between populations. Intertidal fish communities are, therefore, isolated to varying degrees from one another and undergo development and evolution in some degree of isolation depending on the amount of gene flow among them.