Meeting Abstract
Innovations in functional morphology, physiology and biochemistry are thought to be a major force in shaping evolutionary patterns, with the potential to drive adaptive radiation and influence the evolutionary prospects for lineages. But the evolutionary consequences of innovation are diverse and usually do not result in adaptive radiation. What factors shape the macroevolutionary impact of innovations and can we predict what kinds of innovation will lead to diversity as opposed to those that result only in greater specialization? I present a framework for studying biological innovations in an evolutionary context. Innovations are discrete changes in functional mechanisms that enhance organismal performance. But because of the ubiquity of trade-offs in functional systems, enhanced performance on one axis often occurs at the expense of performance on another axis, such that many innovations result in more of an exchange of performance capabilities, rather than an expansion. Innovations may open up new resources for exploitation and their macroevolutionary consequences depend heavily on the adaptive landscape around these novel resources. I survey 12 innovations in the feeding mechanism of labrid fishes, an exceptionally successful and trophically diverse group of reef fishes, and explore their consequences for performance, patterns of resource use, and macroevolution. All of the innovations provide performance enhancements and result in changes in patterns of prey use. But 11 of 12 are associated with ecological specialization and only one has promoted further ecological diversification. Because selection acts on the specific performance enhancement and not on the evolutionary potential of an innovation, those that enhance diversity are rare. Thus the macroevolutionary potential of innovations depends critically on the interaction between the performance enhancement and the ecological opportunity that is exposed.
