Meeting Abstract
The role of phenotypic plasticity in evolution has become increasingly apparent in recent years. A primary recent interest has involved the possibility that it could guide evolutionary transitions and influence patterns of adaptive diversification, including the evolution of phenotypic novelties. Here we offer evidence that not only does plasticity influence evolution in these ways, but that it also can produce apparent evolutionary pattern that may in represent plastic loss of ancestral phenotypic expression in novel environments due to the disappearance of a requisite environmental trigger. Under these circumstances lack of expression is the novelty in adaptive radiations, yet, as long as the phenotype is still responsive to the environmental trigger it can be expressed if the environment reverts to ancestral conditions, with the ancestral trait appearing as a novelty. We offer evidence that the capacity to express plastic traits can be retained for thousands of generations, although in some cases, modified in pattern of expression or intensity of the environmental trigger required for expression. Distinguishing lack of expression, or evolutionary loss requires examination of multiple taxa in a radiation to correctly infer novelties versus ancestral traits and to understand transitions in plasticity over time and the possible roles of plasticity in evolutionary change. Such analyses can provide novel insights into the role of plasticity in evolution, but is exceptionally difficult as it requires a clear phylogenetic understanding of the group, understanding of the ecology of the species or populations, and the capacity to evaluate patterns and underlying genomics of plasticity in multiple populations or species.
