Date of Award
Doctor of Philosophy
Ecology, Evolution, and Organismal Biology
Ecology and Evolutionary Biology
Jeanne M. Serb
Phenotypic convergence is a fascinating evolutionary pattern. Many taxa evolve remarkable similarities, often due to similar selection pressures, which suggest that there may be a limited number of solutions to a particular ecological challenge. However, some phenotypes are only superficially similar. For example, convergent evolution may occur at one phenotypic level such as behavior, but other components (morphology) of the same phenotype exhibit divergence. In other words, the solutions might be the same, but how taxa approach the problem could be very different. This then suggests that there may be multiple phenotypic optima that can tackle similar ecological challenges.
In this dissertation, I investigate the evolutionary patterns of life habits and shell shapes in scallops and how these phenotypic traits contribute to biological diversity. I found many scallop species have converged in life habit, but only a few lineages converged in shell shape. Rather, shell shape variation tends to be greater in species with less specific life habit requirements. However, scallop species with the gliding life habit have lesser shell shape variation. Interestingly, gliding can be performed by two distinct shell shapes, indicating that only some components of shell shape are important for the life habit, and others are free to vary. This research indicates that there is likely greater diversity in form, despite phenotypic similarities in function.
Alejandrino, Alvin, "Convergent evolution of life habit and shell shape in scallops (Bivalvia: Pectinidae) with a description of a new genus" (2014). Graduate Theses and Dissertations. 14056.