Since most parts of organisms perform multiple functions, to understand how conflicting functional demands can affect those parts, evolution is critical; however, neither a theoretical framework nor extensive real-world data are available to address this topic. To address this gap, this study will integrate detailed anatomical and engineering analyses (including computer modeling and real-world validation using models) of the shells of all 300 living species of turtle. Three functional attributes will be considered: shell strength, shell drag during swimming, and shell stability when the turtle is overturned. The data will be used to address three questions. Do shells that must perform more functions evolve differently than those with fewer functions (e.g., do aquatic turtle shells evolve differently than those of land turtles, which don't need to be efficient underwater?). Are there shells that perform poorly for any of their functions? If different functions impose different requirements on shells (e.g., flat shells seem best for swimming, but worse for strength), how do shells compromise among functions during evolution?
This study will address several recent Grand Challenges in Organismal Biology, helping scientists to understand how organisms interact with their environment during evolution and integrating the analysis of biological structures with advanced engineering techniques. All data will be made publicly available via the Dryad (www.datadryad.org) and Biomesh (www.biomesh.org) databases. The results will be applicable to other biological shells (e.g., eggs or skulls) or to the development of artificial structures such as small submersibles. This project has an extensive educational component. Twenty to twenty-five undergraduate students will work on this project, receiving applied training in cutting-edge imaging and analysis techniques (skills applicable in careers from medicine to engineering) and experience with scientific research. Students will also develop public communication skills when they help develop and present biology lessons with the PI at local primary schools.
