Evolution depends on the possible outcomes of developmental processes, yet scientists lack a formal mathematical structure to incorporate developmental biases into evolutionary theory. One challenge in developing a general modeling framework is that developmental biases are unique to the structure and species in question. This research will incorporate models of cartilage and bone growth into an evolutionary framework. The researchers will build on recent comparisons of ear structures among toads; many toad species have impaired ear development and lack structures commonly important for hearing. The project will bring together researchers and students with mechanical engineers to create a mathematical model that predicts ear structures based on developmental parameters. The model will examine evolutionary changes that can switch whether or not toad species develop ears. This framework will form a general foundation that can be applied to other structures to understand how developmental processes limit possible outcomes of mutations. The increased collaboration between engineers and biologists will provide key educational opportunities for all participants. The project includes developing courses and activities that will help undergraduates, graduate students, and professors learn evolutionary modeling methods.

To accomplish these goals, the PI has recruited three mentors to model the effects of developmental biases on morphological diversity: an engineer who models biological processes, a leading evolutionary developmental biologist who studies neural crest and cartilage development in amphibians, and an expert in phylogenetically based models of evolution. The scientist and the engineer will work together in cross-disciplinary courses to gain complementary expertise and train CSU students. They will adapt models of cartilage growth to explore the extent to which cell size, density, and local chemical environments influence ear development and also which cell-cell or cell-environment interactions could alter morphology. These models will generate testable predictions that will guide experiments in collaboration with the evolutionary developmental biologist and will be incorporated into an explicit evolutionary framework under the guidance of the phylogenetic modeler. In addition to the educational opportunities for the PI and graduate students, another outcome of this work will be a publicly available module to better teach evolutionary biology in large introductory biology classes.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

National Science Foundation (NSF)
Division of Environmental Biology (DEB)
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Samuel Scheiner
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Colorado State University-Fort Collins
Fort Collins
United States
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