EAR-PF: Unraveling the Convergent Origins of Secondary Palates in Amniotes

Morris, Zachary, New Haven CT

Investigators

Abstract

Dr. Zachary S. Morris has been granted an NSF EAR postdoctoral fellowship to conduct research and outreach activities at Yale University under the mentorship of Dr. Bhart-Anjan S. Bhullar. Convergent evolution, or the independent derivation of similar features, as observed in the fossil record is arguably the greatest evidence of evolution by natural selection. However, how and why convergent evolution has happened is often poorly characterized. One striking, and understudied, example of convergent evolution is that of the secondary palate in amniotes (reptiles, mammals, and birds), which completely restructures the roof of the mouth and affects both feeding and breathing. This project will integrate analyses of the fossil record and developmental processes, to understand the timing and pattern of palate evolution and increase our understanding of the mechanisms driving the important phenomenon of convergent evolution. This project is an ideal platform for the mentorship of students, the development of classroom and public lectures, and outreach and education about the fossil record and developmental mechanisms of evolutionary change. Living amniotes and their extinct relatives in the fossil record display an astounding array of palate specializations, reflecting over 300 million years of evolutionary specialization in anatomy, diet, and behavior. Ancestrally the amniote palate allows the nasal passage to open into the mouth anteriorly, but mammals, crocodilians, and some lizards and turtles have independently derived an ossified secondary palate that segregates respiratory and olfactory functions from food acquisition and processing. This project will use quantitative analysis of the fossil record and modern evolutionary modeling with state-of-the-art imaging of embryonic anatomy in 3D to address two major research questions: 1) how has amniote palate shape evolved and secondary palate convergence been achieved? and 2) how has palate development changed to allow secondary palate convergence? By studying palate shape change at two distinct scales, macroevolutionary and developmental, the results of this project will reveal insights into the fundamental developmental and evolutionary mechanism that underlie the phenomenon of convergent evolution. Dr. Morris will develop educational materials for undergraduate and graduate students as well as public outreach activities through the Yale Peabody Museum. 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.