NSF Postdoc Fellowship in Biology FY 2017: Exploring the evolutionary stability of larval type: a phylogenetic analysis of developmental patterns in extant and extinct sea biscuits

Armstrong Anne F, San Francisco CA

Investigators

Abstract

The fellowship supports research and training of the fellow that will utilize biological collections in innovative ways. This project will further our knowledge of how the diverse life cycles seen throughout organisms are generated and maintained. The echinoid echinoderms (sea urchins, sand dollars, and sea biscuits) display a wide variety of life cycles with some species producing offspring that leave their mother as juveniles, while other species produce offspring which spend over a year as a larva before developing into a juvenile. These developmental differences have important impacts on the connection and persistence of populations. This project will use biological collections to investigate how the life cycles of echinoderms have changed throughout the fossil record, how quickly developmental changes can arise, and how those life cycles affect broader biological patterns such as species ranges and rates of extinction. As part of this project, the fellow will partner with the education department at California Academy of Sciences to engage elementary school students. The fellow will add information about marine life cycles to classroom kits for local teachers to use in their schools. She will also participate in the Academy's distance learning program "Talk to a Scientist" which schools across the US can teleconference into. This project will contribute to undergraduate training, as the fellow will mentor REU students. Additionally this project will contribute to the digitization of museum archives. For this project, the fellow will create a phylogeny of the echinoderm genus Clypeaster (composed of the sea biscuits) using both genetic and morphological data. She will measure morphological features of extant and extinct species to determine the egg size and larval type of each species. By combining a phylogeny with these developmental data, the fellow will analyze how developmental patterns have evolved throughout the history of this group, how stable developmental type is, and how quickly changes in developmental type can arise. The genus Clypeaster provides an exceptional and rare opportunity to test many core Evo-Devo theories due to the extensive literature on the development of extant species, its remarkably complete fossil record, and the ability to determine developmental traits from fossilized adults. The phylogeny and morphological database created for this project will serve as a resource for other scientists. Results from the studies will be published in peer-reviewed journals and shared at scientific meetings.