Discipline: Ecology Environmental and Earth Sciences
Subcategory: Geosciences and Earth Sciences
Room: Park Tower 8212
Jared Richards - UNC-Chapel Hill
Co-Author(s): Sara Kahanamoku, UC Berkeley Department of Integrative Biology, Berkeley; Seth Finnegan, UC Berkeley Department of Integrative Biology, Berkeley
The foraminifera Bolivia argentea (a unicellular protist with a calcite shell), can reproduce both sexually and asexually. The morphology of the shell indicates the reproductive mode: individuals formed from asexual reproduction have a large first chamber (megalospheric) while individuals formed from sexual reproduction have a small first chamber (microspheric). This system thus allows for inference of life history trends across multiple generations based only on shell morphology. Evolutionary theory suggests that the benefits of sexual reproduction outweigh that of asexual reproduction in variable environments while the opposite holds true in environmentally stable conditions. The Santa Barbara Basin (SBB), located off of the coast of central California, has high-resolution sediment records which serve as an archive of regional climate and ecology. The SBB thus offers a unique opportunity to examine life history variation at timescales much longer than those covered by laboratory and field studies of living populations. We quantified morphological trends in SBB B. argentea over the last two thousand years to explore how environmental changes may have affected the population?s trajectory over decadal to centennial timescales. We found that the proportionality of morphotypes present in the population varies greatly over time with no significant temporal trajectory. Finally, there appears to be a positive correlation between population density and the proportion of megalospheric individuals present in the prehistoric SBB ecosystem, corroborating evolutionary theory suggesting that any population will proliferate in stable conditions. We plan to further investigate this system to uncover more about the effects of ecological change on evolutionary trajectory.
Funder Acknowledgement(s): NSF UC Berkeley REU; Seth Finnegan Marine Paleoecology Lab
Faculty Advisor: Seth Finnegan, email@example.com
Role: I did all of the research, including the data collection and analysis, that I am presenting.