Current Research in EEPS Seminar: Dr. Lydia Tackett – North Dakota State University
Using biosediments to track paleoecological trends in deep time
Predator-prey interactions in the fossil record are nebulous and difficult to identify, but increased predation is theorized to induce changes in prey taxa through a process called escalation. However, morphological changes can have many causes, including abiotic factors such as changes in depositional environment, temperature, or geochemical changes. Paleoecology and functional morphology of marine assemblages may provide critical data in order to identify increasing influence of predators in deep time and lead to robust, testable theories of ecosystem change.
Shallow marine invertebrate assemblages of the Late Triassic (235-199 Ma) may have experienced escalation due to increased pressure from shell-crushing predators. Common shelly invertebrates exhibit a variety of paleoecological shifts and developed new morphological features related to bioturbation, swimming, and cementation. The role of predators in driving these trends is tested with new quantitative data on specialized predator abundance during this period. In addition to fossil data, external driving factors are quantified and controlled using geochemical proxies, sedimentological field observations, and petrography. Early results suggest that (1) adaptations for resisting, avoiding, or escaping predation can be observed with synchronous increases in shell-crushing predators, and (2) a combination of paleoecological methods can be used to test theories of predator-prey relationships in the fossil record.