Collaborative Research: Effects of a Regional Plio-Pleistocene Extinction Event on the Escalation of Predator-Prey Interactions

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As humans continue to transform the world's ecosystems through the loss of species, fragmentation of habitats and global redistribution of species, we are increasingly re-creating conditions not unlike those of past extinctions. How will species respond to such changes in their environment? Lineage-specific, habitat-specific, and regionally constrained information on what adaptive solutions work best in particular kinds of environments and selective regimes in the aftermath of crises is critical if we are to manage and anticipate the long-term consequences of human-induced environmental changes. Towards this goal of better understanding the effects of ecological losses on species interactions, PIs plan to test the hypothesis of escalation, which claims that as biological hazards become more severe adaptations to those hazards increase in expression. The study will focus on fighting conchs (snails of the Strombus alatus complex) and their crab predators in the abundant fossil record of the Plio-Pleistocene of Florida before and after a regional mass extinction event at the end of the Pliocene. Given a basic theoretical understanding of how changes in predation pressure should affect adaptation to enemies, and the previous inference that levels of predation peaked in the Pliocene and declined in the Pleistocene following the extinction event, escalation between fighting conchs and crabs is predicted to have slowed or halted after the Pliocene. The material that will be collected and studied for this proposal will also be used to develop hands-on, inquiry-based activities for teaching about evolution. In particular, secondary school students will be introduced to the concepts of fossils as records of biological evolution and environmental change, and shells as records of predator-prey relationships and adaptation, connecting to a number of National Science Education Standards.