Can Changes in the Larval Developmental Modes of Olivella in the Caribbean Neogene Be Used as a Reliable Productivity Proxy? (thesis)

Abstract

The Closure of the Isthmus of Panama functions as an excellent natural experiment because of our knowledge of the geologic record and the changing environment that influence the temperature, salinity, nutrients, and productivity of each area. The modern day Caribbean resembled the Pacific before the Closure of the Isthmus of Panama. The present day Pacific can serve as an analogue for the ancient Caribbean (Erwin et. al 2011). Extending this thought, life modes that are common within the modern Pacific should be present in the ancient Caribbean (Fortunato 2004). This provides an opportunity to examine how evolution was influenced by the changing productivity within each environment. The Closure of the Isthmus of Panama provides a clear study area in which to test whether environmental or ecological change drives evolution. The two environments generated by the closure provide an excellent opportunity to see how organisms evolve in response to their environments. In this paper, I will be focusing primarily on the physical changes in the environment, specifically planktonic productivity. The fossilized remains of gastropods, bivalves and bryozoans provide an opportunity to study and track these changes. [From Introduction]