Allmon, Warren D.¹
(1) Paleontological Research Institution, Ithaca, NY

ABSTRACT: Sealevel, Climate, and the Causes of Marine Biological Diversity

Changes in sea level and climate (temperature) are two of the most frequent and, presumably, two of the most biologically significant long-term changes experienced by benthic marine faunas, and they have been pointed to frequently as important causes of evolutionary change. Yet we know very little about how evolution -- especially the origin of new species -- actually works during such environmental perturbations. This represents a major gap in our understanding of the long-term connection between environment and evolution. More explicit models of the relationship of species origin to environmental disturbance can contribute to addressing this problem.
The fossil record of Cenozoic mollusks on the Gulf and Atlantic coastal plains of the U.S. is among the most studied in the world, and includes frequent changes in sea level and temperature. Turritellid gastropods are one of the most diverse and abundant components of this record. Preliminary analysis of an emerging database of coastal plain Cenozoic turritellid species suggests that new generalizations about the connection between environmental and evolutionary change can be derived from examination of individual clade histories compared to fluctuations in temperature and sea level. (Changes in nutrients also likely played a role in this system, but paleoenvironmental data are currently inadequate to fully explore this.) This system may offer a model for analysis of other shallow marine benthic communities in the geological record.

AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004