Meeting Abstract

S3.1  Monday, Jan. 4  Does life evolve differently in the sea? GROSBERG, RK; VERMEIJ, G*; University of California, Davis; University of California, Davis rkgrosberg@ucdavis.edu

Between 85% and 95% of all living macroscopic species dwell on land; the rest are mainly marine. We argue that the extraordinary diversity on land is geologically recent, dating from the mid-Cretaceous period, about 110 million years ago. We suggest that the necessity and ability to be rare—that is, to maintain populations at low density—are critical to the attainment of high diversity. Fundamental differences in the physical properties of terrestrial and marine environments, notably the low cost of mobility to consumers on land, make it possible for terrestrial organisms to persist at far lower densities and achieve higher diversity than marine organisms. Increasing productivity beginning in the mid-Cretaceous led to an increase in the survival of populations at low density and to an increase in the intensity of selection for that ability, as well as for high mobility and habitat specialization. The preeminence of terrestrial as compared to marine diversity is therefore an historical phenomenon that is best explained by selection-related changes in mobility, dispersibility, and the evolution of partnerships.