SICB Division of Phylogenetics and Comparative Biology (DPCB)

DPCB Researchers Database Entry

Rachel Collin

Evolution of reproduction and mode of development in marine invertebrates
Mode of development in benthic marine invertebrates (e.g., planktonic vs. benthic, feeding vs. non-feeding) has numerous evolutionary implications. Species with feeding larvae often spend weeks, months, or sometimes even years in the water-column. During this time they are subject to dispersal by oceanic currents and may travel vast distances. Species with encapsulated benthic development or short-lived, non-feeding larvae generally do not have much chance for dispersal in the water column before metamorphosis into a benthic juvenile. As a result of these differences in dispersal, species with planktotrophic development are believed to have higher levels of gene flow, less population structure, and larger geographic ranges than similar species with direct or lecithotrophic development. These emergent species-level characters have also been shown to result in lower rates of speciation and extinction in planktotrophic species than in direct developing species during the Mesozoic and Cenozoic.

I have used a comparative phylogenetic approach to understand the evolution of mode of development in marine invertebrates. My comparative data for calyptraeid gastropods show that evolutionary changes in mode of development may be large and rapid. I am currently interested in developing similar comparative datasets for other groups of marine gastropods. I am also beginning a project to understand population genetics of variation in development. By examining the heritability of and intraspecific variation in developmental features I hope to gain insight into the development of interspecific variation in life history characters.