MK Hickox

Student Speaker | Étudiant.e
Traditional evolutionary theory has long asserted that adaptive divergence is unlikely to occur over fine spatial scales, as gene flow is expected to limit the effects of selection. However, with the advent of the concept of microgeographic divergence, the assumptions of classical evolutionary theory are being increasingly questioned. Little research has investigated the spatial scope of microgeographic divergence, particularly amongst highly dispersing terrestrial organisms. This scale is important to consider, as there must be a spatial scale at which microgeographic divergence is indeed not possible. In this study, I will investigate microgeographic divergence within the medium ground finch (Geospiza fortis) population of El Garrapatero (Isla Santa Cruz, Galapagos). Due to the dispersal abilities of the species, heterogeneity of the habitat, and the established literature on the study species, this population offers a unique opportunity to test the scope of microgeographic divergence. I will be leveraging a twenty-year dataset composed of G. fortis morphological measurements with the associated capture locations. I will analyze several phenotypic traits, including mass, beak measurements, wing chord, and tarsus, of the captured birds at each microsite to decipher phenotypic patterns of spatial sorting over time. By testing for morphological microspatial sorting, this study will provide insight into the ecological implications of microgeographic divergence and the spatial scale to which it applies, while reevaluating classical evolutionary theory. By assessing phenotypic spatial sorting of highly dispersing organisms over small spatial scales, this study will examine the scope of microspatial divergence, as well as the conditions in which it may occur.