Evolution of phenotypic plasticity in increasingly variable environments
Human-induced environmental change manifests not only in shifting average environment conditions, but also changes to the variability of these conditions. Adaptive phenotypic plasticity - or the ability for genotypes to adaptively express a range of phenotypes depending on the environment - is a way in which animals can cope with increasing variability.
As an NSF Postdoctoral Research Fellow in Biology at the University of Minnesota, I am utilizing the freshwater crustacean group, Daphnia spp., to reconstruct the evolution of adaptive phenotypic plasticity in nutrient metabolism and anti-predator traits through time. Daphnia leave hardy egg sacs - ephippia - in sediment layers at the bottom of lakes that can then be harvested and, using radioactive dating techniques, dated.
Through the LacCore sediment core collections at the University of Minnesota, we are able to conduct further analyses of sediment cores that can then been used to document nutritional changes in lakes through time, often as a result of human land use changes. Daphnia eggs are viable in sediment layers up to 700 years(!), and we use this unique fact of their biology to design developmental experiments that investigate the degree to which Daphnia have evolved plasticity in response to increasingly variable environments.