Evolution of Morphometric Variation in Side-blotched Lizards (Uta stansburiana)

By Khoa Nguyen
Whitman College, Walla Walla WA

The amazing diversity in animal body forms that exists today represents one outstanding example of evolution through the means of dynamic selective pressures. Such selective pressures can include limits on resources (e.g. habitat availability, suitable mates) and the existence of threats (e.g. predation pressure, disease). These factors ultimately vary across space and time. As a result, any or all of these possible selective pressures may have significant effects on the morphology (form and structure) of organisms. By utilizing an intraspecies approach, side-blotched lizards represent an ideal species with which to study the effects and consequences of co-dynamic selective pressures on body morphology. Correlations between two selective pressures: predation and habitat structure were made across six distinct populations of Uta. Insight into the potential variation in body morphology traits across these distinct populations allows us to better understand the extent of natural selection in shaping organisms in their unique ecological contexts.