DISSERTATION RESEARCH: Temperature-Dependent Phylogeography and Limits of Thermal Tolerance in Anolis carolinensis

Harvard University, Cambridge MA

Investigators

Abstract

This project aims to understand the physiological stresses that limit thermal tolerance in terrestrial ectothermic ("cold-blooded") animals (such as reptiles, amphibians and insects) and how those limitations affect a species' ability to survive changes climate. The hypothesis that extreme temperatures prevent all ectothermic species from effectively using oxygen has been widely applied to explain the limits of thermal tolerance. However, this hypothesis has been most heavily tested in aquatic species, raising the question: Does the same physiological stress effect air breathing species? Using the green anole lizard (Anolis carolinensis), the investigators seek to answer this question by combining physiological experimentation with genome sequencing to directly compare gene response under extreme temperatures to known genetic responses to hypoxia. Through this approach, the investigators seek to shed valuable light on the physiological mechanisms and evolutionary processes that allow terrestrial ectotherms to survive, function, and adapt to novel thermal niches. In order to fully understand how climate change will affect biodiversity it is essential to integrate information about environmental change with data about species' ability to buffer, acclimate, and adapt to that change via physiological and genetic mechanisms. This project serves to accomplish this by combining information about thermal differences within the range of a species with the wealth of knowledge on the thermal biology of lizards and genomic resources only made available within the last few years. Combining these tools will allow for better predictions of how changes in climate will affect species' ranges and abundances around the world. This research will also result in the training of a graduate student and will provide research experiences for several undergraduates.