Phenotypic resilience and evolutionary adaptation in changing environments

Cameron Ghalambor

Colorado State University, USA

Changing environmental conditions, such as those brought about by climate change, represent a form of directional selection. Organisms cope with changing environments and altered selection pressures on different timescales through a diversity of mechanisms. Phenotypic plasticity, or the capacity of a given genotype to produce different phenotypes, is the initial rapid response of an organism to altered environmental conditions. Such plasticity may be expressed in the short-term (acute changes that are often reversible) or in the longer term (developmental changes that may not be reversible). When plastic responses are beneficial in the face of environmental change, they can be considered adaptive because they result in phenotypic resilience. Yet, our understanding of the longer-term evolutionary consequences of plasticity remains largely unknown, despite its importance for predicting adaptive evolution. Here, we review theoretical and empirical work investigating the role of plasticity in evolutionary adaptation. We focus on different kinds of plasticity (adaptive and non-adaptive) in response to short- and long-term changes in temperature and the selective pressures that act on these responses. We then review how these selective pressures have resulted in geographic variation in plasticity between temperate and tropical regions and the implications of this variation for predicting the response to climate change. We conclude that, without a fundamental understanding of an organism’s physiological tolerance, predicted changes in temperature are a poor metric for understanding the consequences of climate change.