Erick Peirson: The Conceptual Foundations of Adaptive Phenotypic Plasticity in Evolutionary Ecology

During the early 1980s, a rapid expansion of research literature concerning what its authors called phenotypic plasticity began to take shape. The scientists that contributed to this literature -- largely within the broad field of evolutionary ecology -- asked questions like, “How is phenotypic plasticity adaptive?”, “What is its genetic basis?”, “How might it evolve?”, and “How might it impact the direction and dynamics of evolutionary change?” They investigated adaptations in a great diversity of organisms, drawing on and reinterpreting concepts that geneticists had long used to describe the effect of environments on organismal development, such as the norm of reaction and genotype-environment interaction (GxE). What biologists often considered to be merely a source of noise or uncertainty in genetical and evolutionary investigations became an important object of investigation as an evolutionary phenomenon.

How did adaptive phenotypic plasticity become such an important object of investigation for evolutionary ecologists during this period?

The dominant mythology surrounding contemporary phenotypic plasticity research holds that empirical and theoretical investigations of plasticity in an evolutionary context were stifled by rampant "gene centrism" throughout the 20th century: researchers were too concerned (it is said) with demonstrating hereditary differences in organisms, and wrote off plasticity as simply an annoying source of experimental error. My dissertation offers a different perspective, by showing how the articulation of an evolutionary-ecological science of adaptive phenotypic plasticity in the 1960s through 1980s was contingent upon -- and intertwined with -- the emergence and conceptual evolution of what we now call evolutionary population ecology. Specifically, my dissertation focuses on the two-pronged hypothesis that the emergence of the contemporary science of adaptive phenotypic plasticity depended on two factors: (1) a dramatic change during the 1950s and '60s in how ecologists thought about the temporal and spatial scales of evolutionary change, and (2) the increasing use of phenotypically-oriented mathematical techniques (such as game theory and optimality modeling) that provided new languages for talking and reasoning about phenotypic evolution.

I use a combination of archival research, oral history interviews, and analysis of the published scientific literature to reconstruct key investigative pathways that produced unique and highly influential conceptual and theoretical approaches to investigating adaptive phenotypic plasticity. These reconstructions show not merely that decisions about the units of environmental change, organismal characteristics, and hereditary mechanisms are tightly linked in evolutionary-ecological models, but how scientists have navigated these issues in specific social, intellectual, and material contexts. I analyze how the specific contexts in which adaptive phenotypic plasticity was investigated during the 1960s through 1980s shaped assumptions and commitments hidden in the unique concepts and models that emerged from those investigations. This project informs ecological research and scientific policy-making by illustrating some consequences of those contingent assumptions and commitments for efforts to integrate evolutionary and ecological theory, using concrete cases from the history of science.

Material by EP is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. 2011131209, and NSF SBE Doctoral Dissertation Research Improvement Grant No. 1256752.