Evolving Plasticity in Natural and Artificial Systems
Date: 5 - 7 September 2016
Convenors: Tobias Uller (Lund, SWE), Thomas Flatt (Lausanne, SUI), Bernhard Voelkl (Bern, SUI)
In a three-day workshop 29 researchers from nine different countries working in biology, psychology, linguistics, computer science and robotics discussed the evolution of phenotypic plasticity of living organisms and artificial systems. Phenotypic plasticity is the ability of individual organisms to adjust to environmental change and as such it represents an important link between genes, the environment and the traits of an organism. The main questions addressed were: (1) How does plasticity evolve, and (2) How does it affect evolution? Keynote presentations on the evolution of reaction norms were given by Emilie Snell-Rood (University of Arizona) and Sue Foster (Clark University). This was followed by presentations by Guillermo Lorenzo (González Universidad de Oviedo), Sergi Balari Ravera (Universitat Autònoma de Barcelona) and Rainer Riemann (Universität Bielefeld) bringing in perspectives from linguistics and psychology. Keynote lectures on the second day were given by Sonia Sultan (Wesleyan University) and John Baker (Clark University) covering the origin and evolution of adaptations and by Stefano Nolfi (CNR) and Richard Watson (University of Southampton) outlining the evolution of plasticity in artificial systems. Finally, Olof Leimar (Stockholms Universitet) and Ton van Dooren (Université Pierre et Marie Curie) gave stimulating presentations on the evolutionary dynamics of phenotypic plasticity.
Among the participants there was general agreement that evolutionary dynamics – and with this the outcome of evolution – change if organisms have the ability to respond plastically to environmental change. Yet, the question whether this requires a substantially different way of how to conceptualize evolution, or whether plasticity can readily be integrated into contemporary evolutionary (population genetics) theory, led to heated debate. Central to this debate is the question which role plasticity plays in the evolution of traits, and whether that role is active and direct or not. Is plasticity just a property of a trait, or does plasticity precede evolutionary change and even influences the pathways of evolution through canalization and decanalization? If the latter scenario (referred to as "plasticity first") turns out being common, then this might require considerable revisions of what is considered as the standard evolutionary theory. Similarly, the – still somewhat controversial – role of epigenetic inheritance was extensively discussed in this context, since epigenetic mechanisms might underpin variation in and evolution of plasticity.
Overall, it was agreed that developmental processes so far have not received sufficient attention in the field and that their influence on evolution needs to be better integrated into evolutionary theory. Here, a round-table discussion was dedicated to the question which mathematical/statistical tools would constitute an appropriate tool-box for conceptualizing the influence of plasticity and development on evolution. Classical models incorporating plasticity as gene-by-environment interactions were discussed as well as approaches modelling plasticity in terms of a developmental program, stage-based models, niche construction models and transgenerational epigenetic models. These approaches have, so far, been applied in parallel and often in isolation; yet formalizing those models in a unifying framework will be a first step for incorporating all aspects of phenotypic plasticity into evolutionary theory.