Thursday/Jeudi, May/Mai 9
8:30-10:30
IEE symposium
The Evolution of Adaptive Plasticity
Location/Lieu: Shediac A
Chair/Animé par: Alexander Little (McMaster University)
8:30-9:10
Draghi, J.A., Miller, C.M.
Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
Ecological constraints and promoters shaping the evolution of plasticity
Adaptive plasticity is a potent but relatively rare strategy by which organisms can deal with heterogeneous environments. While theory can predict when plasticity is favorable, to understand its distribution in nature we must also understand the selection pressures acting on the initial mutational steps toward plasticity. In this talk I discuss a series of models designed to reveal how the evolution of plasticity may be constrained by pleiotropy or incomplete information, and how dispersal can sometimes alleviate these constraints. These models emphasize the multiple roles of spatial heterogeneity across scales. Spatial heterogeneity not only shapes selection on plasticity but also can impede and guide dispersal, creating ecological opportunities that may catalyze the evolution of innovative changes like plasticity. Together, these models point to underappreciated ways in which complex environments can help elicit complex adaptations.
9:10-9:50
Dworkin, I.
Department of Biology, McMaster University
A significant Genotype-by-interaction term in an ANOVA tells you nothing about the evolution of phenotypic plasticity: Towards a measurement-informed approach to the study of the evolution of phenotypic plasticity
Evolutionary causes and consequences of phenotypic plasticity have long been, and continue to remain, an area of active research. In part, this is due to the observation that trait expression - from gene expression, through cellular architecture, physiology, morphology, behaviour and ultimately organismal performance - depend to varying degrees, on environmental factors. This is generally coupled with the observation that the degree of environmental sensitivity of trait expression, depends not only on the agent of plasticity (the environmental variables), or the target phenotype, but on genetic variation in the degree of plasticity. Evaluating Genotype-by-Environment (GxE) interactions has played a prominent role in the phenotypic plasticity literature for decades. Despite this, and the evidence that GxE is almost as common as plasticity itself, our understanding of the relative contributions of GxE (along with genetic and environmental effects per se) to phenotypic variation is inadequate to answering broader questions regarding plasticity. In this talk I argue that this is in large part due to how biologists frame results of statistical modeling of experimental work including GxE, and in particular how focusing on ANOVA tables (and p-value centric approaches) is limited in value. I will describe how developing biologically meaningful measures and directly assessing magnitudes of effects enhances interpretation, and utility to all researchers. I will discuss these issues through examples from our own work on the evolution of sexual size and shape dimorphism within and among species of Drosophila.
Chair/Animé par: Alexander Little (McMaster University)
8:30-9:10
Draghi, J.A., Miller, C.M.
Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
Ecological constraints and promoters shaping the evolution of plasticity
Adaptive plasticity is a potent but relatively rare strategy by which organisms can deal with heterogeneous environments. While theory can predict when plasticity is favorable, to understand its distribution in nature we must also understand the selection pressures acting on the initial mutational steps toward plasticity. In this talk I discuss a series of models designed to reveal how the evolution of plasticity may be constrained by pleiotropy or incomplete information, and how dispersal can sometimes alleviate these constraints. These models emphasize the multiple roles of spatial heterogeneity across scales. Spatial heterogeneity not only shapes selection on plasticity but also can impede and guide dispersal, creating ecological opportunities that may catalyze the evolution of innovative changes like plasticity. Together, these models point to underappreciated ways in which complex environments can help elicit complex adaptations.
9:10-9:50
Dworkin, I.
Department of Biology, McMaster University
A significant Genotype-by-interaction term in an ANOVA tells you nothing about the evolution of phenotypic plasticity: Towards a measurement-informed approach to the study of the evolution of phenotypic plasticity
Evolutionary causes and consequences of phenotypic plasticity have long been, and continue to remain, an area of active research. In part, this is due to the observation that trait expression - from gene expression, through cellular architecture, physiology, morphology, behaviour and ultimately organismal performance - depend to varying degrees, on environmental factors. This is generally coupled with the observation that the degree of environmental sensitivity of trait expression, depends not only on the agent of plasticity (the environmental variables), or the target phenotype, but on genetic variation in the degree of plasticity. Evaluating Genotype-by-Environment (GxE) interactions has played a prominent role in the phenotypic plasticity literature for decades. Despite this, and the evidence that GxE is almost as common as plasticity itself, our understanding of the relative contributions of GxE (along with genetic and environmental effects per se) to phenotypic variation is inadequate to answering broader questions regarding plasticity. In this talk I argue that this is in large part due to how biologists frame results of statistical modeling of experimental work including GxE, and in particular how focusing on ANOVA tables (and p-value centric approaches) is limited in value. I will describe how developing biologically meaningful measures and directly assessing magnitudes of effects enhances interpretation, and utility to all researchers. I will discuss these issues through examples from our own work on the evolution of sexual size and shape dimorphism within and among species of Drosophila.