• The topic of this special issue is “Evolutionary or plastic responses to climate change”. The underlying question – whether observed responses have a genetic basis or are expressions of phenotypic plasticity – is an empirical one, to which evolutionary theory can only contribute indirectly.
• In particular, current theory is unable to make quantitative predictions about the magnitude of plastic responses. Furthermore, the challenges discussed in the introductory paper by Merilä and Hendry do not apply to
• Much of the relevant theory has not been developed with climate change specifically in mind (a notable exception being models of “evolutionary rescue”).

In which ways can evolutionary theory contribute to the question at hand?

• Identify factors that influence the response to environmental change.
• Make qualitative predictions about the effect of different environmental and genetic variables.
• Provide rough rules of thumb for the magnitude of genetic (but not plastic, wee above) changes.
• Make suggestions about measurements and scaling (e.g. Herford et al. 2004, Hansen and Houle 2008, Gingerich 2009)

Our review will have the following structure

• Genetic responses (focus on expected rates and evolutionary rescue)
  • Univariate case
  • Multivariate case
• Plastic responses

Many quantitative traits have a polygenic basis and (initial) adaptation occurs mainly from standing genetic variation. In this case, evolutionary change can be predicted as <latex> \Delta \bar z = \sigma_g^2 \frac{d \ln \bar w}{d \bar z}</latex> (Lande 1976).

• The baseline: Stabilizing selection
• Sudden shift
• Moving optimum
• Incorporating stochasticity