What's the difference between reaction norms and phenotypic plasticity? I'm trying to understand better these two concepts, but I cannot see a clear difference yet. Reaction norm: "set of phenotypes that can be produced by an individual genotype when exposed to different environmental conditions" Phenotypic plasticity: "ability of individual genotypes to produce different phenotypes when exposed to different environmental conditions" Are phenotypic plasticity changes temporary changes in genes; are they an extension of the reaction norm?

I think it's a little simpler than what you describe- phenotypic plasticity is the abstract property of phenotypes differing with respect to environment, whereas a reaction norm is a particular environmental response.

So you might make an argument like this:

"Daphnia show extensive phenotypic plasticity in their morphology. For example, see the attached figure showing head morphology norms of reaction (y axis) of two Daphnia strains with respect to food richness (x axis)."

![enter image description here](

This is figure 9 from Woltereck's original publication on reaction norms. It shows that as you grow Daphnia with denser cultures of algae (their food), more individuals in the population show a distinctive head morphology. It shows further that the shape of the curve is similar between two Daphnia strains (solid and dotted lines). Each curve is what Woltereck called a norm of reaction.

Hope that helps.