1. Alternative hypotheses (i. e
Alternative hypotheses (i.e., other than evolution by natural selection) to explain phenotypic change
Well-designed and well-executed experiments ALWAYS distinguish between competing hypotheses
Phenotypic plasticity
Random genetic drift
Sexual selection
Kin selection

2. Phenotypic plasticity
Expression of different phenotypes by the same genotype, often in response to environment
May be adaptive, non-adaptive, or maladaptive

3. Heritability VP = phenotypic variance VG = total genetic variance
VA = additive genetic variance
VD = dominance genetic variance
VE = environmental variance
VGxE = genotype x environment variance
VP = VA + VD + VE + VGxE
VG = VA + VD
H2 = VG / VP
h2 = VA / VP
When clones are planted in common gardens, are we estimating H2 or h2?
With parent-offspring regression, are we estimating H2 or h2?

4. Daphnia Is this phenotypic plasticity adaptive?
Is there genetic variation in phenotypic plasticity itself?

5. Is there genetic variation for plasticity?
Multiple isogenic lines (e.g., clones), grown in two or more common gardens having different environments
Compare “norms of reaction”
clone 1
trait value
clone 2
clone 1
clone 2
clone 3
clone 3
clone 4 1 2 1 2
Environment
In which of these populations can phenotypic plasticity evolve?