Plasticity is how much a trait shifts between environments
- The idea
- Predict
- See it
- Why
- Check
The idea
“The genotype with the biggest values is the one that responds most to its environment.”
The biggest number in a table grabs your eye. It shows how large the trait gets, a separate question from how much it moves.
The short version
The mistake: The genotype with the biggest values is the one that responds most to its environment.
What's actually true: A genotype's level is how large its trait is, and its plasticity is how much the trait changes between environments.
- A reaction norm plots one genotype's phenotype across environments. Its height shows how large the trait is. Its slope shows how much the environment changes it.
- Phenotypic plasticity is the slope. To compare it, find how much each genotype's value changes between environments.
- Parallel lines mean the same response. If one sits higher in the same conditions, the genotypes still differ genetically.
On the exam: Plasticity is a difference. Subtract across environments for each genotype before you compare.