1. Natural Selection on Single Gene Traits

2. Learning Objectives
Explain how natural selection affects single-gene traits
Describe what a polygenic trait is

3. Phenotype is Determined by Genotype
The number of phenotypes produced for a given trait depends on how many genes control the trait

4. Single-Gene Trait
A single-gene trait is controlled by a single gene that has two alleles. Only two phenotypes.

5. Natural selection on single-gene traits can lead to changes in allele frequency and evolution
The allele for dark colored moths became more common in the gene pool

6. Evolution of the Peppered Moth
YouTube Video
Evolution of the Peppered Moth

7. Stop Here

8. Turn to your neighbor and talk about what you think polygenic traits are. What is it? Which traits are polygenic?

9. Polygenic Trait
A polygenic trait is controlled by more than one gene. More than two phenotypes.

10. Let’s Explore Natural Selection on the Peppered Moth!

11. Polygenic Trait
Height is an example of a polygenic trait.

12. Class Height Measurement
Each student will have their height measured.
Record the height of each student in data table.
Graph frequency (y-axis) vs. height (x-axis)