1. Evolution of Populations
Genes and Variations

2. Genetic Variation and Gene Pools
Variation is studied in populations
Gene Pool: consists of ALL genes, including different alleles (ex: R and r)
Relative Frequency: number of times an allele occurs in a pool
Example - B (black fur)is at 40% frequency and b (brown fur) is at 60%.
Why is Black Fur (B)more common if it is only 40% of the alleles?

3. Evolution is the change of frequency of the alleles!
If the numbers change over time, then the population is evolving.
You try it: The gene for white moths is W, and for black moths is w.
What do you think the original percentages were before the industrial revolution?
What about after?
Are they evolving?

4. How do we get variation?
Mutation: change in DNA sequence, some are good and some can be “bad” for the species
Gene Shuffling: sexual reproduction and crossing over gives a new set of DNA each time we reproduce

5. Different Phenotypes
Some traits are simple and some are complex ex: widows peak is caused by a single gene
Single Gene Trait: has 2 alleles only
Polygenic Traits: 2 or more genes control the outcome
This leads to more phenotypes and variation. Ex: How many shades of eye color are their?