1. Chapter 17: Evolution of Populations

2. Chapter 17.1 (Pgs 482-486): Genes and Variation

3. Phenotypic Variation Most organisms contain two sets of genes
One allele from each parent
Different combinations of alleles and environment produce variation in phenotypes
Natural selection acts directly on phenotypes, not the alleles

4. Populations and Gene Pools
A group of individuals of the same species that mate and produce offspring is called a population
These individuals share a gene pool, all the genes and alleles for each gene in a population

5. Allele Frequency
The # of times an allele occurs in a gene pool, compared to the total # of alleles for that gene
Evolution occurs when allele frequency in a population changes over time
Populations, not individuals, evolve

6. Single-Gene Traits Are controlled by only one gene
Only have two alleles
May only have two or three distinct phenotypes

7. Polygenic Traits Are controlled by two or more genes
Each gene has two or more alleles
Has many possible genotypes and even more different phenotypes