1. Evolution of Populations 16.1 pp. 299-302
Hardy-Weinberg Equilibrium describes populations that are NOT evolving, allele frequency is in equilibrium
5 conditions necessary:
No mutations
No migration
No natural selection
Large population size
Random mating
Random mating requires no sexual selection, a form of natural selection.

2. Evolution of Populations 16.2 pp. 304-308
Disruption of Genetic Equilibrium
Mutation = mistake in copying the genetic code
Can be single letters or entire genes
Can be good or bad
Natural selection can only act on those genes that are expressed so recessive genes can take a long time to be removed from a population
Common mutations: S

3. Evolution of Populations 16.2 pp. 304-308
Disruption of Genetic Equilibrium 2. Migration = individuals moving into or out of a population (adds or removes genes) Immigration = individuals move into the pop. Emigration = individuals move out of pop.

4. Evolution of Populations 16.2 pp. 304-308
Disruption of Genetic Equilibrium 3. Genetic Drift (small pop.)= loss of alleles in small populations (genes drift away) due to random events

5. Evolution of Populations 16.2 pp. 304-308
Disruption of Genetic Equilibrium 4. Non random mating = mating is rarely random, affected by: - location - timing - kinship - sexual selection

6. Evolution of Populations 16.2 pp. 304-308
Disruption of Genetic Equilibrium 5. Natural selection = environment favors certain traits over others - increased fitness for selected traits - individuals with those traits survive better, pass on those genes

7. Evolution of Populations 16.2 pp. 304-308
Disruption of Genetic Equilibrium
Types of Natural selection:
Directional selection = population shift in direction of selection
Examples:

8. Evolution of Populations 16.2 pp. 304-308
Disruption of Genetic Equilibrium
Types of Natural selection:
Disruptive Selection =
Selection toward the extremes (disruption of normal distribution)
-often new species
Examples:

9. Evolution of Populations 16.2 pp. 304-308
Disruption of Genetic Equilibrium
Types of Natural selection:
Stabilizing Selection =
Selection toward the average
- Focusing of traits

10. Evolution of Populations 16.2 pp. 304-308
Disruption of Genetic Equilibrium Western Grebes (mate for life): Sharptail Grouse:
Types of Natural selection:
Sexual Selection:
Again, choosing a mate directly affects fitness