1. What other mechanisms for evolution exsist?

2. List 3 sources of genetic variation.
Mutation
Independent assortment
Crossing over/recombination
Random fertilization

3. Human Impact Selection
Artificial selection: When reproductive success is determined by humans. We are the selective agent not the environment.

4. Ex. Dog Breeds

5. Ex. Food Crops

6. Other Evolutionary Forces
Evolutionary change is also driven by random processes.
Other Evolutionary Forces

7. Genetic Drift
Random, non-selective, changes in allele frequency due to chance.
Ex: founder effect and bottleneck
Has a larger effect on smaller populations, since each individual is more of the total alleles.
Decreases genetic variation

8. Founder Effect
The descendants of a small, founding population have different allele percentages than the population the founders came from.

9. Ex. Amish Populations and polydactyly

10. Bottleneck Effect
The survivors of a catastrophic decrease in a population (ex. Natural disaster!)may have a different allele frequency than the pre-bottleneck population

11. Ex. Modern Cheetahs are all genetically similar due to 2 bottlenecks

12. Gene Flow
Movement of alleles due to immigration (in) and emigration (exit). Increases genetic variation

13. Example: Modern Human Migration

15. Sexual Selection
Persistence of traits that signify fitness and aid in reproduction

16. Ex. Peacocks are male.

18. Evolution Misconception Alert!
Misconception: Evolution is “random”. Evolution is a change in allele frequency in a population. That change involves random forces (ex. Genetic drift) and selective processes (ex. Natural selection).