1. Mapping Human History

2. Microevolution: Four Primary Causes of Microevolution:
generation-to-generation change in a population’s frequencies of alleles
Below the species level!
Four Primary Causes of Microevolution:
1. Genetic Drift
2. Natural Selection
3. Gene Flow
4. Mutation

3. Genetic Drift is most effective in small populations!
1. Genetic Drift: a change in a population’s allele frequencies due to CHANCE.
Genetic Drift is most effective in small populations!

4. Small Populations May Experience…
The Bottleneck Effect-
Disasters randomly reduce the population size. The surviving population may not be representative of the original population’s gene pool (a version of genetic drift)

5. Gene Flow acts in opposition to Genetic Drift!
Populations may gain or lose alleles due to the migration of fertile individuals or gametes between populations.
Gene Flow acts in opposition to Genetic Drift!

6. Microevolution can lead to “Races” or even new species

7. Defining a Species: the Biological Species Concept
Defines a species as…
a population (s) whose members can potentially interbreed in nature to produce viable, fertile offspring, but who can’t produce viable, fertile offspring with members of other species

9. Reminders about Mitochondria

10. Weird Things About Mitochondria