1. When Genes Flow…
Gene flow= the movement of alleles between populations.
Occurs when individuals join new populations and reproduce.
Lots of gene flow = similar populations
Limited gene flow = different populations that could evolve into different species.
Genetic drift= a change in allele frequencies due to chance.
small populations are more likely to be affected by chance (alleles can have drastic changes)

2. Bottleneck Effect
Occurs when an event drastically reduces population size.

3. Founder Effect
Occurs when a few individuals start a new population.

4. Genetic drift has negative effects on a population.
less likely to have some individuals that can adapt
harmful alleles can become more common due to chance
Causes a loss of genetic diversity

5. Sexual selection- Process in which certain traits increase mating success (and therefore become more common in the population).
Females preferentially mate with males that display certain traits and pass these traits to their offspring.

6. intrasexual selection: competition among males
intersexual selection: males display certain traits to females