Transcript Gene Flow and Genetic Drift

WARM UP
1. Describe how evolution can be
thought of as both a fact and a
theory.
Gene Flow and Genetic Drift
Population Microevolution
• Individuals don’t evolve, populations do
– Small changes in gene frequency
– Can occur through gene flow or genetic drift
Gene Flow
• Migration can quickly change gene/trait frequency
– Especially in smaller populations
Genetic Drift
• Random chance can cause some
genes/traits to disappear
– Especially in small populations
Genetic Drift
• Bottleneck
– Severe drop in population
– Leaves a small sample of
traits (good or bad)
• Inbreeding
Genetic Drift
• Bottleneck
Genetic Drift
• Founder effect
– A migratory bottleneck
– A few organisms start a new population
• Inbreeding
WRAP UP
• Compare and contrast
bottlenecks and the founder
effect.
WARM UP
1. Explain how the terms
microevolution and population
evolution are related.
WRAP UP
1. Compare and contrast gene flow and
genetic drift.