Driving Forces of Evolution

Driving Forces of Evolution1. Genetic Change2. Natural Selection3. Reproductive Isolation4. Variable Fluctuation – “life is not static”

1-Variation & Heritability

1- Sources of Genetic Variation

2-Artificial Selection

Did not drive evolution!!!

2-Natural Selection

2-Natural Selection

3-Reproductive Isolation

3 - Founder Population & Genetic Drift

4 - Genetic Drift

4 - Bottleneck

4 – Speed:

4 - Mass Extinctions5 recorded mass extinctions1. Ordovician (440mya) - 50% of animal families – land plants

absorbing CO2 – same dominant life after2. Devonian (360mya) - 30% of animal families –

meteor/volcanoes3. Permian (250mya) - 50% of animal families, including 95% of

marine species - volcanoes4. Triassic (210mya) - 35% of animal families –

meteor/volcanoes5. Cretaceous (65mya) - 60% of animal families = meteor

Recovery Time6. Ordovician - 25 million years7. Devonian - 30 million years8. Permian - 100 million years9. Triassic - 100 million years10. Cretaceous - 20 million years

Many other minor extinctionsBackground Extinction

Measurement - Hardy Weinberg Principle

Hardy Weinberg principle – if allele frequency changes than evolution is taking place.

right side = no evolution1. Non-random mating ------------random mating2. Small Population Size------------large3. Immigration & Emigration------none4. Mutations---------------------------none5. Natural Selection------------------none