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Punctuated Equilibrium

Punctuated Equilibrium. Verses Gradualism. What Drives Evolution. 1-Isolation. Temporal Geographic Behavioral. 2-Artificial Selection. Did not drive evolution!!!. 2-Natural Selection. 2-Natural Selection. 3-Variation & Heritability. Sources of Genetic Variation.

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Punctuated Equilibrium

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  1. Punctuated Equilibrium Verses Gradualism

  2. What Drives Evolution

  3. 1-Isolation Temporal Geographic Behavioral

  4. 2-Artificial Selection Did not drive evolution!!!

  5. 2-Natural Selection

  6. 2-Natural Selection

  7. 3-Variation & Heritability

  8. Sources of Genetic Variation • Mutations – 300 mutations in our DNA that are different from our parents mutations • Only matter if they can be passed to next generation – skin cancer • Sexual Reproduction – remixes the genes your parents provide into new combinations of paired alleles • Lateral Gene Transfer – only in single celled creatures but significant to all evolution and current resistance to drugs. • Single Gene (allele selection) Vs Polygenic Traits (phenotype selection) & how natural selection works on them. • Type of Selection for Polygenic Traits: Directional / Stabilizing / Disruptive

  9. Founder Population

  10. Bottleneck

  11. Genetic Drift

  12. Evolution Vs Genetic Equilibrium Genetic Equilibrium = allele frequency in a gene pool does not change – sexual reproduction does not change change frequency. Hardy Weinberg principle = predicts allele frequency for a population and if it is wrong than it is likely that evolution is taking place. Disturbances to Equilibrium: Nonrandom mating – mate selection Small Population Size Immigration & Emigration Mutations Natural Selection Look at Darwin’s Finches pages 496-497

  13. Molecular Evolution • Molecular Clocks • Uses rates of neutral mutations in stretches of DNA to estimate the time that two species have evolved independently of each other – page 499 • Gene Duplication • Gene Families such as Hox genes • New copy genes evolve without changing the original • Hox Genes: Mutations to this gene is significant to the body plan • Dark Matter: Switches

  14. Microevolution & Macroevolution

  15. Mass Extinctions 5 recorded mass extinctions Ordovician (440mya) - 50% of animal families Devonian (360mya) - 30% of animal families Permian (250mya) - 50% of animal families, including 95% of marine species Triassic (210mya) - 35% of animal families Cretaceous (65mya) - 60% of animal species Recovery Time Ordovician - 25 million years Devonian - 30 million years Permian/Triassic - 100 million years Cretaceous - 20 million years Many other minor extinctions Background Extinction

  16. Mass Extinctions Current - Holocene Extinction

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