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Evolution: Evidence and Genetics Variation

Explore the gradual changes in species over time and discover evidence of evolution through fossils, comparative anatomy, and embryological development. Understand how natural selection and genetics contribute to variation within populations.

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Evolution: Evidence and Genetics Variation

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  1. Lab 8 Intro Genetics and Evolution

  2. Evolution • Gradual changes in a speciesover time • What’s the evidence?

  3. Fossils • Fossils show us gradual changes • Horse example looked at hoof development • p 203

  4. Comparative Anatomy • Homologous Structures- • Similar bone structure, different functions • pp 204-205

  5. Evidence: Embryological Development (p205-206) • Embryos look similar in closely related organisms • Demonstrate links between taxa • Echinoderm larvae are bilaterally symmetrical • Mollusca trochopore larvae are similar to Annelidia

  6. Evolution via Natural Selection • Overproduction • Variability • Differential Survivorship • Those with better adapt traits survive longer and reproduce more • Gradual Change • Selection pressures lead to change • Competition, predation, climate, amount of water

  7. Genetics & VariationGenes vs Alleles • Genes • are instructions on how to make proteins or traits • Alleles • Different version of the same gene

  8. Genetics VariationDominant vs Recessive • Dominant Alleles- • An allele that is always expressed when present • Recessive Allele- • Is not expressed when there is a dominant allele • Needs two copies of the recessive allele to be expressed R= Round r= Wrinkled

  9. Genetics & Variation • Each organism has 2 copies of every gene • Exceptions are found in plants and fungi • One copy comes from each parent

  10. Genetics & Variation Wife’s Mother Wife

  11. Genetics & Variation Bowman’s Brother

  12. Variation and Evolution • Multiple alleles = multiple phenotypes. • Creates variation within population or species

  13. Allele frequency graph • Change in the frequency alleles over time No Change Changing

  14. Hardy-Weinberg Principle Allele Frequencies remain stable over long-term unless: • Mutation • Gene Flow (Immigration or Emigration) • Genetic Drift • Nonrandom Mating (sexual selection, unequal sex ratio, etc…) • Natural Selection

  15. Genetic Drift • Random loss of alleles • Go To Simulation: http://darwin.eeb.uconn.edu/simulations/drift.html Run the simulation with different population sizes (10 times for each population size).

  16. Make sure you read • Read • p 199-200 (Intro and Darwin) • 203-213 (Evidence for Evolution to end) • Do Activities • p208 Genetic Drift (click here) • p209 Pepper Moth (click here) • p210 Florida Panther (click here) • p212 Fuchsia (click here) • Turn in Postlab 8 (given to you last week)

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