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Objectives

Objectives. Use data (evidence) to make claims about variation , fitness , selection and evolution in populations. Apply the general definition of Natural Selection and the concept of trade-offs to specific cases (e.g., guppies and antibiotic resistance in bacteria). Sex and Guppies.

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Objectives

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  1. Objectives • Use data (evidence) to make claims about variation, fitness, selection and evolution in populations. • Apply the general definition of Natural Selection and the concept of trade-offs to specific cases (e.g., guppies and antibiotic resistance in bacteria)

  2. Sex and Guppies http://www.pbs.org/wgbh/evolution/sex/guppy/gallery.html

  3. Trade-offs Initial population: Mostly drabLOW level of predation Time 1: Number of guppies: 227Number of generations: 5Number of weeks: 112 Time 2: Number of guppies: 232Number of generations: 12Number of weeks: 407

  4. Trade-offs Initial population: Even mixHIGH level of predation Time 1: Number of guppies: 171Number of generations: 4Number of weeks: 57 Time 2: Number of guppies: 100Number of generations: 7Number of weeks: 203

  5. Trade-offs • What would happen if... • Initial population: • EVEN mix of guppy coloration • MEDIUM level of predation? • What would the population look like after 7 generations? Make a prediction. You can test your prediction at: http://www.pbs.org/wgbh/evolution/sex/guppy/low_bandwidth.html

  6. Trade-offs: define Each trait may have both costs and benefits. It is impossible for any population of organisms to evolve optimal solutions to all agents of selection at once.

  7. Antibiotic resistance • Do you use antibacterial soap? Why or why not? Discuss in your groups. Reading in Angel: Microbes: What They Do & How Antibiotics Change Them Maura Meade-Callahan Antibacterial?

  8. CQ Mutation acts directly on …. • DNA • RNA • Amino acids • Protein • Phenotype

  9. CQ Fitness is …. • Absolute • Relative

  10. Antibiotic Resistance in Bacteria: an experimental approach

  11. Antibiotic Resistance in Bacteria: an experimental approach • Redraw this model and label: • Bacterial lawn • Inhibition zone • Discs of antibiotics • Label a point on the model where bacterial are likely most resistant to the antibiotic.

  12. Variation and Antibiotic Resistance • Do you think there is variation among these bacteria? Explain.

  13. Variation and Antibiotic Resistance • Do you think there is variation among these bacteria? Explain. • What is the origin of this variation? • Is the variation heritable?

  14. Fitness and Antibiotic Resistance • Does the environment vary across the Petri plate?

  15. Fitness and Antibiotic Resistance • Does the environment vary across the Petri plate? • Are these bacteria equally fit in all environments?

  16. Antibiotic resistance: Selection Describe this graph. What can you say about: • Variation? • Fitness? • Selection?

  17. Antibiotic Resistance: putting it all together Create a model that demonstrates the evolution of an antibiotic-resistant bacteria population. Label your arrows with processes! Start • Key to figure: • Blue = antibiotic-sensitive bacteria • Orange = antibiotic-resistant bacteria • x = antibiotic End

  18. Antibiotic resistance • Has your opinion about antibacterial soap changed? Reading in Angel: Microbes: What They Do & How Antibiotics Change Them Maura Meade-Callahan Antibacterial?

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