Evolution in Action - PowerPoint PPT Presentation

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Evolution in Action

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  1. Evolution in Action

  2. “A turn for the Worse” pg. 59 • Scenario

  3. A Turn for the Worse (pp 58-60) Attendants wheel the teenage girl into the operating room as her mother waits anxiously in the sitting room. The girl’s appendix is so severely inflamed that the doctor worries that it might rupture before she can operate. In spite of the danger, the operation goes smoothly. The patient is then taken to the recovery room. 30 minutes later, she regains consciousness and speaks to her mother.

  4. A Turn for the Worse (cont’d) • All seems to be going well in the first 24 hours after surgery. However, on the following day, the girl begins to run a fever, which rises quickly. Her doctor realizes that she has contracted an internal infection during surgery. • The girl has a bacterial infection. A strain of Staphylococcus bacteria contaminated the open wound during surgery. Will she survive the infection??

  5. Scenario1: • The year is 1925… The girl becomes delirious from fever; in a few days, she dies.

  6. Scenario 2 • The year is 1945 The girl receives an injection of the antibiotic penicillin, followed by repeated doses. Within 24 hours, her fever is reduced. In a week, she is released from the hospital, well on her way to recovery.

  7. Scenario 3 • The year is 1965 The girl receives an injection of the antibiotic penicillin, followed by repeated doses. Despite the treatment, her fever continues, and she becomes delirious. In a few days, she dies.

  8. Year1919 World War I: Soldiers would die, not because of wounds, but because of infections.

  9. Bacteria growing on a petri dish Baby infected with a Staphylococcus bacteria

  10. Year 1928 Alexander Fleming observed that bread mold killed the bacteria growing on his experimental petri dishes. This was discovered out of pure luck.

  11. Year1939 Oxford University isolated the antibiotic penicillin from the mold Penicillium which grows on bread!

  12. Year 1941 Large-scale production of penicillin begins.

  13. How does bacterial resistance happen?

  14. Why was there an increase in resistant bacteria after 1945? See pg. 60

  15. Go to pg. 59 Assignment: Do #2 • Write 1 paragraph for each scenario, explaining why this would have happened during this time period. • 3 paragraphs total !!!! • NOTE: • Use graph and need to know to provide evidence for your paragraphs. Pg 60-61

  16. “Need to know” • Antibiotics: Medicine toxic to certain bacteria. These are used to fight bacterial infections. Ex. Penicillin • An antibiotic can kill only a limited number of bacteria. Those that survive are said to be resistant or tolerant to the antibiotic, thus will survive.

  17. “Need to know” • Bacterial variations that help them survive, allow them to reproduce, and pass on their “successful” genetic material to future generations. RESULT: a “resistant” population (The antibiotic becomes ineffective)

  18. Use the graph to answer the following on a sheet of paper: Decide why the outcomes for the 3 scenarios are different. Write an explanation as to why EACH outcome is possible at that time in history. Graph: Analysis