BIOL 1361 1nd Edition Lecture 2 Outline of Last Lecture I. SyllabusII. Emergent PropertiesIII. Life Requires Energy Transfer & TransformationIV. Life Depends on Genetic InformationV. Organisms Interact with the Biotic & Abiotic EnvironmentVI. Evolution by Natural SelectionOutline of Current Lecture I. An end to Ulcers? – Case Study in the Scientific MethodII. Important Aspects of Experimental DesignCurrent LectureI. An end to Ulcers? – Case Study in the Scientific Methoda. Dr. J. Robin Warren: (Pathologist)i. 1979 examines stomach biopsies of patients with various stomach ailmentsb. Dr. Warren though he sawi. Heliocobacter pylori ( a new species of bacteria)ii. But no one believed him, they thought the stomach was too acidic for bacteria to survivec. So Dr. Warren..i. Used a special stain that highlights bacteria on his slides ii. This convinved his colleagues that the bacteria were thereThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.d. Alternative explanations (hypotheses)i. The biopsy specimens were contaminated after samples were taken from the patientsii. The bacteria live in the stomach, but to no damageiii. The bacteria are an opportunistic..e. Dr. Barry J Marshall joins Fr. Warren’s researchi. Hypothesis: Bacteria CAUSE stomach ulcersf. Their first survey studyi. 100 stomach ulcer patients surveyed (biopsy taken)ii. 100% had H. pylori presentiii. Btw, there is no control groupII. Important Aspects of Experimental Designa. Testable hypothesis – a way to measure a response and a way to divide groups upinto:i. Control and Treatment Groupsii. Experimental Design1. Independent Variable: factor thought to cause a change in the dependent variablea. Treatment groupsi. Control groupii. Experimental group(s)b. Number of individuals per treatmentc. Quantifying treatment variable2. Controlled variable(s): characteristic(s) held constant across treatment groupsa. Demographics: age, gender, BMI, ethnicity, etc.3. Dependent Variable: response being measureda. Amount of acidb. Number of ulcersc. Presence/abundance of bacteriab. Actual results of Warren and Marshall’s studyi. When treated with antibiotics, 80% of patients were permanently cured of their ulcersii. Dr. Marshall (who did not have ulcers) swallowed a flask of H. Pylori1. In a week he suffered symptoms of gastritis and had H. Pylori populations in his stomach2. He cured himself with an antibiotic
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