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Assignment: General Biology & Ethics Worksheet Assignment: General Biology & Ethics Worksheet Assignment: General Biology & Ethics Worksheet A Case Study in the Methodology, Philosophy and Ethics in Science When asked what causes ulcers, some people will say stress, spicy food, or medication. Most will probably identify too much acid in the stomach. 1. If you wanted to test the excess acid hypothesis, which of the following experimental set ups would you use? Explain your answer. a. Examine ulcer patients of a range of ages and measure their stomach acid levels. b. Have volunteers drink alcohol and measure their stomach acid levels. c. Lower stomach acid levels of some volunteers (using drugs/antacids), and measure numbers of ulcers in all volunteers. d. Examine patients of a range of ages and measure the number of ulcers in each person. e. Put volunteers through a stress test and then measure their stomach acid levels. Consider the following experimental design to test the hypothesis: Doctors divide ulcer patients into two groups: • Group 1 received antacids and were instructed to take them 3x/day • Group 2 received sugar pills and were instructed to take them 3x/day After 3 months, the number of ulcers per patient was assessed. # of ulcers per patient 2. Predict what the results would look like if the excess acid theory was supported, and draw a bar graph below to reflect your prediction. Group 1 (antiacids) Group 2 (placebo) Treatment Group When studies like this are conducted, ulcer symptoms decrease with antacid use, but the ulcers return when patients stop taking the antacids. Therefore this is not a cure. So what’s the cause of ulcers, and can we find a cure? By 1886, a possible association between ulcers and spiral bacteria in the lining of the human stomach was noticed. It wasn’t until 1984 that this observation was explored. Dr. Robin Assignment General Biology & Ethics Worksheet Warren and Dr. Barry Marshall examined 100 ulcer patients through endoscopy. The vast majority were infected with the bacterium Helicobactor pylori. They concluded bacteria could cause ulcers and published their results in the premier medical journal, The Lancet. Their colleagues dismissed these findings. 3. Why might their findings have been criticized? One problem with Warren and Marshall’s study was they did not clearly establish “cause and effect.” To further support their hypothesis….. • Marshall swallowed a culture of H. pylori, which, after several days, caused nausea and vomiting and severe gastritis • In 1988 Marshall and Warren conducted a study where they randomly assigned 100 people with ulcers to receive one of two treatments: acid reducing drugs or antibiotics o In 90% of people treated with acid reducing drugs, ulcers eventually returned. o But ulcers returned in only 20% of those whose H. pylori infection was eliminated with an antibiotic. • Click here to ORDER an A++ paper from our Verified MASTERS and DOCTORATE WRITERS: Assignment: General Biology & Ethics Worksheet Other researchers also saw the same correlation of the bacterium and ulcers, and successful treatment with antibiotics. o In 80% to 90% of people with ulcers and H. pylori, antibiotics offer a permanent cure. 4. After these further studies, do you think cause and effect was well established? Explain your answer. And the outcome….. • Drs. Warren and Marshall had trouble getting their results published in scientific journals and presenting results at scientific meetings. • NIH guidelines recommending antibiotic treatment for ulcers were implemented in 1994. • Still, it took over 15 years and many more studies from researchers all over the world, before the “bacteria cause ulcers” hypothesis was accepted by the medical community. • Warren and Marshall received the Nobel Prize in Physiology or Medicine in 2005 for their discovery. 5. Identify an example from this case study of the following aspects of the scientific method: a. Hypothesis: b. Testing: c. Inductive reasoning: d. Communication: Order Now