Lecture_5_Macroevolution - 6/15/2011 Micro- vs....

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6/15/2011 1 Macroevolution LS1: Summer Session A June 29, 2010 Micro- vs. Macroevolution Microevolution: An example Antibiotics An antibiotic is a drug that kills bacteria Prior to the development of penicillin, bacterial infections were the leading cause of death worldwide Antibiotics Antibiotics target bacterial cellular structures and processes that are different than eukaryotic cells How do antibiotics work? There are 7 main types of antibiotics, but each affects bacterial cells, which are different from human cells Penicillin, for example, breaks down bacterial cell walls
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6/15/2011 2 Resistance to antibiotics Pathogenic bacteria may develop resistance to antibiotics Mutation of their own genes Acquiring resistance genes from other bacteria Resistant strains difficult to treat with conventional antibiotics Resistance is a form of evolutionary adaptation Natural selection acts quickly on some populations Variation Heritability Differential reproductive success Bacteria are an example of rapid response to natural selection. Resistant bacteria are found within years of an antibiotic’s introduction. Macroevolution Macroevolution refers to large-scale changes (often) over long periods of time Can result in dramatic changes in organisms and lineages Two important concepts that underlie macroevolution 1. Geologic time The earth is very old, and life on earth is also very old This provides ample time for dramatic evolutionary change 2. Genetic control of embryological development can lead to extreme changes in organisms even without vast quantities of time Geologic time
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This note was uploaded on 09/08/2011 for the course LS 1 taught by Professor Thomas during the Summer '05 term at UCLA.

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Lecture_5_Macroevolution - 6/15/2011 Micro- vs....

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