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Slide 2 Slide 3 Slide 4 Slide 5 Slide 6 Within a species, there is usually a great deal of variation among individuals. Slide 7 There are variations in skin color, hair color, hair curliness, eye color, blood type, height, etc. Human Variation Slide 8 Genetic Variations cannot be changed* *mutations ex: hair color, eye color, blood type, hair on mid- digits Results from differences in DNA, genes Inherited Variation Slide 9 Passed on to offspring Sources of Genetic Variation Gene Shuffling Sexual reproduction; different combinations/ expressions of genes Mutations Errors in DNA copying, environmental damage Slide 10 Is not passed on to offspring ex. body figure, certain skills, tattoos, piercings Results from individual activities, environ- ments Acquired Variation Slide 11 North side, upper branches South side, upper branches North side, lower branches South side, lower branches Apples The differences between apples are acquired during the growing season. Difference will not be inherited. Apples collected from different positions on the same tree. Slide 12 Most differences in a species are the result of inherited and acquired variations. Slide 13 low variancehigh variance Cheetahs Leopards Manatees Cuttlefish If a major disease swept through both populations, which species would have higher rates of survival? Slide 14 Clause Wedekind 1998 Bern University in Switzerland SWEATY SHIRT EXPERIMENT 49 men wore the same shirt for 2 days 44 women were asked to rank the shirts in order of smell preference the scientists measured the MHC genes (genes related to smell) of each male and each female the results found that women preferred shirt smells from males who had the most different MHC genes from their own Women preferred males whose paired offspring would have the greatest genetic variation