Artificial selection 8 mutations in wild type genes

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Artificial Selection 8 Mutations in wild-type genes lead to desirable changes in the values of some of the traits Continuous use of “mutants” as breeders reinforces the trait value as additional mutations are acquired These are all GMO relative to the wild type, would likely not have survived natural selection
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Natural Selection Individuals within a population are different At least some of the differences are heritable Some individuals are better at surviving and producing offspring than others Success at survival and reproduction is not always just a matter of luck (but sometimes it is) often it is due to the variable traits they inherited traits they will also pass on to their offspring Success in survival and reproduction— fitness fitness does not mean more physically fit although that may be part of it 9
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Natural Selection 10
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Fitness “Fitness” in evolution = Darwinian fitness the capacity to survive and produce offspring that are themselves able to survive and reproduce Darwinian fitness is not necessarily correlated with physical fitness e.g. yellow legged gulls 11
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Yellow-Legged Gulls Muscle condition 5% low, 90% normal, 5% high Predation per group 50% low, 38% medium, 12% high 12
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Fitness is Relative An individual is not either fit or not fit an individual is simply more fit or less fit than other individuals A trait that increases an organism’s fitness relative to the fitness of other members of the species is an adaptation Such a trait value is said to be adaptive 13
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Testing Evolution Darwin’s four main postulates regarding descent with modification are testable the fifth, the age of the earth, we leave to geologists and astronomers Two examples flower color in snapdragons (partial controlled) size of beaks in finches (completely natural) 14
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Evolution of Flower Color Jones and Reithel 2001 experimental population, 48 flowers 1) Is there variability in flower color 75% white, 25% yellow 2) Is flower color heritable flower color controlled by one gene, two alleles S and s, S is dominant SS and Ss are white, ss is yellow 12 SS (white, 25%), 24Ss (white, 50%), 12 ss (yellow, 25%) 15
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