BIOL 101 1nd Edition Lecture 21 Outline of Last Lecture I. ObservationsII. ConclusionsIII. Natural SelectionIV. ViewpointsOutline of Current Lecture II. Population GeneticsIII. Hardy Weinberg PrincipleCurrent LectureII. Population Genetics Charles Darwin – In 1859, published theory of NS, without knowing about inherited traits/genes (Gregor Mendel – 1860’s his work was not recognized until 40 years after the Origin of Species was published). Darwin, therefore, did not understand WHERE the variationof individuals came from. Interestingly, Darwin’s theory was attacked because of the lack of understanding of genes—it was argued that if two animals were blended (like horse and zebra) traits would be diluted and offspring would never have clear advantages.) Darwin was so unsurethat he even stopped arguing his theory!A. = Modern synthesis (1940’s)- The ideas of Darwin and Mendel I together. How is it different from Darwin’s theory of NS?1. It recognizes 4 processes of evolution, not just natural seletiongene flow, genetic drift, mutation, and the bottleneck effectB. NS acts on individuals but the effect is a change in the population C. Population group of organisms of the same species living at the same time/place D. Microevolution – Changes in allele frequencies over timeIII. Hardy-Weinberg model of a non-evolving population A. Do non-evolving populations exist? NoThese 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.What 5 conditions would have to be met?Mutations? NoneSize? Very large populationImmigration/Emmigration? No gene flowMating? randomReproductive success? 100% no natural selectionB. Hardy-Weinberg Principle (1908): No matter how many times alleles are segregated into different gametes and united in different combinations by fertilization, the frequency of eachallele in the gene pool will remain constant unless other factors are operating.Butterfly example: an imaginary butterfly population is in genetic equilibrium (a.k.a. “Hardy-Weinberg equilibrium”). Population: 490 A/A –dark blue 420 A/a- medium blue90 a/a- whiteWhat are the individual genotype frequencies in the population?A/A- Dark BlueA/a- Medium Bluea/a- whiteWhat are the allele frequencies in the population? Total alleles =2,000A = 2 (490)+420 = 1400 =70%2,000 2000a = 2(90)+4202,000 = 30%What will the individual genotype frequencies be in this population in the next generation if nothing other than sexual reproduction is occurring?A(.7) a (.3) A (.7) .49 A (.3)C. HW equations to know: p = dominant trait; q = recessive trait 1. allele frequencies = p+ q =12. genotype frequencies = p2(AA) + 2pq (Aa)=q2(aa) =1D. Try an example problem:Given: .4=q webbed
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