BIOL 101 1nd Edition Lecture 21 Outline of Last Lecture I Observations II Conclusions III Natural Selection IV Viewpoints Outline of Current Lecture II Population Genetics III Hardy Weinberg Principle Current Lecture II 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 variation of 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 unsure that 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 seletion gene flow genetic drift mutation and the bottleneck effect B 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 time III Hardy Weinberg model of a non evolving population A Do non evolving populations exist No These 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 None Size Very large population Immigration Emmigration No gene flow Mating random Reproductive success 100 no natural selection B 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 each allele 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 HardyWeinberg equilibrium Population 490 A A dark blue 420 A a medium blue90 a a white What are the individual genotype frequencies in the population A A Dark Blue A a Medium Blue a a white What are the allele frequencies in the population Total alleles 2 000 A 2 490 420 1400 2 000 70 2000 a 2 90 420 2 000 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 1 2 genotype frequencies p2 AA 2pq Aa q2 aa 1 D Try an example problem Given 4 q webbed feet 6 p
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