BIOL 112 1st Edition Lecture 6 Outline of Last Lecture I. Voyage of the H.M.S. BeagleA. ObservationsII. Post VoyageIII. Alfred Russel Wallace (1823-1913)IV.Factors that Influenced DarwinV. Darwin’s Thinking ProcessA. Three ObservationsB. Two ConclusionsVI.What we Know NowVII. Darwinian EvolutionVIII. Tests of Darwin’s TheoryIX.Moth SelectionX. Selection in Action — PenicillinXI.Natural Selection in ActionXII. SphecomyrmaXIII. TiktaalikXIV. ArcheopteryxXV. Other PhenomenaA. Moth-Bee MimicryB. Müllerian MimicryXVI. Status of Darwin’s TheoryThese 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.Outline of Current LectureXVII. Darwinian TheoryXVIII. Darwin vs. MendelXIX. Important TermsXX. Hardy-Weinberg EquilibriumXXI. Mathematical ModelingXXII. Condition #1: Large PopulationCurrent LectureI. Darwinian TheoryToward the end of the 19th century, Darwin’s theory was in trouble:•Couldn’t explain inheritable•If favorable gene combinations are selected for, how can you keep them together through several generations?•Standard genetic model at the time was blending inheri-tanceNo one was familiar with Mendel’s work yet (and if they were, they didn’t understand it)By the turn of the 20th Century, Mendel’s work was “rediscovered” by Hugo de Vries•Dutch geneticist•discovered mutations (new alleles)•found and publicized Mendel’s papersII. Darwin vs. MendelEvolution scientists realized the need to revise Darwin’s Theory to in-clude major parts of Mendelian GeneticsDarwin-Mendel Genetics became synthesized together in the 1920s and 1930s by Fisher, Wright, and HaldaneProduct is called Neo-Darwinian Theory of Evolution. Two paradigms were combined into one:•Darwin Natural Selection acting on variations in pheno-types•Mendel Genetic Variability: mutations and recombinations; and Principles of HeredityEvolution became a change in the genetic content of a population overtimeIII.Important TermsGene Pool: Sum of allgenetic information in areproducing populationAllele (Gene) Frequen-cies: Relative proportionof alleles in a populationGenotype Frequencies:Relative proportion ofgenotypes in a popula-tionWhat happens if allelefrequencies change?Evolution has occurred,by definitionPopulation Genetics: Application of Mendelian principles to populations of organismsThe image to the right can help solve for allele frequencies based on phenotypes from a parent populationIV.Hardy-Weinberg EquilibriumDifferences from Classical Mendelian Genetics:We are considering all eggs and all sperm (pollen) in the reproductive population, not just those from two organisms in one breeding pairConditions to be met to work mathematics:•Breeding population is very large•No mutations in population•No immigration or emigration - no one comes in from the outside or leaves to change the population genotypes•Reproduction is random - the ability for all genotypes to contribute to the gene pool is equal; genotypes is not related to the success of the future populationIf all conditions are met, the population is in a stable state in which al-lele frequencies and genotype frequencies will not change from gener-ation to generationPopulation is in Hardy-Weinberg EquilibriumPopulation will not evolve unless outside forces intervene. Thus “out-side forces” will tend to cause evolution (allele frequency change)Mathematical formula derived from the Hardy-Weinberg ModelBinomial Equation:•Starting with allele frequencies: f(A) = p; f(a) = q;•(p+q)2 = 1•p2 + 2pq + q2 = 1Thus, you can identify genotype frequencies:•f(AA) = p2•f(Aa) = 2pq•f(aa) = q2How to solve for p and q:•p = ( 2(p2) + 2pq ) / 2(population) OR 2 times the frequency of homozygous dominant plus the heterozygous all divided by 2 times the total popula-tion —> p = 2f(AA) + f(Aa) / 2(AA+Aa+aa)•q = ( 2(q2) + 2pq ) / 2(population)OR 2 times the frequency of homozygous recessive plus the heterozygous all divided by 2 times the total popula-tion —> q = 2f(aa) + f(Aa) / 2(AA+Aa+aa)There are practice Hardy-Weinberg problems posted on Dr. Aufder-heide’s eCampus page. There will be a couple of these problems on theexam, so make sure you practice them! I will do one example on the study guide.V. Mathematical Modeling H-W allows mathematical modeling of gene frequencies and evolutionPermits quantitative predictions of evolutionary trends in populationPopulation is stable (no evolution) when in Hardy-Weinberg equilibriumSo, violations of H-W equilibrium conditions means the populations is undergoing evolutionThis can characterize the consequences of these violationsVI. Condition #1: Large Population•Non always true in natural populations•Some populations small, or fluctuate widely over time•If population small, random changes in gene frequency can occur, be-cause of statistical fluctuations in gene frequency•Genetic Drift: Changes in allele frequency from statistical fluctuations; not related to selective advantage/disadvantages•If f(A) = 1.0 or 0, then no further drift can occur. Population is fixed.•Bottleneck Effect: Extreme form of genetic drift. Large population crashes. Can be caused by an extreme event like a volcanic eruption. During crash, death is so widespread that allele frequencies among survivors might not represent the frequencies before the crash. Thefew survivors can bring back that particular allele. New population fromsurvivors has different allele