BIOL 152 1st Edition Lecture 4Outline of Last Lecture I. Evolution applied to a populationII. Measuring variationIII. Hardy-Weinberg PrincipleOutline of Current Lecture I. Hardy-Weinberg EquationII. Conditions of EvolutionIII. Small Population sizeCurrent LectureI. Hardy-Weinberg Equationp2 +2pq + q2Genotype Frequency P2=expected frequency of one of the homozygous genotypes2PQ= expected frequency of the heterozygous genotypeQ2 =expected frequency of the other homozygous genotypeAllele Frequency: Given the genotype frequencies you can determine the allele frequency.Example: Given the genotype frequency= 0.49, then p2 =0.49, p=0.7, the allele frequency for one of the homozygous genotypes is 0.7 and to find the allele frequency of the other homozygous genotype 1- 0.7= 0.3. Once you know the values of p and q you can determine the value for the frequency of the heterozygous genotype.II. Conditions of EvolutionMutations, nonrandom mating, natural selection, gene flow and small population size are all conditions for evolution. Mutations alter the allele, generate a new allele, or duplicate an allele. Nonrandom mating, changes genotype frequency because of interbreeding and an individual chooses a mate because of a specific phenotype i.e. height or size. Natural selection is a 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.consistent means of adaptive evolution; the selection increases the frequencies of certain alleles (those that increase fitness). Gene flow refers to the transfer of genes between populations through interbreeding. This changes the allele frequency and reduces differences overtime. III. Small population sizeWith a small population size, there is more variation among the individuals. Allele frequencies may be changed due to genetic drift or the chance of change in a gene pool. This may lead to fixation where the same allele is expressed generation after generation. The bottleneck effect explains how when a radical event occurs it can alter a population and result in a gene pool the does not represent the population. The founder effect is similar to the bottleneck effect except it accounts for a group of individuals who colonize an isolated island and do not represent the population from which they
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