BCOR 12 1st Edition Lecture 3 Outline of Last Lecture I. Evidence for EvolutionII. Evolution: Process and a patternIII. Darwin’s Main Observations and inferencesIV. Important Points about Natural SelectionOutline of Current Lecture I. Microevolution mechanismsII. Genotypes and allele frequenciesIII. The Hardy-Weinberg PrincipleIV. HW assumptions Current LectureThe Evolution of Populations – Chapter 23- Natural selection and evolution are NOT synonyms- Natural selection – directed change (works on the INDIVIDUAL level)Microevolution – a change in allele frequencies in a population over time (at the molecular level)The mechanisms that cause evolutionary change:I. Natural selection – directed change II. Gene flow – random change due to migration of new individuals and alleles into the populationIII. Genetic drif – random change; the random fluctuations from one generation to the nexta. Founder effect b. Bottleneck effect (go into more detail in next lecture)IV. Mutation – random change in the nucleotide sequence of an organism’s DNA (individual level)- Smallest unit that evolution can occur is population; we determine frequency of alleles by taking in consideration of whole populationThese 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.Population – group of individuals of the same species that can interbreed and produce fertile, viable offspringCommunity – populations living among other populations- Evolution at the molecular level involves changes in the gene pool of a population- Gene pool – all of the alleles present in all individuals in a population- Allele – alternative form of a gene at the same locus (location in a DNA sequence)Problem: What is the allele frequencies of p in a population of 100 flowers with the following genotypes: 50 pp, 25 Pp, 25 PP. Alleles # of P # of pPP 50 50 0Pp 50 25 25pp 100 0 100Total: 75 125*the number of alleles is double the amount of individuals with the certain genotype for there are two alleles presentFrequency of p = (Total # of p alleles in population)/(total alleles in population)Frequency of p = 125/200 = .625 or 62.5%Hardy-Weinberg Equation – can be used to test whether or not a population is evolvingP2+pq+q2=1p = dominant trait frequencyq = recessive trait frequencyp + q = 1- Allele frequencies = genotype frequenciesHardy Weinberg Equation Five AssumptionsI. NO mutationsII. Random Mating (no sexual selection)III. NO natural selectionIV. Extremely large population size (no genetic drif)V. NO gene flow- If any of these assumptions are not followed, then the Hardy-Weinberg will not apply and the population will be evolving- If a population follows all of the assumptions of the Hardy-Weinberg then the populationis NOT evolving and the allele frequencies will remain constant over