BIOL 152 1st Edition Lecture 3 Outline of Last Lecture I. Mutation causes and consequences II. EvolutionIII. Natural selectionOutline of Current Lecture I. Evolution applied to a populationII. Measuring variationIII. Hardy-Weinberg PrincipleCurrent LectureI. Evolution applied to a populationA population is localized group of individuals in a species that are capable of interbreeding. A genome is the total genetic complement of individual organisms; the two types of genomes are nuclear genomes and mitochondrial genomes. The gene pool is all the allele at all gene loci in all individuals of a population. Evolution in regards to population refers to the changes in frequencies of genotypes or alleles. Natural selection changes the gene pool of a population because some genes are eliminated and not expressed. Natural selection affects an individual but the population evolves. Example: a cricket population has a variation of crickets with a file, and another variation with no file otherwise known as mute crickets. In normal conditions, the cricket with the file is able to make noise and attract a mate, therefore increasing its chance of passing on its genes. The mute cricket is unable to make noise and attract a mate reducing its chances of passing on its genes. However if the conditions are changed and a parasitic fly is introduced to the population, the opposite is likely to occur because the fly hears the noisy crickets and plants its larva inside them, reducing the noisy cricket population and subsequently increasing the mute population. In this example natural selection played in favor of the mute cricket individuals but the cricket population evolved. II. Measuring variationAllele frequencies: An example of a flower population with 500 individuals, 160 are pink (Aa), 320 are red (AA) and 20 are white (aa). 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.To determine the frequency of A: (320*2) +160= 800/(500*2)= 0.80*100= 80% To determine the frequency of a: (20*2)+ 160=200/(500*2) =0.20*100=20%Genotype frequencies: Using the same example as the allele frequencies.Red: 320/ 500 = 0.64 * 100 = 64%Pink: 160/500 =0.32 * 100 =32%White: 20/500 =0.04 *100 =4% III. Hardy-Weinberg PrincipleThis principle states that frequencies of alleles and genotype in a population’s gene pool remain constant from generation to generation. Hardy-Weinberg Equilibrium is maintained by the following conditions; no natural selection, no gene flow, no mutations, large population size, and mating is
View Full Document