BIOL 152 1st Edition Lecture 3 Outline of Last Lecture I Mutation causes and consequences II Evolution III Natural selection Outline of Current Lecture I Evolution applied to a population II Measuring variation III Hardy Weinberg Principle Current Lecture I Evolution applied to a population A 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 variation Allele 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 Principle This 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 random
View Full Document
Unlocking...