BS 162 1nd Edition Lecture 10Current LectureMutant Allele = creates new source of variationMutation: the source of genetic variation and is randomHow does genetic variation occur?1) Meiosis (independent assortment and crossing over)2) Mutation3) Sexual reproductionAsexual reproduction = extremely low genetic diversitySexual reproduction = greater genetic diversityIs variation good?  Heterozygous advantage and lack of variationMeasuring EvolutionEvolution: change in allele frequencies over time…can result in large changes3 Conditions for Evolution1) Individuals vary in their traits2) Some of these variations are heritable3) Some individuals survive and reproduce better than others 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.Genetic Drif- It causes allele frequencies to drift up and down randomly over time- Genetic drift is most pronounced in a small population- Over time, genetic drift can lead to the random loss or fixation of alleles. When random loss or fixation occurs, genetic variation in the population declines- It’s a change in the gene pool of a population due to chanceFounder Effect- Occurs when a new colony is started by a few members of the original population- This small population size means that the colony may have reduced genetic variation from the original populationGene flow = genetic exchange with other population  reduces genetic differencesAmerica: The Melting PotThe Atlantic Ocean was a barrier to gene flow between residents of North America, Europe, etcGenetic Drif: within one population  usually decreases genetic variationGene Flow: within two different populationsEvolution by Natural Selection1) Individuals vary in their traits2) Some of these variations are heritable3) Some individuals survive and reproduce better than others4) Individuals with certain traits are more likely to produce the greatest number of offspring in a given environment. The individuals with those traits are “naturally selected”Fitness: ability of an organism to survive and reproduce better than other individuals. Look at # of offspring and how many survive. Selective Agent: the thing that eliminates an allele from a