BS 162 1nd Edition Lecture 10 Current Lecture Mutant Allele creates new source of variation Mutation the source of genetic variation and is random How does genetic variation occur 1 Meiosis independent assortment and crossing over 2 Mutation 3 Sexual reproduction Asexual reproduction extremely low genetic diversity Sexual reproduction greater genetic diversity Is variation good Heterozygous advantage and lack of variation Measuring Evolution Evolution change in allele frequencies over time can result in large changes 3 Conditions for Evolution 1 Individuals vary in their traits 2 Some of these variations are heritable 3 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 chance Founder 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 population Gene flow genetic exchange with other population reduces genetic differences America The Melting Pot The Atlantic Ocean was a barrier to gene flow between residents of North America Europe etc Genetic Drif within one population usually decreases genetic variation Gene Flow within two different populations Evolution by Natural Selection 1 Individuals vary in their traits 2 Some of these variations are heritable 3 Some individuals survive and reproduce better than others 4 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 population