30 JANUARY 201423_BIO130_0130141/30/2014Bio 130 TR 12:40-1:55p Lecture 7- Turn in description of sexual selection.- Cassie is giving a guest lecture on Tuesday, bring your clicker!- Big Quiz average: 40/50, 80%- Exam will be harder, but you can replace big quiz grade with that averageEvolutionary Processes – processes that can change allele frequencies over time1. Natural Selection2. Genetic Drif3. Gene Flow4. MutationObjectives:- Explain how sexual selection differs from normal natural selection- Explain how any evolutionary process results in evolution. What is it? Effect on fitness/genetic variation?- Explain how levels of gene flow affects a population’s evolutionSpecies > Population > IndividualPopulation: A group of individuals from the same species that live in the same area and interact. 1. Natural Selection: Increases fitness and results in adaptation, can increase or decrease genetic variationa. Sexual selection - selection due to success in courtship/obtaining matesFemale choice & Male-male competitionVideo Homework Review: Phenotypes – Song, color, plumage, ornamental feathers, behavior, dance. Mutations cause natural selection, and females prefer brighter males. Females are the more choosy gender because males are less involved in parental care, but carrying offspring for a female is a resource-taxing experience. There is male to male competition that also influences sexual selection. There is a limit to how showy males can be, because they still have to be able to survive, get food and hide from predators.2. Genetic Drif: Allele frequencies change/fluctuate due to chance (random process) e.g. random mortality due to flooding, human interaction.There is no way to predict the affect that drif will have the population. Chance events add up very quickly in small populations, while have less affect in a large population. The effect of genetic drif is that it reduces genetic variation. The founder effect is when a new population randomly has different allele frequencies than the original population, because it is a small sample of the population. E.g. iguanas populating an island, elephant seals surviving a human slaughter, and cheetah populations having a low genetic diversity. Genetic drif does not consistently effect fitness in a particular direction, because it is random.3. Gene Flow: Is a fancy word for migration. Gene flow = migration Do not make this hard, two words, same meaning. E.g. Two populations mixing. High gene flow makes populations more30 JANUARY 2014similar. Real world example: Great tits from the Netherlands.High gene flow: When it’s good: new alleles introduced to a population with low