BIOL 2061 1st Edition Lecture 7Outline of Last Lecture I. Review Hardy-Weinburg EquilibriumII. Darwinian fitnessIII. Natural SelectionIV. Natural Selection patternsOutline of Current Lecture I. Sexual selectionII. MutationIII. Random mating/ non- randomIV. Migration/gene flowV. Large population sizeCurrent LectureI. Sexual selectiona. Is a form of NATURAL SELECTIONb. Directed at certain traits of sexually reproducing species that make it more likely for individuals to find or choose a mate and/or engage in successful matingc. Affects the male characteristics more than femalei. Due to the female choosinessd. Intrasexual selection- (within or between)i. Between members of the same sexii. Males directly compete for mating opportunities or territoriesiii. Ex. Horns, antlers, enlarged clawse. Intersexual selection –(attracting females)i. Between members of the opposite sexii. Female choiceiii. Often results on showy characteristics for malesiv. Cryptic female choiceThese 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.1. Genital tract of egg selects against genetically related sperm a. Prevents inbreedingf. Sexual selection explains traits that decrease survival but increase reproductive successi. Ex. Male peacocks- have long bright long tails. The long tails make them easier to catch by predators, but the ladies like the look so they reproduce moreII. Mutationa. Mutations aren’t rareb. Mutations occur all the timec. Some have no effect, some are deleterious, some have a advantaged. Common misconception is that all mutations are bade. *** mutation is the only way for new alleles to be created***III. Random/ non-random matinga. One of the conditions required to establish HWE is random matingi. Individuals choose their mate irrespective of their genotypes and phenotypes.b. Non-random matingi. Assortative mating- mating with and individual with similar phenotypes1. This increases the proportion of homozygotesii. Disassortative mating- mating with an individual with dissimilar phenotypes.1. Favors heterozygotesiii. Inbreeding- mating with an individual with a similar genetic make-up.1. May have a negative consequence with regard to recessive alleles if homozygous traits reduce fitness2. Decreases the heterozygous alleles completely3. ex. Aa, Aa, Aa, Aa AA, AA, aa, aaIV. Migration/ Gene flowa. Both mean the same thingb. Gene flow occurs when individuals migrate between populations having differentallele frequencies.c. Gene flow INCREASES genetic diversity in a populationd. Gene flow DECREASES allele frequencies in two populations ( as they mix they become more alike)V. Large Population Sizea. Important because “genetic drift” will more likely occur in SMALL populationsb. Genetic drift- changes in allele frequency due purely by chancec. random events are unrelated to fitnessd. favors a loss or fixation of an allele ( as one allele increases (fixed) the other alleledecreases (lost).)i. loss= 0% of alleleii. fixation= 100% of allelee. genetic drift occurs more often in small