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BIOL 2061 1st Edition Lecture 6 Outline of Last Lecture I. What Darwin didn’t knowII. Evidence of evolutionIII. Phenotype, genotype, homozygous, heterozygousIV. Genetic diversityV. Hardy-Weinburg EquilibriumOutline of Current Lecture I. Review Hardy-Weinburg EquilibriumII. Darwinian fitnessIII. Natural SelectionIV. Natural Selection patternsCurrent LectureI. Hardy-Weinburg Equilibriuma. Equilibrium- a null hypothesis that’s saying evolution is not occurringb. HW Equilibrium is:i. No natural selectionii. No mutationiii. Random matingiv. No migrationv. A large population sizeII. Darwinian Fitness-a. A measure of reproductive successThese 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.b. Relative likelihood that a genotype will contribute to the gene pool of the next generationIII. Natural selectiona. 4 requirements of natural selectioni. Variationii. Heritabilityiii. Selection pressureiv. TimeIII. Natural Selection Patternsi. Directional selection- a. Ex. A population of mice has some individual with light fur and dark fur, there is somesolidified black lava flow and the mice with the light fur can be seen easier than the dark fur mice on the lava flow. (This favors an individual at one extreme of a phenotypic distribution, by favoring the dark fur mouse)ii. Stabilizing Selection-a. Ex. Human babies who are very light weight have a higher risk of catching an infection, whereas a baby that is heavier is harder to give birth to through the pelvis. (this favors an intermediate phenotype, it works as a interval, don’t want too much and don’t want too little, want just in the middle)iii. Disruptive Selection-a. Ex. Bentgrass (a type of grass) grows in meadows. In an area of Wales, mining spills have contaminated the soil in isolated patches of meadows. Mutant strains of bentgrass that can tolerate heavy metals are dominant in those patches. If the mutant and normal strains interbreed, the offspring can’t live on the contaminated patches or the pristine part of the meadow. (This favors two phenotypes because in areas the non-mutant can survive and in areas the mutant can survive also).iv. Balancing Selection- a. Ex. There are red berries and blue berries, when the red berries are common birds eat them more and the blue berries increase in population. But when the blue berries are more common, the birds like to eat them more frequently. (the


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