EBIO 1220 1st Edition Lecture 3Outline of Last Lecture I. Darwinian Revolutiona. Science in the 1700sb. Charles Darwin Changes ThingsII. Evolution is FactIII. How Does Evolution Work?a. Natural Selectionb. Key Ingredients for Natural SelectionOutline of Current Lecture II. Where Does Evolution Come From?III. Mechanisms of Evolutionary Changea. Natural Selectionb. Genetic DrifIV. Evolution in the Wilda. Pocket MiceV. The Epigenetics Revolutiona. Horizontal Gene Transferb. HumansVI. Sexual Selection and Natural SelectionCurrent LectureII. Where Does Evolution Come From?a. Genetic Changesb. Mutations: random introduction of new allelesc. Recombination: new combinations of alleles due to sexual reproductionIV. Mechanisms of Evolutionary Changea. Natural Selectionb. Genetic Drifi. Random fixation or loss of alleles in small populations1. Small population of beetles- green killed @ higher frequency than brown by chance2. Bottleneck Effect: random surviving population3. Amish population of eastern Pennsylvaniaa. Founded by 200 colonistsThese 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. Relatively close inbreeding leads to Ellis van Creveld syndrome (recessive trait) which leads to polydactyly (extra fingers and toes)V. Evolution in the Wilda. Pocket Mice (sandy-colored) inhabit American SW desertb. Valley of Fire in New Mexico full of black volcanic rockc. Mice in need of camouflage against dark rockd. Predators: fox, coyote, owls, rattlesnakesi. All visual predatorse. Mice have evolved to match rock colori. Change in color driven by predators choosing light mice @ higher frequencyf. How did black mice come about?i. Mutations (random) caused darker pigmentation even before volcanic rock ii. Difference of 4 letters for certain geneiii. Mice with the mutation were more likely to survive/reproduceiv. Frequency of the allele for dark fur increases as a resultg. Example of Natural SelectionVI. Epigenetics Revolutiona. Heritable changes in gene expression that are NOT caused by changes in the DNAsequenceb. DNA methylation and repressor proteinsc. May be heritablei. Example: the fear of cherry blossoms…1. Mice that were taught to fear the smell of acetophenone had an altered patter of methylation on the odor receptor gene M712. Altered pattern of gene expression of same genotype 3. Gene’s DNA coding had not changed4. It did carry epigenetic marks that changed its behavior5. Caused the behavior to be “expressed more” in offspringd. Horizontal Gene Transferi. Wolbachiaii. Proteobacteriaiii. Infects insects in early developmentiv. Integrates its genome into host genomev. Its genome is expressed in infected host cellsvi. Transmitted through reproduction1. Male death/sterilization2. Males  females3. Parthenogenesis4. “Cytoplasmic Infertility”vii. Used to control disease- transmitting mosquitoese. Humansi. Flip side…ii. April 2010: Asians contain newly discovered enzyme porphyranaseiii. Allows digestion of seaweed (cellulose1. Probably transferred from bacteriaVII. Sexual Selection and Natural Selectiona. How do we explain showy traits like colorful coat, peacock feathers, huge antlers,etc?i. Adaptations to compete for matesb. Sexual Selection: traits predict mating successi. Antlers (fight off other males)ii. Humans (male ability to hunt, provide resources)c. Important Points about Natural and Sexual Selectioni. Don’t create variation; preserve or eliminate itii. Variants favored by natural selection depend on environmentiii. Selection doesn’t have any “long-term goals”iv. Traits are favored if they increase survival and reproductive outputv. Natural Selection ≠ Evolution1. Evolution is fact2. Natural selection is a theory explaining