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PRINCIPLES OF EVOLUTIONEVOLUTIONSlide 3EVIDENCE THAT SPECIES ARE RELATEDSlide 5EVIDENCE THAT SPECIES ARE RELATED: HOMOLOGIESSlide 7Slide 8Slide 9GENETIC HOMOLOGIESEVIDENCE THAT SPECIES CHANGE THROUGH TIMESlide 12Slide 13EXTINCT & TRANSITIONAL SPECIESSlide 15THEORY OF EVOLUTION BY NATURAL SELECTIONTHEORY OF EVOLUTION BY NATURAL SELECTIONTHEORY OF EVOLUTION BY NATURAL SELECTIONTHEORY OF EVOLUTION BY NATURAL SELECTIONEXPERIMENTAL EVIDENCE OF NATURAL SELECTIONSlide 21EXPERIMENTAL EVIDENCE OF NATURAL SELECTIONSlide 23Slide 24Slide 25MECHANISMS OF EVOLUTIONARY CHANGEMECHANISMS OF EVOLUTIONMECHANISMS OF EVOLUTION: MUTATIONMECHANISMS OF EVOLUTION: GENETIC DRIFTGENETIC DRIFTMECHANISMS OF EVOLUTION: MIGRATIONMECHANISMS OF EVOLUTION: NATURAL SELECTIONMECHANISMS OF EVOLUTION: NATURAL SELECTIONSlide 34Slide 35Slide 36NATURAL SELECTIONMECHANISMS OF EVOLUTION: SEXUAL SELECTIONSlide 39Slide 40MECHANISMS OF EVOLUTION: SEXUAL SELECTIONSlide 42Slide 43Slide 44PRINCIPLES OF EVOLUTIONEVOLUTION•EVOLUTION:EVOLUTION• Darwin used phrase “descent with modification” to describe evolutionEVIDENCE THAT SPECIES ARE RELATED•Darwin’s Observation:•Darwin’s Conclusion: Galapagos IslandsGALAPAGOS MOCKINGBIRDS DIFFER ONLY SLIGHTLY IN SIZE, SHAPE AND COLORATIONNesomimus macdonaldiN. melanotisN. parvulusN. trifasciatusDarwin’s Conclusion: Species are similar because they share a common ancestorN. macdonaldiN. melanotisN. parvulusN. trifasciatusDarwin Observed: Species from neighboring islands look similarEVIDENCE THAT SPECIES ARE RELATED: HOMOLOGIESHomologies:•Similarities across species with common ancestry–Structural–Developmental–GeneticStructural Homology: Turtle Human HorseBird BatSealHumerusRadius and ulnaCarpalsMetacarpalsPhalangesSTRUCTURAL HOMOLOGIESDevelopmental Homology:Gill pouchTailBoth chick and human embryo have gillpouches and tailsChick HumanDEVELOPMENTAL HOMOLOGIESGENETIC HOMOLOGIESGenetic Homology:GENETIC HOMOLOGIES•The greater the degree of genetic similarity between two organisms, the more closely related they are assumed to beEVIDENCE THAT SPECIES CHANGE THROUGH TIMEImportance of the Fossil Record:•Law of Succession•Evidence of extinctions•Transitional species•Vestigial traitsEVIDENCE THAT SPECIES CHANGE THROUGH TIMELaw of Succession:•Observation:•Conclusions:EVIDENCE THAT SPECIES CHANGE THROUGH TIMEEvidence of Species Extinctions From Fossil Record:–If one species gradually evolves into another, transitional species should be presentEXTINCT & TRANSITIONAL SPECIES•Recently discovered fossils of ancient (extinct) whales indicate that whales evolved from terrestrial ancestorsEVIDENCE THAT SPECIES CHANGE THROUGH TIME•Vestigial Traits:THEORY OF EVOLUTION BY NATURAL SELECTIONDarwin’s observationsallowed him to formulate a hypothesis regarding the mechanism of evolutionTHEORY OF EVOLUTION BY NATURAL SELECTIONNatural Selection: Proposed by Darwin and WallaceTHEORY OF EVOLUTION BY NATURAL SELECTIONNatural Selection’s Four Postulates:1. Individuals in a population vary in traits they possess2. Some of these variable traits are heritable 3. Not all offspring survive to reproduce4. Offspring that carry certain traits are more likely to survive to reproduce or will reproduce moreTHEORY OF EVOLUTION BY NATURAL SELECTIONSome Terminology:–Darwinian Fitness–AdaptationEXPERIMENTAL EVIDENCE OF NATURAL SELECTIONCase Study: •Rise in Resistance to Antibiotics in Tuberculosis BacteriaIncidence of TB infections in 1997 (per 100,000 people)Less than 1010-2425-4950-99100-250More than 250EXPERIMENTAL EVIDENCE OF NATURAL SELECTIONCase Study: The Rise in Resistance to Antibiotics in TB–Young HIV-positive man admitted to hospital with TB(1980s)–Patient treated for 40 weeks with antibiotics (rifampin)–After 40 weeks: culture shows no signs of TB;chest x-ray clear–Two months later: patient readmitted with TB–Patient treated with series of antibiotics (including rifampin)–Patient dies 10 days laterEXPERIMENTAL EVIDENCE OF NATURAL SELECTIONApply Four Postulates of Natural Selection To Case Study:1. Variation In the Population of TB Existed:1. Variation was Heritable:2. Only Subset of Bacteria Survived to ReproductionEXPERIMENTAL EVIDENCE OF NATURAL SELECTIONApply Four Postulates of Natural Selection To Case Study:4. Subset of Pop. Survived Better and Reproduced More1000-year-old mummyfrom PeruThe nodules in the lung tissueindicate that the woman diedfrom tuberculosisMECHANISMS OF EVOLUTIONARY CHANGEEvolution Redefined:MECHANISMS OF EVOLUTIONMechanisms that Change Allele Frequencies in Populations•Mutation•Migration•Genetic Drift•Natural SelectionMECHANISMS OF EVOLUTION: MUTATION1. Mutation:MECHANISMS OF EVOLUTION: GENETIC DRIFT 2. Genetic Drift:GENETIC DRIFTMECHANISMS OF EVOLUTION: MIGRATION3. Migration:MECHANISMS OF EVOLUTION: NATURAL SELECTION4. Natural Selection:Note: Mutation, genetic drift, migration do NOT increase fitness and are NOT adaptiveMECHANISMS OF EVOLUTION: NATURAL SELECTIONThree Types of Natural Selection :1. Directional Selection 2. Stabilizing Selection 3. Disruptive SelectionAfter selectionDuring selectionNumber of individualsBefore selectionNormal distributionValue of a traitDIRECTIONAL SELECTIONNormal distributionHigh fitnessValue of a traitNumber of individualsAfter selectionDuring selectionBefore selectionSTABILIZING SELECTIONValue of a traitLow fitnessNormal distributionBefore selectionDuring selectionAfter selectionNumber of individualsDISRUPTIVE SELECTIONNATURAL SELECTIONMECHANISMS OF EVOLUTION: SEXUAL SELECTIONSexual Selection:–A type of natural selection "[Sexual Selection] depends, not on a struggle for existence, but on a struggle between the males for possession of the females; the result is not death to the unsuccessful competitor, but few or no offspring." –Charles Darwin, Origin of Species (1859)MECHANISMS OF EVOLUTION: SEXUAL SELECTIONSexual Selection:•Effects genes involved in mate choice and aspects of reproductionMECHANISMS OF EVOLUTION: SEXUAL SELECTIONHercules BeatleMECHANISMS OF EVOLUTION: SEXUAL SELECTIONSexual Selection:•In most sexually reproducing species, females invest more in offspring than malesMECHANISMS OF EVOLUTION: SEXUAL SELECTIONSexual Selection:•Females produce relatively few eggs/young over lifetime•Males produce large quantities of sperm; can father almost limitless numbers of offspringMECHANISMS OF EVOLUTION: SEXUAL


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UMBC BIOL 100 - PRINCIPLES OF EVOLUTION

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