BIOL 112 - JohnsonExam 1 Study GuideChapter 22What is the definition of Evolution? What are some common misconceptions about evolutionDescribe Darwin’s BackgroundDarwin’s BackgroundHMS Beagle 1831-1836 Darwin paid specific attention to geographical distribution and adaptations of animals across the globe.Studied local geographyPrinciple of Uniformitarianism( Lyell) convinced Darwin that the earth is millions of years old.Developed his theory in 1844, but went public in 1858Some ideas were shared by others, for example Darwin and Alfred Wallace published their original works together.On The Origin Of Species was published in 1859Knew Lemarckian evolution was wrong, but agreed that adaptations are key to evolutionDarwin’s Theory Of EvolutionAll present life is related through “descent with modification” with a common ancestor in the pastNow referred to as evolutionNatural Selection: The mechanism for evolutionDarwin’s Observations1: All creatures seem to create more offspring that the environment can support (Think: Malthus)Most populations are relatively stableBased off /agrees with Malthus’ observations that the potential for human populations is exponential and resources of the modern world cannot sustain2: There is a heritable individual variation within a speciesIndividuals with a trait that helps them survive and reproduce will have more offspring than other “less fit” individuals. OR There is unequal reproductive success among individuals of a populationHeritable, favorable traits or adaptations accumulate over time, and may ultimately lead to a new species based on different environments and natural consequencesUnfavorable variations are lost over time*Natural selection results in different adaptations in different environments.Describe the Evidence Used to Support Darwin’s TheoryDirect Observation of Natural SelectionEx: Soap-berry Bugs and Antibiotic ResistanceFossil RecordOlder rocks lay below newer rocksExtinct SpeciesTransition FormsHomologyHomologous StructuresVestigial StructuresDevelopmental HomologiesMolecular and Cellular HomologiesConvergenceAnalogous StructuresNatural Selection will select similar adaptations across different environments and lineagesBiogeographyChapter 23Describe the relationship between Mendel’s Genetics and Darwin’s Evolutionary theoryUnderstand the basis for the biological definition of a Species and a PopulationWhat level or organization does Natural Selection act on? Evolution?To Prove Natural SelectionIs a trait heritable?Is the trait an advantage over other individuals?Genetic Variation – Be familiar with the following topics, these will not be tested discretelyDiscrete VariationGenotype determines the phenotypeA single gene locus with 2 or more allelesIncludes: co-dominance, complete/incomplete dominanceQuantitative VariationPhenotype is produced via additive effects of two or more genesGenerally involved two different chromosomes or lociDefine: Gene Pool; MicroevolutionDefine and explain the following terms associated with Hardy-WeinbergGenotypic Frequency%AA, %Aa, %aaTypically seen by the phenotypeAllelic Frequency%A and %aList the Hardy Weinberg Requirements / Assumptions (5)Explain the process of Genetic drift, name and describe the two key mechanisms, and explain how both affect variation and diversity within a populationExplain the process of Gene Flow, and understand the resultsForms of Natural SelectionBe able to give an example of each, and understand what happens to the average phenotypeDirectional SelectionDisruptive SelectionStabilizing SelectionSexual SelectionHow does sexual selection lead to sexual dimorphism?How is genetic variation maintained in the population?Through DiploidyWhat is heterozygote advantage?How are recessive alleles maintain in the population?Through Disruptive SelectionWhat happens if, over time, disruptive selection continues?Through Frequency Dependent SelectionHow do allelic frequencies act in this case?Explain the limits of Natural Selection.Chapter 24What are reproductive barriers, and how do they contribute to maintaining biological species?Pre-Zygotic Barriers: Prevent fertilization and mating from occurring (pre-baby)Habitat / ecological isolationTemporal isolationBehavioral isolationMechanical isolationGametic isolationPost-Zygotic Barriers: act after the zygote is formed, but not necessarily after birth of hybridReduced Hybrid ViabilityReduced Hybrid FertilityHybrid BreakdownWhat are some problems with the biological species concept?Fossils, Asexual species, sometimes hybrids happenHow do new species form?Speciation increases the diversity of lifeWhat are the requirements for speciation to occur?One population must becomes genetically isolatedIt must genetically diverge from the other populationBiological reproductive barriers must ariseSpeciation may occur with or without geographic isolationDefine Allopatric Speciation, paying close attention to the two mechanism discusses in class, and specifically how it leads to the creation of new speciesAllopatry = a physical barrier forms and separates members of the same population. Usually results in some form of evolutionary change often creating new speciesWhat happens if reproductive barriers do not arise from the separation?What is the evidence for allopatric speciation?EX: mosquitofish – body shape influences mate choiceEX: fruit flies adapted to different foods and diverged enough to prefer similarly adapted mates.EX: Sister species of shrimp live across the panama land bridgeDefine Hybrid Zones, the three different types, and what happens to the pre-zygotic barriers in each caseReinforcementFusionStabilityWhat is sympatric speciation? Why is it so much more common in plants?Isolation by HabitatIsolated behaviorally by sexual selectionIsolation by polyploidyWhat is polyploidy?Define autpolyploidyPolyploidy hybrids of two different speciesSympatric speciation in animals most likely occurs through different kinds of habitat isolation where no real physical barriers are presentChapter 25Define Macroevolution. How is it different from other types of evolution discussed in class?Explain lineage direction in terms of MacroevolutionEach lineage group began from one speciesSubject to various amounts of microevolution, followed by more speciation and/or extinction eventsWhat is Adaptive Radiation? How does it lead to diversity in terms of species?Many species with diverse adaptations descend from one common ancestor