Evolution: Lamarck Evolution: Change over time Evolution: Change over time Lamarck Lamarck Use /...

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Evolution: Lamarck Evolution: Lamarck Evolution: Evolution: Change over Change over time time Lamarck Lamarck Use / disuse Use / disuse Theory of Theory of inheritance inheritance of ACQUIRED of ACQUIRED traits traits

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Transcript of Evolution: Lamarck Evolution: Change over time Evolution: Change over time Lamarck Lamarck Use /...

  • Evolution: Lamarck Evolution: Change over timeLamarckUse / disuseTheory of inheritance of ACQUIRED traits

  • Evolution: DarwinDarwins Voyage on the HMS Beagle

  • Evolution: Darwin / Natural SelectionDarwin observed that organisms produce more offspring than the environment can supportorganisms VARY in many traitsthese variations can be inheritedSome traits better fit for the environment than other traits

  • Evolution: Darwin / Natural SelectionDarwin = individuals best suited for a particular environment are more likely to survive AND reproduce than those less well adaptedDarwin saw natural selection as basic mechanism of evolutionAs a result, proportion of individuals with favorable characteristics increasesPOPULATIONS (not individuals) gradually change in allele frequency in response to the environment

  • Evolution: Natural Selection

  • Evolution: Natural Selection vs Artificial SelectionArtificial Selection- man creates pressure

  • Four Evidence of EvolutionBiogeographyFossilsComparative AnatomyHomologous StructuresComparative EmbryologyMolecular BiologyDNA / Proteins / Amino Acid sequences

  • Evidence for Evolution: FossilsTransitional Fossils

  • Evidence for Evolution: Comparative AnatomyHomologous Structures:Similar structure (what does that suggest); different function (what does that suggest)

  • Evidence For Evolution: Molecular Biology

  • Convergent vs Divergent EvolutionAnalogous structure: similar function, different structureEx. Wing of insect and birdConvergent EvolutionDivergent Evolution Homologous Structures

  • Microevolution vs MacroevolutionMicro = small changes, still same speciesMacro = speciationMicroevolution = change in allele frequencies in a gene pool

  • Microevolution: Gene PoolGene pool = total numbers of allele in a populationAllele frequency = % of that specific allele in gene pool

  • Hardy Weinberg EquilibriumHardy-Weinberg equilibrium: even if alleles are shuffled in the next generation (new genotypes appear) allele frequency / proportions in the gene pool stay the same from generation to generation

  • Hardy-Weinberg EquilibriumLarge populationIsolated populationNo genetic mutationsRandom MatingNo Natural Selection

  • Hardy-Weinberg EquilibriumALLELE FREQUENCYp = A freqq = a freq

    p + q = 1GENOTYPE FREQUENCYp2 = AA freq2pq = Aa freqq2 = aa freq

    p2 + 2pq + q2 = 1

  • Hardy-Weinberg: Genotype & Allele Frequencies

  • Hardy-Weinberg: Genotype & Allele Frequencies

  • Hardy-Weinberg Practice ProblemIn a certain population, the frequency of homozygous curly haired (HH) is 64%. What percentage of the population has curly hair?Given: p2 = .64 Find: p2 + 2pqp = .8 q = .2 2(.8)(.2) = .32 or 32%64% (HH) + 32% (Hh) = 96% curly haired

  • 5 Causes of MicroevolutionPopulation becomes SMALL due to chance: GENETIC DRIFTPopulation is NOT isolated: GENE FLOWMutations occurMating is NOT randomNatural selection exists: some traits are better fit than others

  • Causes of Microevolution:Genetic Drift: Gene pool changing due to CHANCEBOTTLENECK EFFECTPop shrinks due to natural disasterFOUNDER EFFECTColony leaves

  • Gene Flow & Non Random MatingGene Flow NONrandom Mating

  • Causes of Microevolution:Natural Selection3 outcomes of Natural Selection:Stabilizing, Directional, Disruptive/Diversifying

  • Macroevolution: SpeciationSpeciation the creation of new speciesSpecies:a population or group of populations whose members can interbreed and produce fertile offspring

  • Reproductive BarriersReproductive barriers prevents different species from mating with each other:Mating times / seasons differentDifferent habitatDifferent mating behavior so little attraction between species

  • Reproductive Barrier:Geographic BarrierAllopatric Speciation: When a population is cut off from its parent population, species evolution may occurgene pool is changed by natural selection, genetic drift, or mutation

  • Geographic Barrier:Adaptive RadiationAdaptive radiation (ex of allopatric speciation) on an island chain from one main species there are multiple different species evolving