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