Biol 3350 1st Edition Lecture 22Outline of Last Lecture I. TaxonomyII. SystematicsIII. PheneticsIV. Types of distance measuresV. CladisticsVI. Terminology of CladogramsVII. Parsimony AnalysisOutline of Current Lecture I. Phenetics vs. CladisticsII. Issues in Phylogenetic ReconstructionIII. Why use DNA for molecular phylogenetics?IV. PhylogeographyV. How did the Seychelles Tiger Chameleon cross the ocean?Current LectureI. Phenetics vs. Cladisticsa. Phenetics:i. Dendogram or phenogramii. Distance: Euclidean or geneticiii. Always unrootediv. Does not make inferences about ancestryb. Cladistics:i. Phylogent or cladogramii. Evolutionary steps or mutational changesiii. Unrooted unless you have the true ancestoriv. Makes inferences about ancestryII. Issues in Phylogenetic Reconstructiona. Character choicei. Need to be specific with choosing a good character b/c fingers/nails are easily mistaken for claws so claws may not be a good character to chooseb. Character scoringc. Character transformationi. Need to know if something was secondarily lost or evolved from parallel evolutionThese 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.d. Outgroup choicei. What to pick a species for the outgroup that has more of the ancestral traitsIII. Why use DNA for molecular phylogenetics?a. Access to many charactersb. Character states are unambiguousc. Some genes evolve very rapidlyd. Molecular “clock” can be used to date divergences between taxaIV. Phylogeographya. Uses phylogenies to understand the biogeographic distribution of speciesi. Geographic barriers that promote speciationii. Cryptic speciesiii. Origins of new speciesV. How did the Seychelles Tiger Chameleon cross the ocean?a. Vicariance – evolved before Seychelles were separated from Africa; carried along with the landmassesi. Vicariance is considered to be the primary driver of speciation as the landmasses move awayb. Dispersal – carried to the Seychelles by ocean currents on floating vegetationi. Evidence showed that this was the more likely hypothesisii. The most closely related species are in South Africaiii. Last common ancestor occurred well after break up with continents and
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