Môn Sinh học - Chapter 26: Phylogeny and the tree of life

Warm-UpContrast adaptive radiation vs. convergent evolution? Give an example of each.What is the correct sequence from the most comprehensive to least comprehensive taxon?In a population of 500 rabbits, 320 are homozygous dominant for brown coat color (BB), 160 are heterozygous (Bb), and 20 are homozygous white (bb).What are the frequencies of the alleles (B and b)?What are the frequencies of the different genotypes (BB, Bb, and bb)?Chapter 26Phylogeny and the Tree of LifeWhat you need to know:The taxonomic categories and how they indicate relatedness.How systematics is used to develop phylogenetic trees.The three domains of life including their similarities and their differences.SystematicsTaxonomy(classification)Phylogenetics(evolutionary history)Systematics: classifying organisms and determining their evolutionary relationshipsTools used to determine evolutionary relationships:FossilsMorphology (homologous structures)Molecular evidence (DNA, amino acids)Animals and fungi are more closely related than either is to plants.Who is more closely related?Taxonomy: science of classifying and naming organismsBinomial nomenclature (Genus species)Naming system developed by Carolus Linnaeus.REMEMBER!!Dear King Philip Came Over For Good SpaghettiDear King Philip Crossed Over Five Great SeasDear King Philip Came Over From Germany StonedYour own???Phylogenetic TreeBranching diagram that shows evolutionary history of a group of organismsActivity: Constructing a Cookie Phylogenetic TreeLiving (extant) speciesCommon ancestor(fossil)Extant speciesCommonancestorExample of a Cookie TreeClade = group of species that includes an ancestral species + all descendentsShared derived characteristics are used to construct cladogramsCladogram: diagram that depicts patterns of shared characteristics among taxaTurtleLeopardHairAmniotic eggFour walking legsHinged jawsVertebral columnSalamanderTunaLampreyLancelet (outgroup)CladogramMonophyletic, paraphyletic, and polyphyletic groupsConstructing a phylogenetic treeA 0 indicates a character is absent; a 1 indicates that a character is present.Branch lengths can represent genetic changeBranch lengths can indicate timeDraw a phylogenetic tree based on the data below. Draw hatch marks on the tree to indicate the origin(s) of each of the 6 characters.Answer:Unrooted treeCircular (rooted) treeRooted treeVarious tree layoutsPrinciple of maximum parsimony: use simplest explanation (fewest DNA changes) for tree – “keep it simple” Molecular clocks: some regions of DNA appear to evolve at constant ratesEstimate date of past evolutionary eventsEg. Origin of HIV infection in humans= 1930’sTree of Life3 Domains: Bacteria, Archaea, EukaryaSYSTEMATICSBiological diversitytaxonomyIdentification of speciesbinomialGenus, speciesDKPCOFGSphylogenyclassificationcladisticsHomologoussimilaritiesfossilsmolecularmorphologyfocuses on