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Unformatted text preview: 4/3/09 1 Phylogeny and the Tree of Life Australopithecus Homo sapiens neanderthalensis Homo robustus Homo habilis The common ancestor of these two species did not have thorns. The thorns are: A. monophyletic B. paraphyletic C. polyphyletic D. analogous E. homologous The common ancestor of these two species did not have thorns. The thorns are: A. monophyletic B. paraphyletic C. polyphyletic D. analogous E. homologous * Phylogenetic trees • ideally reFect evolutionary relationships • branch points represent the most recent common ancestor • sister taxa share an immediate common ancestor (Canidea are sister to …) • ranks above level of species are subjective. • perhaps they should be abandoned A clade is a monophyletic group Cladistics is the hierarchical classi¡cation of species based on evolutionary relationships. 4/3/09 2 Fish are paraphyletic Teleost fsh are monophyletic • Using derived characters to derive phylogeny. The outgroup anchors the analysis o¡ the species under consideration. • Since all o¡ the ingroup members have backbones, they have common ancestor with a backbone and ¡orm a clade (the vertebrates)....
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