BIOL 103 Lecture Notes - Dna Barcoding, Monophyly, Paraphyly
Document Summary
Elements and terms used to describe phylogenetic trees: Node a represents the common ancestor to all taxa in the tree. Paraphyletic taxon: common ancestor but not all descendants. Polyphyletic taxon: groups of species with different common ancestors. The goal of taxonomy is to place organisms in monophyletic groups. Contains all known descendants of a common ancestor (eg. mammals) Paraphyletic taxon, reptiles true monophyletic group would be birds and reptiles together, as birds are the result of dinosaurs. Proof being found recently show that most dinosaurs has feathers. Whales should be where birds are on tree. Does not share recent common ancestors shares homoplastic features (features which are derived from another individual of the same species) Misrepresents evolutionary relationships: protista is being re-examined, but is most likely not a real kingdom; multiple unrelated groups clumped together due to poor measures of shared characteristics (txt p 26) Example: historically, existent dolphins and extinct ichthyosaurs were grouped together.
