BIOA01H3 Chapter Notes - Chapter 23: Monophyly, Paraphyly, Polyphyly

• School: UTSC
• Department: Biological Sciences
• Course: BIOA01H3
• Professor: Mark Fitzpatrick

Document Summary

Node: a representation of a common ancestor between two descendant species: the connection point of two branches is a node. Phylogenetic: the study of evolutionary relationships among organisms: phylogenetic tree: the visual hypothesis about the evolutionary history of species, construction is based on morphological and molecular similarities, sister taxa: groups/ taxa which are the most closely related. Indicated by a closely shared node: monophyletic group: all members of the group share the same common ancestor. Indicates that all tetrapods are monophyletic: paraphyletic: includes some, not all, of the descendants of the common ancestor, fig 3. Indicates, within sauropsids, reptiles are paraphyletic as it excludes birds. While grouping, if you make one cut then it"s a monophyletic group. However, if you make two cuts then it is a paraphyletic group: polyphyletic: includes select common descendants of a common ancestor, fig 3. Indicates, bats and birds form a polyphyletic group.