BIOL 1020H Chapter Notes - Chapter 23: Radiometric Dating, Extinction Event, Comparative Anatomy
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Speciation can be thought of as process of branching: a node represents the most recent common ancestor of two descendant species. Taxonomy is the classification of organisms: the goal is to recognize and name groups of individuals as species, genus, family, order, class, phylum, kingdom, and domain. 23. 2 building a phylogenetic tree (pg 468-474: homology is similarity by common descent. Shared derived characters enable biologists to reconstruct evolutionary history. Synapomorphies: a shared derived character; a homology shared by some, but not all, members of a group. Cladistics: phylogenetic reconstruction on the basis of share evolutionary changes in characters, often called synapomorphies. Each change corresponds to a mutation in an ancestral species. The simplest tree is often favored among multiple possible trees. Parsimony: choosing the simpler of two or more hypotheses to account for a given set of observations: molecular data complement comparative morphology in reconstructing phylogenetic history.
