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Unformatted text preview: Lecture 5 Classification A. Classification- The discovery and expression of the relationship between facts- You look for the similarities and differences, and then you can place them into groups B. Taxonomy- The science that studies classification- Give it a name, describe it, classify it (put it into a group)- How do you place them into groups? It is ongoing and controversial still DNA analysis is driving this field When you figure out who is related to who, you can figure out how it happened C. Phylogenetic Classification Modern taxonomy shows the evolutionary history (phylogenetic = who evolved from who?)- Cladograms (fig. 23-8) Figure A is an evolutionary classification- Evolutionary classification takes into account: Common ancestry: makes something phylogenetic (family tree) Degree of difference: how much something has changed Paraphyletic = all members that evolved from a common ancestor are not included in that group (taxon) The problem with this approach is all members of a group may not be included because they look so different- Phylogenetic classification (cladistics) is based only on common ancestry (figure B) Monophyletic = the group reptiles has one common ancestor, which gave rise to all members of that group- Phenetic Counting every characteristic (used in molecular biology) Look at the sequence, how many are the same?...
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- Spring '08