Ch 26 - Phylogeny and the tree of life (1 slide per page)-2

5 campbell et al 9th ed 26 26 polytomy a node where 3

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Unformatted text preview: es emerge = unclear on the order that groups diverged (rapid divergence or evidence poor) Polytomy See Figure 26.5 (Campbell et al 9th ed) 27 27 Be careful how you interpret phylogenetic trees A 1 2 B 3 C See Figure 26.5 (Campbell et al 9th ed) • DO NOT assume that branch lengths represent the amount of: • time since genetic divergence from the most recent ancestor • genetic divergence from the most recent ancestor 28 28 But branch lengths COULD represent time but only if it is labeled as such 29 29 Be careful how you interpret phylogenetic trees DO NOT assume that a taxon evolved from the taxon next to it but only that they shared the most recent common ancestor e.g. Hominins (incl. humans) did NOT evolve from chimps! But, chimps and humans did share a similar common ancestor (and both have changed considerably since this node) 30 30 Trees of different configurations can have the same meaning 37 37 A Monophyletic Group (aka clade) includes an ancestral species and ALL of its descendants “Arthropoda” • MRCA of all “arthropods” was also an “arthropod”. Use the “snip test” to determine if it is a monophyletic group MRCA See Figure 26.10 (Campbell et al 9th ed) 38 38 A Paraphyletic G...
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This note was uploaded on 02/12/2014 for the course BIOLOGY 2011 taught by Professor Woo during the Fall '10 term at University of Central Florida.

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