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

Legs legs legs legs legs mrca wo legs 68 68 principle

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Unformatted text preview: Legs + Legs MRCA w/o legs 68 68 Principle of parsimony allows us to arrive at the most likely scenario • Only some of these groups have legs • What different ways could this pattern could have arisen? + Legs – Legs + Legs – Legs + Legs MRCA w/o legs 69 69 Parsimony Most likely hypothesis is the one that needs the least amount of change to explain actual results. Aka Occam’s Razor: Start with the simplest explanation that’s consistent with the data + Legs 70 70 Parsimony Can be applied to almost any kind of data Chromosome structure (each color is a diff. gene) What is the simplest explanation that may have led to this pattern? 71 71 Parsimony Due to analogies parsimony doesn’t always work • Analogies: streamlined body, long jaws, flippers • Do not reflect true evolutionary history 72 72 Parsimony For best results, base relationships on many different characters. Based on many other characters: Dolphins = mammals Ichthyosaur = reptile 74 74 Parsimony For best results, use many different characters. 79 79 New information continues to revise our understanding of the tree of life Figure 26.21 Campbell et al (9th ed) Figure 26.23 Campbell et al (9th ed) 80 80 Readings on which you will NOT be tested • Figure 26.6 (Inquiry) • Figure 26....
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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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