Phylogeny and the Tree of Life

1. Phylogeny and the Tree of Life AP Biology Crosby High School

2. Taxonomy • Binomial Nomenclature • Genus specium • Hierarchical Classification • Domain • Kingdom • Phylum • Class • Order • Family • Genus • Species • PhyloCode?

3. Terminology • Dichotomies • Sister Taxa • Rooted • Basal Taxon • Polytomy

4. Cladistic Analysis • Clade • Cladogram: Phylogenetic diagram • Dichotomies • Monophyletic (“single tribe”)

5. Constructing a Cladogram • Created from Homology not Analogy • More similar Homologies are more closely related • The more complex two structures are the more likely they are homologous • Shared Primitive Character: common to more inclusive taxon • Mammal backbone • Shared Derived Character: unique to defined taxon • Mammal hair

6. Outgroup Comparison • Outgroup: Very distant from studied Organisms • Ingroup: Studied Organisms • Which one of these things is not like the other? • Ancestor more recent, not species

7. Molecular Cladograms • Constructed from differences in DNA sequences • rRNA used for taxa that diverged from 100s to millions of years ago • mtDNA used for more recent divergences • Insertions and Deletions must be accounted for

8. Parsimony • Keep it simple • Requires the least amount of changes or evolutions to occur

9. Phylogenetic Trees are Hypotheses • They are a guess • Most parsimonious = most accepted • Unless evidence proves otherwise • The same evolutionary event occuring more than once in unrelated cases is unlikely • Strongest hypotheses are supported by morph., molec., and fossil record

10. Parsimony

11. DNA Allignment

12. Outgroup Comparison