1. Cladistics and Molecular Systematics

10. Depicting evolutionary changes

12. Homology

13. Homoplasy

18. Grouping rules
Only synapomorphies are evidence for common ancestry relationships.
Convergences and parallelisms evolved independently so they cannot provide information about common ancestry.
Symplesiomorphies cannot show common ancestry within the group because they evolved earlier in the hierarchy.

21. Parsimony Most common method of choosing among trees
Minimizes evolutionary change
Occam’s Razor - Do not generate a hypothesis any more complex than the data demands

22. Combining trees

23. Characters for Cladistics
Qualitative – presence / absence
Multistate
Meristic – counting parts
Quantitative – measurements

24. Morphological characters
Limited numbers of characters
Many characters vary continuously
Homologies may be hard to discern

25. Molecular Systematics

26. Plant Genomes Chloroplast 135-160 kbp (cpDNA)
Mitochondrion ,500 kbp (mtDNA)
Nucleus x x 109

28. ITS - Internal Transcribed Spacer region of ribosomal DNA

31. Molecular characters
Point mutations
Insertions
Deletions
Inversions

34. Molecular characters Enormous numbers of characters
Four states for each character
Different parts of the genome accumulate mutations at different rates – possible to examine relationships at different levels

35. Classifications Artificial – group taxa according to similarities
Natural – group taxa according to evolutionary relationships
Traditional – intuitive
Phenetic – based on similarities
Cladistic – based on evolutionary links

36. Angiosperm Phylogeny Group
Angiosperms

37. Angiosperm Phylogeny Group
Eudicots