PLB 300 Lecture Notes - Lecture 16: Cyanobacteria, Heliobacteria, Bacteriochlorophyll
Document Summary
Clade (monophyletic) an ancestor and all its descendants. Paraphyletic group an ancestor and only some descendants: can be rotated without changing meaning of the tree, represent speciation events where ancestral taxon splits. Changing the branching pattern changes meaning of the tree. Polytomies: soft polytomies: uncertainty, hard polytomies: hypothesis of 3 (or more) simultaneously splitting descendant taxa. Phenetics: traditional classification used comparison of overall similarity, simpler than cladistics, sometimes can lead to wrong conclusions, these look similar but . Milkweed family: more objective, more likely to recover accurate evolutionary relationships, groups organisms using shared, derived characters, produces a phylogenetic tree that requires the fewest evolutionary changes, trees represent estimates of evolutionary relationships. Use of cladistic analyses and or molecular modeling to estimate phylogeny. Work of carl woese discovered new kind of prokaryotic organism in 1970s. Lack nucleus, nuclear envelope: dna localized in nucleoid. Most lack membrane-bound organelles: may have microcompartments to house enzymes.
