BSC 116 Lecture Notes - Lecture 3: Foodborne Illness, Facultative Anaerobic Organism, Escherichia Coli
24 Jan 2017
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Molecular characters allow us to assess relationships when there is little morphology to go on: molecular phylogenetics, molecular clocks. Traditional view of organismal diversity: 5 kingdoms: kingdom monera. Multi-celled eukaryotes: this classification is a hypothesis about evolutionary relationships and character change. Single-celled vs. multi-celled: this view of the tree of life has not held up in analyses of molecular data. Protista was a "garbage can taxon" of organisms that didn"t fit into other categories. Current view: 3 domains: 3 distinct clades (monophyletic) Paraphyletic (ancestor and some descendants: multi-cellular life not monophyletic. Two clades of prokaryotes: bacteria and archaea, knew most about bacteria. Modern prokaryotes give info about original forms of life: characteristics tell us about the evolutionary transition to eukaryotes. Prokaryotes were the only life on earth 3. 6-2. Total mass = 10 * total eukaryotic mass: difficult to know how many species there are. Only really know the ones we can grow in the lab: three basic shapes.
