14. Eukaryotic diversity IIA

14. Eukaryotic diversity IIA - 1 Eukaryotic Diversity II 1...

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Unformatted text preview: 1 Eukaryotic Diversity II 1. We’ll return the exams today or Friday. 2. Clickers today 3. Friday – endosymbiosis HW due. 4. Friday - GAE involves a computer simulations of diffusion. 5. 3-student groups - bring one laptop with downloaded application called Mathematica Player, plus the diffusion simulation from the course website; 4-student groups – 2 laptops, if possible 6. Fully charged laptop, watch/timer, calculator, and gmail account C & R 28.1 1970’s hypothesis of eukaryote phylogeny Absorption Photosynthesis Ingestion Fungi Molds Algae Plants Protozoa Animals Ancestral eukaryote Protist diversity: 1) Poor coupling between protist phylogeny and nutritional strategy • Molds - absorptive, fungus-like protists • Algae - photosynthetic, plant-like protists • Protozoa - ingestive, animal-like protists Euglena C & R 28.3 Many lineages acquire, then lose plastids Colloquial terms - See F. Fig. 29.26 “Protist” Diversity Eight major lineages Nutrition – often results from convergence, only sometimes from phylogeny 2 Eukaryotic Diversity II C & R 28.1 • Eukaryotes evolved as complex assemblages of several organisms due to endosymbiosis. • Eukaryotes acquired aerobic respiration and oxygenic photosynthesis from bacterial endosymbionts. • Prokaryotes – lateral gene transfer Eukaryotes – endosymbiosis (with LGT) • Unifying features include: nucleus, linear chromosomes, endomembrane system, and complex cytoskeleton. • Eukaryotes manifest more organellar, cellular, and multicellular diversity than prokaryotes • Eukaryotes originated the sexual stages, i.e., syngamy and meiosis, in life cycles. • Protists - paraphyletic group including all eukaryotes except plants, fungi, and animals Plastid evolution - A tale of two metaphors (Darwin’s Tree of Life vs. Delwiche’s Babushka Dolls) ht p:/ arts.anu.edu.au F. Fig. 28.7 “It is the best of times, and it is the worst of times to be studying plastid evolution” - Chuck Delwiche (CBMG) Deep Mysteries of Plastid Evolution red plastids green plastids brown plastids All plastids have chlorophyll a , with different accessory pigments mitochondrial origin 1° plastid with cell wall 1° plastid without cell wall 1° plastid – red green Sally Gibbs Plastid evolution - 2º endosymbiosis 1º endosymbiosis - primary plastids with 2 membranes F Fig. 29.17 1º endosymbiosis - mitochondrion 2°/sometimes 3° endosymbiosis of plastid origins in many lineages red plastids green plastids brown plastids 3 Eukaryotic Diversity I C & R 28.1 • Eukaryotes evolved as complex assemblages of several organisms due to endosymbiosis....
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This note was uploaded on 02/01/2012 for the course BSCI 207 taught by Professor Higgins during the Spring '08 term at Maryland.

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14. Eukaryotic diversity IIA - 1 Eukaryotic Diversity II 1...

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