L7 first by - BILD 3 July 7 2010 EXPLORING BIODIVERSITY SIX...

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BILD 3 July 7, 2010 Woodruff: life's first 4 billion years 1 EXPLORING BIODIVERSITY SIX LECTURES BACTERIA ARCHAEA 2 billion years of only prokaryotes 4 billion years of successful life at the left wall of minimal complexity EUKARYA ENDOSYMBIOSIS FORMER PROTISTS CAMBRIAN EXPLOSION EXPLORING BIODIVERSITY SIX LECTURES BACTERIA ARCHAEA 2 billion years of only prokaryotes 4 billion years of successful life at the left wall of minimal complexity EUKARYA ENDOSYMBIOSIS FORMER PROTISTS CAMBRIAN EXPLOSION Nuclear membrane Membrane-enclosed organelles Peptidoglycan in cell wall THREE DOMAINS Campbell p. 552 3.0 – 3.5 BILLION YEAR OLD BACTERIA, CYANOBACTERIA ORIGIN OF ORGANELLES BY ENDOSYMBIOSIS SOME PROKARYOTES & ALL EUKARYOTES ARE COMPOSITE ORGANISMS INVASIONS MITOCHONDRIAL 2.0 BYA “spirochaete” FLAGELLUM 1.5 BYA PLASTIDS 1.4 BYA p. 517, 553 HORIZONTAL GENE TRANSFER EVOLUTION AS PROGRESS? PROKARYOTE EVOLUTION STASIS EVOLUTION AS PROGRESS? PROKARYOTE EVOLUTION BY HORIZONTAL GENE TRANSFER PROKARYOTE SHAPES
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BILD 3 July 7, 2010 Woodruff: life's first 4 billion years 2 BACTERIAL FLAGELLUM MOTOR NATURE EVOLVES THE WHEEL BACTERIAL CELL-WALL COMPOSITION: PEPTIDOGLYCAN with 1 or 2 plasma membranes Gram stain positive or negative Fig. 27-7 (a) Aerobic prokaryote (b) Photosynthetic prokaryote Thylakoid membranes Respiratory membrane 0.2 µ m 1 µ m Infolding of external plasma membrane to produce internal membranes for respiration or photosynthesis Concept 27.3: Extraordinarily diverse nutritional and metabolic adaptations have evolved in prokaryotes Phototrophs obtain energy from light Chemotrophs obtain energy from chemicals Autotrophs require CO 2 as a carbon source Heterotrophs require an organic nutrient to make organic compounds These factors can be combined to give the four major modes of nutrition: photoautotrophy, chemoautotrophy (including lithoautotrophy), photoheterotrophy, and chemoheterotrophy REPRODUCTION BY SIMPLE FISSION Prokaryotes reproduce quickly by binary fission and can divide every 1–3 hour Species are hard to define in bacteria because of rampant horizontal gene transfer. Microbial populations are blended and lineages anastamose repeatedly. Sex pilus Many prokaryotes form metabolically inactive endospores , which can remain viable in harsh conditions for centuries Anthrax, Clostridium
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BILD 3 July 7, 2010 Woodruff: life's first 4 billion years 3 DOMAIN BACTERIA PROTEOBACTERIA: 5 diverse groups (alpha – epsilon) CHLAMYDIAS SPIROCHETES CYANOBACTERIA GRAM-POSITIVE BACTERIA Fig. 27-18a Alpha Beta Gamma Delta Epsilon Proteobacteria Subgroup: Beta Proteobacteria Nitrosomonas (colorized TEM) 1 µ m Subgroup: Delta Proteobacteria 10 µ m Fruiting bodies of Chondromyces crocatus , a myxobacterium (SEM) Bdellovibrio bacteriophorus attacking a larger bacterium (colorized TEM) 5 µ m Helicobacter pylori (colorized TEM) Causes stomach ulcers 2 µ m 0.5 µ m Subgroup: Epsilon Proteobacteria B. bacteriophorus Thiomargarita namibiensis containing sulfur wastes (LM) Subgroup: Gamma Proteobacteria
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