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Kingdom Monera. What are PROKARYOTES ?. They are ancient life forms. known as bacteria. No nucleus. No chloroplasts. No mitochondria. Two major clades of bacteria. TEM of dividing cell. Archaebacteria. & Eubacteria. Cyanobacteria (Blue-green algae) & other. Methanogens
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Kingdom Monera What are PROKARYOTES? They are ancient life forms known as bacteria • No nucleus • No chloroplasts • No mitochondria Two major clades of bacteria TEM of dividing cell Archaebacteria & Eubacteria Cyanobacteria (Blue-green algae) & other Methanogens Extreme Thermophiles Extreme Halophiles Gram negative bacteria Gram positive bacteria
Prokaryotes Lack Organelles(w/ 2 membranes) • No nucleus but have DNA & RNA • No chloroplasts but have pigments, thylakoids & enzymes for PS • No mitochondria but have respiratory chain & membranes Other constituents? Gas vacuoles; • Small ribosomes (70S) for protein synthesis Cell walls; Storage molecules for N, P, C
Geoclock Origin of life
Cyanophytes establishedearly aerobic environments. Evolution of advanced aerobes 2 H2O + CO2 O2 + CH2O + H2O “Primordial ANAEROBIC soup”
Division Cyanophyta Bacteriathat are: • Photosynthetic (convert • light energy to food) • Produce O2 as a byproduct of photosynthesis • Some produce toxins TEM of dividing cell • Some have capacity to fix N2 into NH4 • Some have formed millions of years old • stromatolitesas living structures Cyanophytes have changed the path of evolution on earth
Things we will cover General features - defining characteristics Developmental lineages – using morphology to understand evolution Ecology – understanding roles in interacting with other species Commercial interests – exploit ecology Evolution – diversity and change over time
General features Habitats: virtually everywhere Ancient organisms but well suited to earth’s habitats Oceans Freshwater 2000 species, 150 genera Soil Hotsprings Epiphytes Endophytes Morphological Range: Unicells to complex multicell organisms Cell Walls: Gram negative bacteria Trichodesmium blooms can cover 2x106 km2 and be seen via satellites NASA
Cell Walls Being comprised of only 20% peptidoglycan, the cell wall of Gram-negative bacteria is much thinner than Gram-positive bacteria. • Gram-negative bacteria have two unique regions which surround the outer plasma membrane: i) periplasmic space and ii) lipopolysaccharide layer. • periplasmic space separates the outer plasma membrane from the peptido-glycan layer. • lipopolysaccharide layer is adjacent to the exterior peptidoglycan layer
Pigments - photosynthesis General features Storage Products Growth • Chlorophyll a • Phycobilins Phycoerythrin Phycocyanin Allophycocyanin Others • Carotenoids • UV absorbing molecules
Photosynthesis & Pigments sunlight • Light energy is harvested • by the cell • Only specific colors are absorbed Cell • Other colors are reflected back to your eye thylakoids Chl a Chl a Phycobilins
Chlorophyll a Tetrapyrrole Ring Phytol Chain
Phycobilins Open tetrapyrrole phycoerythrin phycocyanin
Photosynthesis & Pigments • Arrangement of light • harvesting structure is • specific and detailed Chlorophyll a
Pigments - photosynthesis General features Storage Products Growth • Chlorophyll a • Starch (C) • Phycobilins • Cyanophycin (N) Phycoerythrin • Poly Pi bodies Phycocyanin Allophycocyanin Others • Carotenoids • UV absorbing molecules
Storage products Starch C = black O = red H = white C = green = blue H = red = white P = purple ATP
General features What is in a typical cyanophyte cell? DNA & RNA Pigments, thylakoids & enzymes for PS Respiratory chain & membranes Small ribosomes (70S) Cell walls ? Storage molecules for N, P, C ? Floatation?
Pigments - photosynthesis General features Storage Products Growth • Every cell can • Multicellular organisms: • Chlorophyll a • Starch (C) • Phycobilins • Cyanophycin (N) Fragments regrow Phycoerythrin • Poly Pi bodies “Spores”regrow Phycocyanin Akinetes germinate Allophycocyanin • Branching Others True branching • Carotenoids False branching • UV absorbing molecules
Growth & morphology 1 1 Binary Fission (cell division) 8 16 cells 1 1 1 4 2 Cell division for unicells: Produces genetically identical “offspring” or twins Increases the numbers of cells in the population by exponential growth, 2n Divisions may be every 15 to 20 min
Growth & morphology Unicell populations grow rapidly Cyanotech ponds Starting with 1 cell: 10 rounds of division 1,000+ cells It’s not unusual to have 10 6 to 108 cells / mL in “blooms”
Developmental lineages Evaluate adult form to gain insight in possible evolutionary processes. Step-by-step acquisition of new traits via genetic change. Examine reproductive cells and other characters as additional data. Useful means to construct evolutionary hypotheses to test with molecular data.
Growth & morphology Developmental Lineage #1 Order Chroococcales Genetic change All cells appear virtually identical - internally Evolution has taken a simple shape to more complex but related forms: • Multicellular genera
Diversity Order Chroococcales Microcystis Merismopedia
Growth & morphology 1 colony Coordinated binary fission of all cells in colony 2 colonies Multicellular organisms divide but increase the number of entities in the population
Growth & morphology Developmental Lineage #2 Order Chamaesiphonales Evolution has taken a simple shape: • attachment to the substrate • spores released from upper end of cell
Growth & morphology Developmental Lineage #3 Order Nostocales trichome + sheath (filament) trichome (no sheath evident) Evolution has taken a simple shape: • constrained cells into chains • formed arrays of trichome(s) in sheaths trichomes + sheath • false branching can result
Diversity Order Nostocales
Growth & morphology Order Nostocales False branching : 1. Rupture of sheath and cells 2. Remaining cells at both ends continue to grow 3. Both trichomes push through weakened sheath What to look for? Is there a change in the plane of cell division?
New Cell Types Order Nostocales polar heterocysts Nitrogen fixation supports protein synthesis 1. Low N in environment 2. Cell differentiates as a specialized cell, the heterocyst 3. Creates setting for Nitrogenase enzyme 4. Enzyme converts N2 NH4+
Growth & morphology Order Nostocales Nitrogen fixation & Azolla in rice fields replace fertilizers 1. Low N in environment 2. Heterocysts differentiate 3. Enzyme converts N2 NH4+ 4. Water fern benefits from fertilizer 5. Rice fields are more productive intercalary heterocysts
Other cell types Order Nostocales Akinete Anabaena
Cool stuff Order Nostocales
Growth & morphology Developmental Lineage #4 Order Stigonematales True branching Evolution has taken a simple shape: • formed arrays of cells that divide in 2 directions (planes) Multiseriate tissues
Growth & morphology Order Stigonematales True branching : 1. No rupture of sheath or cells 2. Cells divide in two planes 3. Create new structures, branches What to look for? Is there a change in the plane of cell division?
Growth & morphology Order Stigonematales Complex tissue • Multicellular • Organized multiseriate layers • Cell dimorphism
Vocabulary prokaryote eukaryote binary fission nucleus thylakoid chloroplast phycobilins mitochondrion phycobilisome accessory pigment akinete heterocyst multiseriate uniseriate trichome sheath false branching true branching nitrogenase photosynthesis Azolla Lyngbya Anabaena Stigonema
Reading & Viewing Scientific American Extremophiles: http://www.spaceref.com/redirect.html?id=0&url=www.sciam.com/0497issue/0497marrs.html National Geographic: http://www.nationalgeographic.com/world/0010/bacteria/bacteria.html An underworld of hydrogen sulfide harbors life-forms awesome and awful: http://www.nationalgeographic.com/ngm/0105/feature4/index.html NASA interactive page http://nai.arc.nasa.gov/_global/shockwave/g3_matgallery.swf Powers of ten interactive page: http://microscopy.fsu.edu/primer/java/scienceopticsu/powersof10/index.html Mereschowsky, C., (1905). Über Natur und Ursprung der Chromatophoren im Pflanzenreiche., Biol. Centr. 25, 593-604 & 689-691. Mereschowsky, C., (1910). Theorie der zwei Plasmaarten als Grundlage der Symbiogenesis, einer neuen Lehre von der Entstehung der Organismen., Biol. Centr. 30, 353-367, 1910. Margulis, L. (1970). Origin of eukaryotic cells. Yale University Press, New Haven.
Picture credits http://www.nhm.uio.no/palmus/galleri/montre/english/gruppe_liste_e.htm http://astrobiology.arc.nasa.gov/roadmap/goals/index.html http://www.lalanet.gr.jp/nsm/E-stromatolite.html http://www.petrifiedseagardens.org/main.htm Saratoga Springs NY http://www.rockhounds.com/grand_hikes/hikes/stromatolites_in_the_hakatai/ http://www.ngdc.noaa.gov/mgg/sepm/palaios/9810/knoll.html