Kingdom Monera What are PROKARYOTES They are ancient

Kingdom Monera What are PROKARYOTES? They are ancient life forms known as bacteria • No nucleus • No chloroplasts • No mitochondria Two major clades of bacteria Archaebacteria & Eubacteria Methanogens Extreme Thermophiles Extreme Halophiles Cyanobacteria (Blue-green algae) & other Gram negative bacteria Gram positive bacteria TEM of dividing cell

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 • Small ribosomes (70 S) for protein synthesis Other constituents? Gas vacuoles; Cell walls; Storage molecules for N, P, C

Geoclock Origin of life

Cyanophytes established early aerobic environments. Evolution of advanced aerobes 2 H 2 O + CO 2 + CH 2 O + H 2 O “Primordial ANAEROBIC soup”

More conventional geologic time table MYA 2 ERA PERIOD Quaternary 65 150 Cenozoic Tertiary Cretaceous 200 250 Mesozoic Jurassic Triassic DOMINANT LIFE FORM Age of angiosperms Rise of angiosperms Age of cycads Rise of cycadophytes Rise of conifers 300 350 Permian Carboniferous Age of lycopods, ferns, sphenopsids; Rise of mosses 400 450 Devonian Silurian Age of vascular plants; 1 st seed plants 1 st vascular plants 500 600 Ordovician Cambrian Age of eukaryotic algae Rise of eukaryotic algae and fungi 4500 Precambrian Rise of prokaryotes

Division Cyanophyta Bacteria that are: • Photosynthetic (convert light energy to food) • Produce O 2 as a byproduct of photosynthesis • Some produce toxins • Some have capacity to fix N 2 into NH 4 • Some have formed millions of years old stromatolites as living structures Cyanophytes have changed the path of evolution on earth TEM of dividing cell

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 Ancient organisms but well suited to earth’s habitats 2000 species, 150 genera Habitats: virtually everywhere Oceans Soil Epiphytes Freshwater Hotsprings Endophytes Morphological Range: Unicells to complex multicell organisms Cell Walls: Gram negative bacteria Trichodesmium blooms can cover 2 x 106 km 2 and be seen via satellites NASA

Diversity

Cell Walls Being comprised of only 20% peptidoglycan, the cell wall of Gramnegative 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

General features Pigments - photosynthesis • Chlorophyll a • Phycobilins Phycoerythrin Phycocyanin Allophycocyanin Others • Carotenoids • UV absorbing molecules Storage Products Growth

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 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

General features Pigments - photosynthesis • Chlorophyll a • Phycobilins Phycoerythrin Phycocyanin Allophycocyanin Others • Carotenoids • UV absorbing molecules Storage Products • Starch (C) • Cyanophycin (N) • Poly Pi bodies Growth

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 (70 S) Cell walls ? Storage molecules for N, P, C ? Floatation?

General features Pigments - photosynthesis • Chlorophyll a • Phycobilins Phycoerythrin Phycocyanin Allophycocyanin Others Storage Products • Every cell can • Starch (C) • Cyanophycin (N) • Multicellular organisms: • Poly Pi bodies Growth Fragments regrow “Spores” regrow Akinetes germinate • Branching • Carotenoids True branching • UV absorbing molecules False branching

Growth & morphology 1 1 Binary Fission (cell division) 1 1 1 Cell division for unicells: unicells 2 Produces genetically identical “offspring” or twins Increases the numbers of cells in the population by exponential growth, 2 n Divisions may be every 15 to 20 min 4 8 16 cells

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 / m. L in “blooms”

Developmental lineages Evaluate adult form to gain insight in possible processes. evolutionary 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 Genetic change Developmental Lineage #1 Order Chroococcales All cells appear virtually identical internally Evolution has taken a simple shape to more complex but related forms: forms • Multicellular genera

Diversity Order Chroococcales Microcystis Merismopedia

Growth & morphology 1 colony Coordinated binary fission of all cells in colony Multicellular organisms divide but increase the number of entities in the population 2 colonies

Growth & morphology Evolution has taken a simple shape: • attachment to the substrate • spores released from upper end of cell Developmental Lineage #2 Order Chamaesiphonales

Growth & morphology Developmental Lineage #3 trichome + sheath Order Nostocales (filament) trichome (no sheath evident) Evolution has taken a simple shape: • constrained cells into chains • formed arrays of trichome(s) in sheaths • false branching can result trichomes + sheath

Diversity Order Nostocales

Growth & morphology False branching Order Nostocales : 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 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 N 2 NH 4+ polar heterocysts

Growth & morphology Order Nostocales Nitrogen fixation & Azolla in rice fields replace fertilizers 1. Low N in environment 2. Heterocysts differentiate 3. Enzyme converts N 2 NH 4+ 4. Water fern benefits from fertilizer 5. Rice fields are more productive intercalary heterocysts

Other cell types Akinete Anabaena Order Nostocales

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 True branching Order Stigonematales : 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 Complex tissue • Multicellular • Organized multiseriate layers • Cell dimorphism Order Stigonematales

Vocabulary prokaryote binary fission thylakoid phycobilins phycobilisome akinete multiseriate trichome false branching nitrogenase eukaryote nucleus chloroplast mitochondrion accessory pigment heterocyst uniseriate sheath true branching photosynthesis Azolla Anabaena Lyngbya Stigonema

Who am I?

Reading & Viewing Scientific American Extremophiles: http: //www. spaceref. com/redirect. html? id=0&url=www. sciam. com/0497 issue/0497 marrs. html National Geographic: http: //www. nationalgeographic. com/world/0010/bacteria. html An underworld of hydrogen sulfide harbors life-forms awesome and awful: http: //www. nationalgeographic. com/ngm/0105/feature 4/index. html NASA interactive page http: //nai. arc. nasa. gov/_global/shockwave/g 3_matgallery. swf Powers of ten interactive page: http: //microscopy. fsu. edu/primer/java/scienceopticsu/powersof 10/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/stromatolites_in_the_hakatai/ http: //www. ngdc. noaa. gov/mgg/sepm/palaios/9810/knoll. html