BOT201 2004 RHODOPHYTA Lecture

BOT201 2004 RHODOPHYTA Lecture - Kingdom Protista Brown...

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Unformatted text preview: Kingdom Protista Brown algae Green algae Simple Eukaryotes Red algae J e Kingdom Protista Kingdom Division Rhodophyta • Ancient plants, 1.6 bya • Unusual eukaryotes No motility Only 1 gamete type Only 1 life history land plants evolve Earliest red algae Precambrian General features General Most diverse group in ocean 5,500 species (345 in HI) 500+ genera (142 in HI) Morphological Range: Unicells to complex multicell organisms Ancient eukaryotes well suited to coastal habitats Photosynthesis Photosynthesis & Pigments • Light energy is harvested by the cell sunlight • Only specific colors are absorbed • Other colors are reflected back to your eye Cell thylakoids Chl a Phycobilins Chl a Photosynthesis Photosynthesis & Pigments • Arrangement of light harvesting structure impacts thylakoid stacking Chlorophyll a Evolution of eukaryotes Xenogenous hypothesis Xenogenous heterotrophs Simple cells phagocytosis Easy scenario for red algae autotrophs Mereschowsky, 1905; 1910 Cell wall structure Two essential parts: • fibers of cellulose (rigid), a glucose polymer • gels of sugar polymers, or polysaccharides (flexible) Cell wall structure Gel polysaccharides Agarophyte Gracilaria Carrageenan producer Kappaphycus General features Pigments Pigments photosynthesis Storage Products Products • Floridean Starch (C) (C) • Every cell can divide Growth • Chlorophyll a • Phycobilins • Many cells linked • Meristematic regions • Life histories Others • Carotenoids • UV absorbing molecules 2. Elaborate examples of Sporic meiosis General features General What is in a typical rhodophyte cell? • 90 % of cells do not completely divide • Open region eventually plugged with proteins “Pit plugs” General features General What is in a typical rhodophyte cell? “Pit plugs” • 90 % of cells do not completely divide • Open region eventually plugged with proteins • Primary pit plugs • Secondary connections can form General features What is in a typical rhodophyte cell? “Pit plugs” • Cytoplasmic connections can be re-established and eventually plugged with proteins • Secondary connections can form General features General What is in a typical rhodophyte cell? “Pit plugs” • Secondary connections add strength to filaments General features What is in a typical rhodophyte cell? “Pit plugs” • Secondary connections can form among different species! General features What is in a typical rhodophyte cell? • DNA & RNA • Chloroplast is large • Mitochondrion Porphyridium sp • Starch in cytoplasm Growth & Growth morphology ⇒ Mitosis (cell division) 21 ⇒ ⇒ ⇒ ⇒ ⇒ ⇒ 22 ⇒ ⇒ 24 C16) ⇒ 23 (8) Cell division by mitosis: mitosis (4) Produces genetically identical “offspring” Divisions are rapid Increases the numbers of cells exponentially Growth & Growth morphology Genetic change Developmental Lineage #1 Order Bangiales Cells appear identical internally Evolution has taken a simple shape to more complex but related forms: forms • Multicellular genera Porphyra Porphyra yezoensis Diversity Order Bangiales Porphyra linearis Bangia sp Life History as a Life Strategy Life History as a Life carpospores Strategy oogametes mitosis zygote germling meiosis Porphyra spores mitosis mitosis adult Porphyra yezoensis Diversity Order Bangiales Nori industry is now a global market Drew Baker figured out life history Breakthrough needed for successful culture & new industry Not much diversity in spore shape • No red algal spores can swim • Spores have NO flagella • Yet settlement is an important process Is it just random?? Porphyra yezoensis Diversity Order Bangiales Porphyra linearis Growth & Growth morphology Porphyra life history is unusual because: Different shapes to free living phases Gametophyte is macroscopic form Sporophyte is microscopic form Sporophyte has pit connections missing in gametophyte Sexual reproduction is common Almost all other Bangiales are asexual Transition from primitive order to “higher orders.” Diversity Diversity Primitive orders often have heteromorphic alternation of generations Asparagopsis taxiformis Life History as a Life Strategy Liagora sp Zygote develops within female gametophyte, a new phase meiosis Diversity Diversity Primitive orders often have heteromorphic alternation of generations Asparagopsis taxiformis Life history as a Life “strategy” Limu Kohu, Asparagopsis sp Zygote develops within female gametophyte, a new phase meiosis Grateloupia sp Diversity Diversity Intermediate Orders Kallymenia sp Rhodymenia sp Dudresnaya sp Diversity in Diversity Corallines Amphiroa sp Calliarthron sp Order Diversity uniaxial plants uniaxial Advanced Orders Chondria sp Pointed branches Hypnea sp Diversity Diversity Uniaxial plants Ceramium rubrum Martensia sp Leveillea sp. Life History as a Life Strategy Common Turf Polysiphonia sp Zygote develops within female gametophyte, a new phase meiosis Life History as a Life Strategy Liagora spp. Trichogloea spp. Galaxaura marginata Asparagopsis taxiformis Halymenia spp. Gracilaria salicornia Hypnea musciformis Gibsmithia hawaiiensis Pradaea weldii Acanthophora spicifera Gracilaria salicornia Gracilaria coronopifolia Dasya iridescens Portieria hornemanii Amansia glomerata Martensia fragilis Neomartensia flabelliformis Dasya iridescens Turf Algae Crustose Coralline Algae ANS in Hawaii: who, when, where and how? ANS Species Year Origin Guam Florida ?, Native to NW & SW Pacific, Indian Ocean, Australasia Vector Hull Fouling -Accidental Aquaculture -Intentional Aquaculture -Intentional Acanthophora 1950 spicifera Hypnea musciformis Gracilaria salicornia 1974 1971 Kappaphycus sp. Avrainvillea amadelpha 1974 1981 Philippines Native to NW & SW Pacific Aquaculture -Intentional Unknown ...
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