BOT201 2004 DIATOM DINOFLAGELLATE LECTURE

BOT201 2004 DIATOM DINOFLAGELLATE LECTURE - Kingdom...

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Unformatted text preview: Kingdom Protista Diatoms Green algae Simple Eukaryotes Red algae J e Kingdom Protista Division Bacillariophyta, plankton land plants evolve Recent plants, ~150 mya "Standard" eukaryote cells No multinucleate cells Motile cells present Non-standard chloroplasts Non-standard cell walls General features 10,000 species (90 in HI oceans) 285+ genera (40 in HI) Morphological Range: Single cells to chains of cells Recently arrived eukaryotes well suited to coasts and open ocean General features Pigments photosynthesis Storage Products Growth Chlorophyll a Chlorophyll c Fucoxanthin Others Carotenoids UV absorbing molecules Photosynthesis & Pigments Light energy is harvested by the cell sunlight Only specific colors are absorbed Other colors are reflected back to your eye thylakoids Chl a, c Chl a, c fucoxanthin General features How are phaeophyte cells unusual? "New" membranes around chloroplast & nucleus First step: Second step: Repeated endosymbioses Second eukaryote General features Pigments photosynthesis Storage Products oils (C) Growth Cell wall - unique Bilaterally symmetric Pennate Chlorophyll a Chlorophyll c Fucoxanthin Radially symmetric Centric Cell wall structure Glass house with overlapping parts is a frustule: epi valve - upper larger portion TOP hypo valve lower, smaller portion BOTTOM "girdle" region region of overlap SIDE Cell wall structure Frustule has many pores Create elaborate patterns Allow for communication with exterior What views are these ? Valve view? Girdle view? General features What consequences arise from this cell wall ? Rigid cell wall limits cell size Each round of cell division creates smaller cells on average Cell reach critical limits General features What consequences arise from this cell wall ? Rigid cell wall limits cell size Each round of cell division creates smaller cells on average Cell reach critical limits Life History as a "Strategy" Zygotic Meiosis Life History Gamete DOES NOT OCCUR IN DIATOMS Gamete Meiosis Zygote Meiosis is associated with Zygote Germination Life History as a "Strategy" DOES NOT OCCUR IN DIATOMS Meiosis is associated with Spore Production Diversity Centric diatoms Coscinodiscus Life History as a "Strategy" Meiosis is associated with Gamete Production Life history as a "Strategy" Growth & morphology Pennate diatoms Pennate diatoms Navicula Central slit in frustule, a raphe Life History as a "Strategy" Meiosis is associated with Gamete Production Life history as a "Strategy" mitosis mitosis Chaetoceros zygote Diversity Pennate diatoms Tabellaria cells Navicula in polysaccharide tube Eunotia Licmorphora Life History as a "Strategy" Meiosis is associated with Gamete Production Kingdom Protista Division Pyrrhophyta, dinoflagellates Recent origin, ~400 mya land plants evolve Non standard eukaryote cells Meso karyote nuclei Motile but 2 flagella No cell walls Non-standard chloroplasts General features 4,000 species (45 in HI oceans) 550 genera (~25 in HI) Morphological Range: Single cells to chains of cells Recently evolved but primitive meso karyotes well suited to coasts and open ocean General features Pigments Chlorophyll a Chlorophyll c Peridinin photosynthesis Storage Products Starch (C) Growth Every cell can divide Cell wall - none Cells built in parts 2 flagella Girdle or cingulum "Keel" or sulcus Inner framework of cellulose Epi theca Hypo theca Growth & morphology Noctiluca scillantans Ceratium sp Ceratocorys sp Life History as a "Strategy" Zygotic Meiosis Life History Gamete Zygote Gamete Meiosis Meiosis is associated with Zygote Germination Symbiodinium as intracellular coral symbiont Photosynthate supports coral growth Bleaching results from loss of zooxanthellae Probably THE most common alga on tropical reefs. Life History as a "Strategy" Gymnodinium Zygotic Meiosis Life History as a "Strategy" Pfeisteria piscida Zygotic Meiosis Life History as a "Strategy" Noctiluca Gametic Meiosis ! Ecology Ciguatera poisoning (tropical) Saxitoxin poisoning (temperate) A type of red tide or harmful algal bloom of particular species. High concentrations, blooms, of dinoflagellates introduce toxin in food web. Toxin effects are to disrupt neurotrasmittors; leads to paralysis with no known cure. saxitoxin ...
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