Diversity

• Protist


  Any eukaryotic organisms that is not animal, plant, fungus
• Protist


  • Have chlorophyll and accessory pigments for photosynthesis
  • Variations in cell structure—unicellular, colonial and multicellular forms

  
• Algal forms


  • Unicells (solitary)
  • Multicellular (filaments, chain)
  • Aggregations (strictly colonial)
• Reproduction


  • Vegetative (Hormogonia)
  • Asexual (spores)
  • Sexual & Binary fission
  • Sexual & Asexual
• Resting Cysts


  Unfavorable condition<|>Withstand extreme condition<|>Settle at the seafloor; afloat<|>Can last for long time
• Resting Cysts of diatoms

  Siliceous resting cyst = statosphora, stomacyst, statocyst
• Prokaryotic Algae


  No nuclear region and complex organelles—chloroplasts, mitochondria, Golgi bodies, and endoplasmic reticula<|>Chlorophylls are on internal membranes of flattened vesicles called thylakoids-contain photosynthetic pigments

  
• Eukaryotes


  Distinct chloroplast, nuclear region and complex organelles<|>Thylakoids are grouped into grana<|>Pyrenoids are centers of carbon dioxide fixation within the chloroplasts of algae
• Five (5) Main Taxonomic Groups

  • Bacillariophyta
  • Xanthophyceae
  • Chrysophyceae
  • Dinoflagellates
  • Cyanobacteria
  • Euglenoids
  • Chlamydomonas
• Bacillariophyta (Diatoms)


  • Siliceious cell walls = frustules
  • Nonmotile / sliding movements
  • Chlorophyll : a & c
  • Pigments : beta-carotene, phycoxanthin, xanthophyll
  • Storage: Leucosin, lipid, volutin
  • Pennate, centric

  
• Diatom Frustules


  Epitheca: Larger = older valve of the frustule with the girdle elements (epicingulum) connected with it<|>Hypotheca: Smaller = younger valve of the frustule with the girdle elements (hypocingulum) connected with it<|>Connective Zone: This zone is composed of the overlapping girdle elements of the diatom (the epicingulum and hypocingulum)<|>Septa: Partitions that are formed within the valves<|>Raphe: occurs in pennate diatoms as an elongated fissure in a valve, used by diatom for movement
• Diatom Cell Division


  1. Centric

  2. Pennate
• Xanthophyceae (Yellow-green algae)


  • Live primarily in freshwater, though some are found in marine waters, in damp soil, or on tree trunks
  • Pigments: xanthophylls and beta carotene
  • Single-celled flagellates to simple colonial and filamentous forms
  • Cell wall is unknown but inside some there are two silica valves similar to those in diatoms
• Chrysophyceae (Golden-brown algae)


  • Found mostly in freshwater
  • Often unicellular and have a flagellum, allowing them to be mobile in the water
  • Presence of a siliceous cyst : statospore, stomatocyst, statocyst
  • This structure usually contains a single pore
  • The surface of mature cysts are useful to distinguish species

  
• ~50 harmful species of Dinoflagellates
• ~100 harmful species of Diatoms
• ~10 harmful species of Cyanobacteria
• Dinophyta/Pyrrophyta


  Dinos "whirling' flagellum "whip"
• Dinophyta/Pyrrophyta


  • Unicellular and have two flagella (thread-like structures) of unequal length
  • The cells are surrounded by a complex theca and in some cases a thin additional layer, the pellicle
  • Photosynthetic, heterotrophic, mixotrophic, parasitic, kleptoplasty, symbiotic

  
• Dinokont


  TWO (2) dissimilar flagella arising from the ventral cell side<|>Ribbon-like transverse flagellum with multiple waves that beats to the cell's left<|>The longitudinal flagellum, that beats posteriorly<|>The transverse flagellum is a wavy ribbon<|>The flagellar movement produces forward propulsion and also a turning force
• Major Orders of Dinophyta/Pyrrophyta

  • Gymnodiniales
  • Peridiniales
  • Dinophysiales
  • Prorocentrales
  • Gonyaulacales
• Peridiniales


  • Biflagellated and free-swimming
  • A few are non-motile unicells reproducing by motile specialized cells (zoospores and gametes)
• Gymnodiniales


  • Members are known as gymnodinioid Athecate (lacking on armored exterior)
  • Mostly marine
• Gymnodiniales


  • Karenia brevis
  • Gyrodinium spiralae
  • Karlodinium veneficum
• Prorocentrales, Dinophysiales, Dinamoebales

  
• Asexual reproduction in Chlorophyta

  1. Growth Phase

  2. Ripening phase

  3. Post ripening phase

  4. Division Phase
• Chlorophyta (green algae) are photosynthetic, have chlorophyll a and b, xanthophylls, carotenes, and produce starch as food reserves
• Chlorophyta have both unicellular and multicellular forms, and their cell walls are made of polysaccharides, sometimes cellulose
• Chlorophyta reproduce both asexually and sexually
• Cyanophyta (cyanobacteria) are gram-negative bacteria that obtain energy via photosynthesis
• Cyanobacteria are thought to have originated in freshwater or a terrestrial environment, and later evolved into the chloroplasts of eukaryotic photosynthetic organisms through endosymbiosis
• Cyanobacteria produce a range of toxins known as cyanotoxins that can pose a danger to humans and animals
• Cyanobacteria


  • Some filamentous species can differentiate into vegetative cells, akinetes (climate-resistant spores), and heterocysts (which contain the enzyme nitrogenase for nitrogen fixation)
• Cyanobacteria have potential applications in biotechnology for bioethanol production, food colorings, as a source of human and animal food, dietary supplements and raw materials
• Cyanobacterial growth is favored in calm, nutrient-rich waters, and can lead to harmful blooms and toxin production with negative consequences
• Cyanobacteria can interfere with water treatment by producing cyanotoxins
• Euglenophyta (flagellates)


  Commonly found in freshwater, especially when rich in organic materials, with a few marine and endosymbiotic members<|>Many euglenids feed by phagocytosis, or strictly by diffusion<|>Euglenales have chloroplasts and produce their own food through photosynthesis
• Euglenids


  First defined by Otto Bütschli in 1884 as the flagellate order Euglenida, as an animal<|>Botanists subsequently created the algal division Euglenophyta; thus, they were classified as both animals and plants, as they share characteristics with both
• Euglenoids


  • Distinguished mainly by the presence of a type of cell covering called a pellicle, which are elastic structures of membranes that permit movement of the cell
• No evidence has been found of euglenids ever using sexual reproduction, which is one of the reasons they could no longer be classified as animals