Biology Lecture 3/2/15Stramenopila- Phylum Bacllariophyta: Diatoms- Phylum Phaeophyta: Brown algaeSuper group Chromalveolata (SAR)Clade Stramenopila- Most photosynthetic (1 exception)- Characterized by 2 contrasting flagella: -hairy (tinsel) flagellum – shorter, smooth flagellumStramenopila 4 phyla1. Water molds (Oomycetes/oomycota)2. Diatoms (Bacillariophyta)3. Golden algae (chrysophyla)4. Brown algae (phaeophyta)Super group chromalveolata clade stramenopilaDiatoms: (phylum Bacillariophyta)- Freshwater, marine, soil- Distinguished by 2- part SiO2 shell: frustule- Possess chlorophyll a and c- Considerable ecological, geological, economic importance2 groups of diatoms based on frustule morphology: centric = centrales and pennate = pennalesCentric = centrales: radial symmetryPennate = pennales: bilateral symmetryRaphe: longitudinal opening in pennales- Pennate diatoms are benthic and move via mucilage secretions from rapheDiatoms ecological/industrial valueEcological- O2 production: ~ 40% atmospheric O2 - Most abundant eukaryotic life formGeological:- Frustules decomposition resistant diatomiteBrown Algae:- Photoautrophic: most marine- Complex, multicellular thalli- -filaments –macrophyicBrown algae life cycle- Some display distinctive “alternation of generations”- Two distinct multicellular stages in life cycle: sporophyte and gametophyteSporophyte: DiploidGametophyte: HaploidAlginic acid (an emulsifier) use: charcoal, cosmetics, cheese, paint, rubber, etc.Water molds: oomycota- Fresh water/ marine treestrial habitats- Parasitic or saprophytic- Formerly classified as fungiNon-fungal features:- Cell walls with cellulose (fungi possess chitin)- Flagellate cells in life cycle (fungi lack flagellated cells)Filamentous growth resembles fungal hyphate during feed phaseTerrestrial oomycetes- Severe plant parasitesDhytopthora- “Potato late blight” and “sudden oak death”All other stramenopiles are photosynthetic2 types of chlorophyll that stramenopiles possess: chlorophyll a and chlorophyll cChlorophyll a: typical of all oxygenic photoautotrophsChlorophyll c: imparts golden/brownish colorPointers for exam 21. Classification and phylogenetic relationships- Chromalveolata includes 2 clades and 7 phyla2. Processes- Nitrogen fixation, red tide, plasmodium life cycle3. Terminology- Mitosome, heterkontous, kinetosomes5 super groups of Eukarya: Excavata, Chromalveolata, Rhizaria, Archaeplastida, UnikontaSuper group Excavata: Diplomonads, parabasalids, euglenozoansDiplomonads: parasites, Giardina, Parabasalids: parasites/mytualists, Trichomonas, TrichonymphaEuglenozoans: Kinetoplastids and EuglenidsKinetoplastids: Parasites, Kinetosomes, PlasmodiumEuglenids: free living, mixotrophicChromalveolata: Chlorophyll c, cytoplasmic aveoliRizaria: Specialized cytoplasmic extensionsArchaeplastida: primary endosymbiosis descendants, 2 membrane plastidsUnikonta: flagellated cells with single posterior flagellum1. Stramenopila - Phaeophyla2. Super group Rhizaria3. Super group Archaeplastida- Evolutionary orgins: 1° endosymbiosisSuper group Rhizaria: All marine, planktonic or benthic; heterotrophs, formally grouped with the amoeba (unikonta), super group status based principally on molecular data Super group Archaeplastida- Direct decedents of primary endosymbiotic events giving rise to photosynthetic eukarotesRhodophyta- Red algae- Marine, some freshwater- Unicellular, filamentous/branching, parenchymous - No flagellated stages- Ps Pigment: Phycoerythrin - Absorbs blue/green wavelengths- “understory” component of marine ecosystemsRhodophyta “coralline forms”- CaCO3 (calcium carbonate) in tropical oceans- Reef formation, substrate stabilizationSuper group Archaeplastida: Green algaeChlorophyceae and Charpryceae- Typically treated as class of phylum chlorophyta- Unifying features: Ps pigments Chlorophyll a and b.Energy storage: starch- Includes progenitor group of plantsChlorophyceae: Most diverse/abundant of green algae and important freshwater producers There are 7000 described species4 evolutionary/morphological groups of chlorophyceae: flagellated cells (unicellular/colonial), filamentuous/paraenchymous thalli (non-flagellated), ooenocytic “Super cells”Amoeba and relatives- Amoeba and relatives formally places in one Phylum: Amoeboza- Slime molds formerly classified as member of Kingdom Fungi- Heterotorphic (exception chlorarachlophytes)- Aquatic-terrestral- 2 groups loosely related by cellular extensions for feeding/mortility- Axopodia pseudopodiaCencozoa “Foraminiferans”: secrete calcium carbonate (CaCO3) shell, and is important component of marine planktonRdiolaria “radiolarians”: also marine planktonic, secrete ornate, SiO2 shell, axopodia distinguished by reinforcing protein or microtubulesNew terms/features introduces in oomycete life cycleOogonium: unicellular organ; egg (oocyte) formationAntheridium: Unicellular/multicellular organ; sperm (spermatocyte) formationOospore: Zygote formed by syngamy of similar gametesZoosporangium: unicellular organ, motive asexual propagule (zoospore) formationQuizlet link: