Kingdom Protistaprotista Brown Algae Green Algae
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KingdomKingdom ProtistaProtista Brown algae Green algae Simple Eukaryotes Red algae J e KingdomKingdom ProtistaProtista DivisionDivision Phaeophyta,Phaeophyta, first brown plants land plants evolve •Recentplants, ~500 mya • “Standard” eukaryote cells No multinucleate cells Motile cells usual • Non-standard chloroplasts ThingsThings wewe willwill covercover forfor brownbrown algaealgae •• GeneralGeneral featuresfeatures -- definingdefining characteristicscharacteristics •• MorphologicalMorphological lineageslineages –– -- useuse morphologymorphology toto anticipateanticipate evolutionevolution -- revealreveal variationsvariations inin lifelife historyhistory && gametesgametes •• EcologyEcology –– understandingunderstanding interactionsinteractions withwith environmentenvironment andand otherother speciesspecies •• CommercialCommercial interestsinterests –– exploitexploit ecologyecology && lifelife historyhistory •• EvolutionEvolution –– diversitydiversity && changechange overover timetime GeneralGeneral featuresfeatures OceanOcean loverslovers 2,0002,000 speciesspecies (60(60 inin HIHI oceans)oceans) Ocean Forests 250+250+ generagenera (29(29 inin HI)HI) MorphologicalMorphological RangeRange:: filaments to complex multicell organisms Intertidal RecentlyRecently arrivedarrived Subtidal eukaryoteseukaryotes -- Reef algae wellwell suitedsuited toto Natives and invasives coastalcoastal habitatshabitats Natives and invasives DiversityDiversity GeneralGeneral featuresfeatures PigmentsPigments -- StorageStorage GrowthGrowth photosynthesis ProductsProducts • Chlorophyll a • Chlorophyll c • Fucoxanthin OthersOthers • Carotenoids • UV absorbing molecules PhotosynthesisPhotosynthesis && PigmentsPigments sunlight • Light energy is harvested by the cell • Only specific colors are absorbed • Other colors are reflected back to your eye thylakoids Chl a, c Chl a, c fucoxanthin Chlorophyll a & c Tetrapyrrole Ring Phytol Chain of Chl a missing in Chl c GeneralGeneral featuresfeatures PigmentsPigments -- StorageStorage GrowthGrowth photosynthesis ProductsProducts • Every cell can divide • Chlorophyll a • Laminarin • Multicellular • Chlorophyll c Starch (C) organisms: • Fucoxanthin • Mannitol Sugar (C) Fragments regrow • True tissues Others • Carotenoids • UV absorbing molecules CellCell wallwall structurestructure Two essential parts: • fibers of cellulose (rigid), a glucose polymer • gels of polysaccharides (flexible) as ALGINATE CellCell wallwall structurestructure Two essential parts: • fibers of cellulose (rigid), a glucose polymer • gels of polysaccharides (flexible) as ALGINATE “Copolymer” blocks of sugars Guluronic (G) Mannuronic (M) GeneralGeneral featuresfeatures WhatWhat isis inin aa typicaltypical phaeophytephaeophyte cell?cell? • Unusual membrane system around chloroplast and nucleus • Pyrenoid large, stalked and surrounded by laminarin starch • Chloroplasts have grana EvolutionEvolution ofof eukaryoteseukaryotes XenogenousXenogenous hypothesishypothesis heterotrophs Simple cells phagocytosis Autotrophs - green and red algae Mereschowsky, 1905; 1910 GeneralGeneral featuresfeatures HowHow areare phaeophytephaeophyte cellscells unusual?unusual? •“New” First step: membranes around chloroplast & nucleus Second step: Second eukaryote RepeatedRepeated endosymbiosesendosymbioses LifeLife HistoryHistory asas aa “Strategy“Strategy”” ZygoticZygotic MeiosisMeiosis LifeLife HistoryHistory Gamete DOESDOES NOTNOT OCCUROCCURZygote ININ BROWNBROWNGamete ALGAEALGAE Meiosis MeiosisMeiosis isis associatedassociated withwith ZygoteZygote GerminationGermination MorphologicalMorphological lineageslineages •• EvaluateEvaluate adultadult formform toto gaingain insightinsight inin possiblepossible evolutionaryevolutionary processes.processes. •• StepStep--byby--stepstep acquisitionacquisition ofof newnew traitstraits viavia geneticgenetic change.change. •• ExamineExamine reproductivereproductive cellscells andand otherother characterscharacters asas additionaladditional data.data. •• UsefulUseful meansmeans toto constructconstruct evolutionaryevolutionary hypotheseshypotheses toto testtest withwith molecularmolecular data.data. LifeLife HistoryHistory asas aa “Strategy”“Strategy” MeiosisMeiosis isis associatedassociated withwith SporeSpore ProductionProduction GrowthGrowth && morphologymorphology Morphological Lineage #1 Order Ectocarpales Genetic change All cells appear virtually identical - internally Ectocarpus Hincksia Evolution has taken a simple shape to more complex but related forms:forms Ralfsia • Multi filamentous genera DiversityDiversity Order Ectocarpales Ectocarpus Ralfsia Hincksia sp LifeLife historyhistory byby observationobservation Ectocarpus Same motile cell has 2 behaviors ? Where’sWhere’s meiosismeiosis ?? LifeLife HistoryHistory asas aa “Strategy”“Strategy” recognition zygote germling isogametes mitosis meiosis Ectocarpus sp. mitosis spores germlings mitosis adults LifeLife HistoryHistory asas aa “Strategy”“Strategy” MeiosisMeiosis isis associatedassociated withwith SporeSpore ProductionProduction ReproductionReproduction andand gametesgametes Equally sized gametes 2 Gametes – opposite strains always fuse Isogamy Unequal gametes Anisogamy Zygote – diploid cell via fusion of gametes Egg & sperm gametes Oogamy egg MinimalMinimal diversitydiversity in gamete shape… Equal length flagella in gamete shape… Iso kont Swimming gametes have 2 flagella like greens • But flagella of swimming cells are unequal in length and HAIRY Unequal length flagella Hetero kont Laterally inserted MinimalMinimal diversitydiversity inin gametegamete shape…shape… These males gametes show the limited diversity among brown algae Reds – spermatium Greens – biflagellate to stephanokont males Minimal diversity in spore shape • Most brown algal spores swim •2 flagella • Settlement ? DiversityDiversity TropicalTropical OrphansOrphans Scytosiphon sp. Hydroclathrus sp. Rosenvingea sp. Colpomenia sp Spatoglossum sp. GrowthGrowth && morphologymorphology Morphological Lineage #2 Order Dictyotales Dictyota Dictyopteris Evolution has taken a simple filament: Multiseriate tissues create sheets or blades From apical cell or meristem areas Padina DiversityDiversity Order Dictyotales Dictyota sp. Padina sp. LifeLife HistoryHistory asas aa “Strategy”“Strategy” recognition meiosis zygote tetra oogametes spores Dictyota spores mitosis germlings mitosis adults LifeLife HistoryHistory asas aa “Strategy”“Strategy” MeiosisMeiosis isis associatedassociated withwith SporeSpore ProductionProduction GrowthGrowth && morphologymorphology Morphological Lineage #3 Order Laminariales Laminaria Alaria Evolution has taken a simple shape: • constrained into lamina • large sporophyte generations Macrocystis DiversityDiversity Order Laminariales EcologyEcology KelpKelp forestsforests sustainsustain coastalcoastal diversitydiversity epiphytic pelagic benthic understory LifeLife HistoryHistory asas aa “Strategy”“Strategy” Macrocystis LifeLife HistoryHistory asas aa “Strategy”“Strategy” Ecklonia cava Spores Egg and sperm GrowthGrowth && morphologymorphology Morphological Lineage # 4 Order Fucales Ectocarpus Dictyopteris sp Sargassum obtusifolium DiversityDiversity Sargassum thunbergii Gunma Japan Order Fucales Sargassum cristaefolium Guam LifeLife HistoryHistory asas aa “Strategy”“Strategy” MeiosisMeiosis isis associatedassociated withwith GameteGamete ProductionProduction LifeLife HistoryHistory asas aa “Strategy”“Strategy” juvenile recognition zygote adult Sargassum sp. oogametes vegetative meiosis cell detail LifeLife HistoryHistory asas aa “Strategy”“Strategy” 11 freefree livingliving entityentity CellsCells mustmust passpass throughthrough thisthis cyclecycle • to add new genetic individuals to population EcologyEcology ofof HawaiianHawaiian ReefReef Algae.Algae. Frondose Algae of Wakiki, B by M S. Doty 1969 i o 6000 m a s 5000 s - 4000 w e 3000 t w 2000 t , g 1000 / m 2 0 1 250 D 4 u 7 200 e ra 150 or tio 9 sh n 12 100 m o 50 fro f 13 m st 17 0 n, ud gio y re Dictyotales, , m ef o Re Fucales All browns were native species representatives on reefs Most abundant biomass near shore.