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,a, cc Chl a,a, cc 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 Ectocarpus Genetic change All cells appear virtually identical - internally
Hincksia
Evolution has taken a simple shape to more complex but related forms:forms • Multi filamentous genera Ralfsia DiversityDiversity Order Ectocarpales
EctocarpusEctocarpus
Hincksia sp
RalfsiaRalfsia 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 ? . sp. sp
Spatoglossum Hydroclathrus sp.
Rosenvingea sp.
Scytosiphon Orphans Orphans sp Diversity Tropical Diversity Tropical Colpomenia GrowthGrowth && morphologymorphology Morphological Lineage #2 Order Dictyotales
Dictyota
Evolution has taken a simpleDictyopteris 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
Evolution has taken a simple shape: Alaria • 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