BOT201 2004 PHAEOPHYTE Lecture

BOT201 2004 PHAEOPHYTE Lecture - Kingdom Protista Kingdom...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Kingdom Protista Kingdom Brown algae Green algae Simple Eukaryotes Red algae J e Kingdom Protista Kingdom Division Phaeophyta, first brown plants first land plants evolve • Recent plants, ~500 mya • “Standard” eukaryote cells No multinucleate cells Motile cells usual • Non-standard chloroplasts Things we will cover for brown algae • General features - defining characteristics • Morphological lineages – - use morphology to anticipate evolution - reveal variations in life history & gametes • Ecology – understanding interactions with environment and other species • Commercial interests – exploit ecology & life history • Evolution – diversity & change over time General features General Ocean lovers Ocean Forests 2,000 species (60 in HI oceans) 250+ genera (29 in HI) Morphological Range: filaments to complex multicell organisms Recently arrived eukaryotes well suited to coastal habitats Intertidal Reef algae Natives and invasives Subtidal Diversity Diversity General features Pigments Pigments photosynthesis Storage Products Products Growth • Chlorophyll a • Chlorophyll c • Fucoxanthin Others • Carotenoids • UV absorbing molecules Photosynthesis 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 a, Chl a, c a, fucoxanthin Chlorophyll a & c Tetrapyrrole Ring Phytol Chain of Chl a missing in Chl c General features Pigments Pigments photosynthesis Storage Products Products • Laminarin • Mannitol Sugar (C) Sugar (C) Starch (C) (C) • Every cell can divide Growth • Chlorophyll a • Chlorophyll c • Fucoxanthin • Multicellular organisms: Fragments regrow • True tissues Others • Carotenoids • UV absorbing molecules Cell wall structure Cell Two essential parts: • fibers of cellulose (rigid), a glucose polymer • gels of polysaccharides (flexible) as ALGINATE Cell wall structure Cell Two essential parts: • fibers of cellulose (rigid), a glucose polymer • gels of polysaccharides (flexible) as ALGINATE “Copolymer” blocks of sugars Guluronic (G) Mannuronic (M) General features General What is in a typical phaeophyte cell? • Unusual membrane system around chloroplast and nucleus • Pyrenoid large, stalked and surrounded by laminarin starch • Chloroplasts have grana Evolution of eukaryotes Xenogenous hypothesis Xenogenous heterotrophs Simple cells phagocytosis Autotrophs - green and red algae Mereschowsky, 1905; 1910 General features General How are phaeophyte cells unusual? • “New” membranes around chloroplast & nucleus First step: Second step: Repeated endosymbioses Second eukaryote Life History as a Life “Strategy” Zygotic Meiosis Life History Gamete DOES NOT OCCUR IN BROWN ALGAE Zygote Gamete Meiosis Meiosis is associated with Zygote Germination Morphological lineages Morphological • Evaluate adult form to gain insight in possible evolutionary processes. • Step-by-step acquisition of new traits via genetic change. • Examine reproductive cells and other characters as additional data. • Useful means to construct evolutionary hypotheses to test with molecular data. Life History as a Life “Strategy” Meiosis is associated with Spore Production Growth & Growth morphology Ectocarpus Genetic change Morphological Lineage #1 Order Ectocarpales All cells appear virtually identical internally Hincksia Evolution has taken a simple shape to more complex but related forms: forms • Multi filamentous genera Ralfsia Diversity Order Ectocarpales Ectocarpus Ralfsia Hincksia sp Life history by Life observation Ectocarpus Same motile cell has 2 behaviors ? Where’s meiosis ? Life History as a Life “Strategy” recognition zygote germling isogametes Ectocarpus sp. mitosis mitosis meiosis spores adults germlings mitosis Life History as a Life “Strategy” Meiosis is associated with Spore Production Reproduction Reproduction and gametes 2 Gametes – opposite strains always fuse Equally sized gametes Isogamy Unequal gametes Anisogamy Zygote – diploid cell via fusion of gametes Egg & sperm gametes Oogamy egg Minimal diversity Minimal in gamete shape… • But flagella of swimming cells are unequal in length and HAIRY Equal length flagella Iso kont Swimming gametes have 2 flagella like greens Unequal length flagella Hetero kont Laterally inserted Minimal diversity Minimal in gamete 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 ? Diversity Tropical Orphans Scytosiphon sp. Hydroclathrus sp. Rosenvingea sp. Colpomenia sp Spatoglossum sp. Growth & Growth morphology 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 Diversity Diversity Order Dictyotales Dictyota sp. Padina sp. Life History as a Life “Strategy” recognition zygote oogametes meiosis tetra spores Dictyota mitosis spores mitosis adults germlings Life History as a Life “Strategy” Meiosis is associated with Spore Production Growth & Growth morphology Morphological Lineage #3 Order Laminariales Laminaria Alaria Evolution has taken a simple shape: • constrained into lamina • large sporophyte generations Macrocystis Diversity Diversity Order Laminariales Ecology Ecology Kelp forests sustain coastal diversity epiphytic pelagic benthic understory Life History as a Life “Strategy” Macrocystis Life History as a Life “Strategy” Ecklonia cava Spores Egg and sperm Growth & Growth morphology Ectocarpus Morphological Lineage # 4 Order Fucales Dictyopteris sp Sargassum obtusifolium Sargassum thunbergii Gunma Japan Diversity Order Fucales Sargassum cristaefolium Guam Life History as a Life “Strategy” Meiosis is associated with Gamete Production Life History as a Life “Strategy” juvenile recognition zygote Sargassum sp. oogametes adult meiosis vegetative cell detail Life History as a Life “Strategy” 1 free living entity Cells must pass through this cycle • to add new genetic individuals to population Ecology of Hawaiian Reef Algae. w Biomass 6000 5000 4000 3000 2000 1000 0 Frondose Algae of Wakiki, by M S. Doty 1969 ,m Dictyotales, o Fucales representatives on reefs et wt, g/m 2 Du 1 4 250 ra t 7 200 ion 9 150 of 12 100 stu 13 17 0 50 dy eef R r , ion eg m fro m o re sh All browns were native species Most abundant biomass near shore ...
View Full Document

Ask a homework question - tutors are online