Transcript GA - Oswego
DOMAIN EUKARYA KINGDOM PROTISTA II Multicellular Protista (Red, Brown, & Green algae) Major primary producers in aquatic systems Provide home for microorganisms and fishes The red and brown algae are primary multicellular and mostly marine organisms Green algae contain many unicellular and mostly freshwater Cellulose is found in the cell wall of the three phyla among others Green algae store carbs as starch in the chloroplasts Red algae store food as floridean & brown algae as laminarin, outside the chloroplast Red algae lack flagella Origins of chloroplast in Algae Chloroplast of red algae resembles that of Cyanobacteria [Chl(a), carotenoid, phycobilins] Chloroplasts of green algae, Euglenoids, & plants resemble that of Prochloron [Chl(a), (b), carotenoids] Chloroplast of brown algae, Chrysophytes, & diatoms have the same origin! All have Chl a, c, & fucoxanthin. BA 1. Brown Algae: Phylum Phaeophyta Prefer cold agitated, well aerated water (temperate regions) Common on rocky shores (intertidal zones) They have a complex anatomy & morphology* Cell wall contain cellulose & alginic acid (not in other algae) Reserve food is Laminarin Range from small filamentous to large multicellular organisms BA Examples of brown algae that grow in intertidal (shoreline) zone Stipe Rockweed Holdfast Kelp BA The giant kelps - Are examples of brown algae that grow in deep clear waters (up to 30m) - Brown & red algae provide food (SE Asia) BA Blade Stipe Kelp, giant seaweed Holdfast Brown Algae: Ectocarpus Plurilocular Sporangium http://www.dipbot.unict.it/sistematica/Ectoc_pl.html 2. Green Algae (Phylum Chlorophyta) Include unicellular, colonial, and multicellular organisms They are resilient & survive many types of disturbances Mainly freshwater organisms Closely related to plants because: Have chlorophylls a, b, & carotenoids Store reserve food as starch in the chloroplast Cell wall contains cellulose GA Class Chlorophyceae The only living organisms in which cell division involves a phycoplast (Cleavage furrow) Zygotic meiosis Mostly freshwater organisms Produce red, orange, & green snow Have flagellated and nonflagellated forms Chlorophyceae Phycoplast Cleavage furrow Cell plate It insures that cleavage furrow passes between the daughter cells GA Motile Unicellular Chlorophyceae Chlamydomonas: Unicellular Move by means of two flagella* Asexual reproduction: haploid cells divide by mitosis producing up to 16 cells Sexual reproduction* Chlamedomonas GA Motile Unicellular Chlorophyceae Sexual reproduction induced by nitrogen starvation GA Motile Colonial Chlorophyceae - A colony is an aggregate of independent cells - Daughter colonies detach & form new colonies - Cells’ flagella beat in a coordinate fashion Motile Colonial Chlorophyceae http://www.botany.hawaii.edu/Bot480/Volvocale s%20table%20of%20web%20links.htm GA Nonmotile Unicellular Chlorophyceae algae.tcoalternativefuels.com/about-algae Example: Chlorella: Lacks flagella, eyespots, and contractile vacuoles Live in fresh, salt water, and in soil Reproduce only asexually (mitosis) Nonmotile Unicellular Chlorophyceae Chlorococcum oleofaciens Filled with asexual spores GA Nonmotile colonial Chlorophyceae: http://protist.i.hosei.ac.jp/PDB/Images/Chlorophyta/Hydrodictyon/ Example Hydrodictyon (water net) in ponds, lakes, and streams GA Filamentous Chlorophyceae: Example Oedogonium* Filamentous green algae are more complex Each cell has a specific function Cells are connected by plasmodesmata like plants Sexual reproduction is oogamous, meiosis is zygotic O. gracilius OOgonium http://vis-pc.plantbio.ohiou.edu/Hocking/photos/Oed.html GA Class Ulvophyceae: Examples: Cladophora and Ulva* Marine organisms The only green algae with sporic meiosis Unlike other green algae, they rarely form dormant zygospores Ulvophyceae: Chladophora http://www.uwinnipeg.ca/~simmons/cladoph.htm http://www.gettysburg.edu/~rcavalie/bda_i/091.html GA Ulvophyceae Sea lettuce (Ulva) The thallus is two cells thick and up to a meter long GA Class Charophyceae Unicellular, filamentous, and parenchymatous genera Zygotic meiosis a. Spirogyra: (freshwater habitats) GA Conjugation Union of two cells during which genetic material is exchanged No flagellated stage in its life cycle Asexual reproduction by fragmentation Sexual reproduction via conjugation This forms a zygote which undergo meiosis GA Plants evolved from an extinct member of Charophycease (Coleochaetales & Charales)! b. Chara (stoneworts) resembles ancestor of land plants! Like plants they have apical growth (differentiated into nodal & internodal regions) Produce antheridia & archegonia Sperms are flagellated Similar cytokinesis http://www.aquaweed.com/chara.htm Cytokinesis in Charophyceae Phragmoplast found in all green algae except chlorophyceae C. In simple Charophytes: Cytokinesis occurs by furrowing D. In advanced Charophytes: like plants (cell plate & plantlike phragmoplast. Spindles not persistent RA 3. Red Algae: Phylum Rhodophyta Marine organisms, common to tropical & warm water Differ from other algae and plants in that: Contain phycobilin pigments (red), Chloroplasts do not form grana stacks Food reserves is floridean outside the chloroplast Cell wall contain cellulose (galactans), calcium carbonate, lack plasmodesmata Almost all red algae are multicellular Have no flagellated forms The source of agar (mucilage material in cell wall) RA Red Algae: Bonnemaisonia asparagoides http://www.horta.uac.pt/species/Algae/Bonnemaisonia_asparagoides/Bonnemaisonia_asparagoides.htm RA Red Algae: Bonnemaisonia spp http://www.horta.uac.pt/species/Algae/Bonnemaisonia_asparag oides/Bonnemaisonia_asparagoides.htm RA Red Algae: Gelidium amansii http://www.botany.uwc.ac.za/presents/Seashore2/75.htm RA Red Algae: Amphiroa carolline http://www.globaldialog.com/~jrice/algae_page/bush_coralline.htm RA Can be up to 1 meter long but generally smaller and more delicate than brown algae Chondrus crispus