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Multicellular Protista (Red, Brown, Multicellular Protista (Red, Brown, & Green algae)& 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 AlgaeOrigins 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.
1. 1. Brown Algae: Phylum Brown Algae: Phylum PhaeophytaPhaeophyta
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
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
Brown Algae: Brown Algae: EctocarpusEctocarpus
http://www.dipbot.unict.it/sistematica/Ectoc_pl.html
Plurilocular Sporangium
2. Green Algae (Phylum 2. Green Algae (Phylum Chlorophyta)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, & carotenoidsStore reserve food as starch in the chloroplastCell wall contains cellulose
Class ChlorophyceaeClass 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
GA
Chlorophyceae PhycoplastChlorophyceae Phycoplast
It insures that cleavage furrow passes between the daughter cells
Cell plateCleavage furrow
Motile Unicellular Motile Unicellular ChlorophyceaeChlorophyceae
Chlamydomonas: Unicellular Move by means of two flagella Asexual reproduction: haploid cells divide
by mitosis producing up to 16 cells Sexual reproduction
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
GA
Motile Colonial Chlorophyceae
http://www.botany.hawaii.edu/Bot480/Volvocales%20table%20of%20web%20links.htm
Nonmotile Unicellular Nonmotile Unicellular ChlorophyceaeChlorophyceae
Example: Chlorella: Lacks flagella, eyespots, and contractile vacuoles
Live in fresh, salt water, and in soil Reproduce only asexually (mitosis)
GA
algae.tcoalternativefuels.com/about-algae
Nonmotile Unicellular ChlorophyceaeNonmotile Unicellular Chlorophyceae
Chlorococcum oleofaciensChlorococcum oleofaciensFilled with asexual sporesFilled with asexual spores
Nonmotile colonial Nonmotile colonial Chlorophyceae:Chlorophyceae:
Example Hydrodictyon (water net) in ponds, lakes, and streams
GA
http://protist.i.hosei.ac.jp/PDB/Images/Chlorophyta/Hydrodictyon/
Filamentous Chlorophyceae: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
GA
Class Ulvophyceae:Class Ulvophyceae:
Examples: Cladophora and Ulva* Marine organisms The only green algae with sporic meiosis Unlike other green algae, they rarely form
dormant zygospores
GA
Ulvophyceae:Ulvophyceae: Chladophora Chladophora
http://www.gettysburg.edu/~rcavalie/bda_i/091.html
http://www.uwinnipeg.ca/~simmons/cladoph.htm
Class CharophyceaeClass Charophyceae
Unicellular, filamentous, and parenchymatous genera
Zygotic meiosis a. Spirogyra: (freshwater habitats)
GA
No flagellated stage in its life cycle Asexual reproduction by fragmentation Sexual reproduction via conjugation This forms a zygote which undergo meiosis
Conjugation
Union of two cells during which genetic material is exchanged
GA
Plants evolved from an extinct member of Plants evolved from an extinct member of Charophycease (Coleochaetales & Charales)!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
GA
Cytokinesis in CharophyceaeCytokinesis in Charophyceae
C. In simple Charophytes: Cytokinesis occurs by furrowing
D. In advanced Charophytes: like plants (cell plate & plant-like phragmoplast. Spindles not persistent
Phragmoplast found in all green algae except chlorophyceae
3. Red Algae: Phylum 3. Red Algae: Phylum RhodophytaRhodophyta
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 chloroplastCell 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: Red Algae: Bonnemaisonia asparagoidesBonnemaisonia asparagoides
RA
http://www.horta.uac.pt/species/Algae/Bonnemaisonia_asparagoides/Bonnemaisonia_asparagoides.htm
Red Algae: Red Algae: Bonnemaisonia sppBonnemaisonia sppRA
http://www.horta.uac.pt/species/Algae/Bonnemaisonia_asparagoides/Bonnemaisonia_asparagoides.htm
Red Algae: Red Algae: Amphiroa carollineRA
http://www.globaldialog.com/~jrice/algae_page/bush_coralline.htm