Algae

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1. Algae

2. Unicellular Green Algae - Chlamydomonas Chlamydomonas reproduces by binary fission and produces flagellated zoospores for sexual reproduction Organisms such as Chlamydomonas are believed to be evolutionary ancestors of other species

3. Kingdom Protista The most ancient eukaryotic kingdom Protists include a variety of eukaryotic forms; they are mostly solitary, some colonial or multicellular , autotrophic, or heterotrophic and mostly aerobic Perhaps they are best defined as eukaryotes that are NOT fungi, animals, or plants 3

4. Classification of algae based on the types of pigments Taxonomic Group Photosynthetic Pigments Cyanobacteria chlorophyll a , chlorophyll c , phycocyanin, phycoerythrin Chloroxybacteria chlorophyll a , chlorophyll b Green Algae ( Chlorophyta) chlorophyll a , chlorophyll b , carotenoids Red Algae ( Rhodophyta) chlorophyll a , phycocyanin, phycoerythrin, phycobilins Brown Algae (Phaeophyta) chlorophyll a , chloorphyll c, fucoxanthin and other carotenoids Golden-brown Algae (Chrysophyta) chlorophyll a , chlorophyll c, fucoxanthin and other carotenoids Dinoflagellates (Pyrrhophyta) chlorophyll a , chlorophyll c , peridinin and other carotenoids Vascular Plants chlorophyll a , chlorophyll b , carotenoids

5. Chlorophyta Green Algae – Forms and examples A diverse group of fresh water algae but a few are marine forms The body may be unicellular and motile as in Chlamydomonas or colonial as in Volvox or filamentous as in Ulothrix and Spirogyra and may be plant like marine forms as in Fristschiella and Ulva The cells possess one to many chloroplasts in characteristic shapes in different examples. Photosynthetic pigments are chlorophyll a, chlorophyll b, carotenes and xanthophylls

6. Vegetative reproduction occurs by cell division, fragmentation and stolon formation Asexual reproduction occurs by the formation of akinites , zoospores or aplanospores Sexual reproduction involves isogamy or anisogamy or oogamy. Zygote is the only diploid structure in the life cycle. There is a regular alternation of haploid gametophytic and diploid sporophytic generations in the life cycle. Green Algae - Reproduction Zoospores: flagellates with eye-spot and contractile vacuole Aplanospores : non-flagellated cells with contractile vacuole Autospores : non-flagellated cells lacking contractile vacuole Terrestrial species predominantly form autospores

7. Filamentous Green Algae - Spirogyra Spirogyras are multi-cellular and all the cells of these organisms are haploid and cylindrical in shape Spirogyra cell wall is surrounded by mucilage The chloroplast in Spirogyra is wound spirally just inside the cell wall, central region of the cell is filled with vacuole , and the nucleus is suspended by threads of cytoplasm in the cell vacuole

8. Asexual reproduction in Spirogyra happens via the fragmentation of cells (below left) Sexual reproduction in Spirogyra is of two types, scalariform conjugation and lateral conjugation (below right) Reproduction in Spirogyra

9. Colonial Green Algae - Volvox

10. Rhodophyta ( Red Algae) forms Red algae are multi-cellular aquatic algae which exhibit a highly varied organization of the plant body Are commonly called 'red algae' due to the presence of a characteristic red pigment called phycoerythrin (red), which masks the color of other pigments like phycocyanin (blue) and chlorophyll (green) They are generally found attached to rocky stones. Some occur as total or semi parasites on the other algal plants