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What Alga Is?

What Alga Is?. Chlorophyll bearing organisms with thylloid (having no True roots ., stems and leaves ). Word Origination Algae has about 3000 species & 2000 genera

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What Alga Is?

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  1. What Alga Is? Chlorophyll bearing organisms with thylloid (having no True roots., stems and leaves ). • Word Origination • Algae has about 3000species & 2000genera • Algae has world wide distribution from Europe - Pacific and Asia.( Arctic, Antarctic,North& South America).

  2. Occurrence & Habitat Been recorded from snow, hot springs, tide pools to rocky coasts or floating as masses of filaments or water blooms. • See Weeds are mostly found in Rocky Coasts • Euglena ,Diatoms&Anabaenafound inRiver & Ditches • Polycystis & Dinoflagellates found in Moist Places (Tree Trunks)

  3. History • Early reference found in Chinese Literature mentioned as TsaO • Greeks & Roman literature used words like Phycos & Fucus • Inhabitants of Hawaiiused it as food known as Limu.

  4. Classification • Algae classification is based on following bases. • Pigments • Reserve food products • Flagellation • Cell wall • Cell Structure

  5. Forms of Algae(W.h.Harvay) • Red Algae • Brown Algae • Green algae • Diatoms

  6. Morphology Algae are Eukaryotic except Blue Green Algae. Flagella Flagellaare found in all except Cyanophyta & Rhodophyta Three important points • Nature • Number • Positionof Flagella in primary Classification of Algae

  7. Cell Wall Made up of two materials Inner Water Insoluble Outer Pectic substances Most common material of inner layer is Cellulose In cell wall of Phaephytaalaginic & Fucinic acid are found whereas mucopeptide is present in cell wall of Blue-Green Algae. In some algae, walls contain definite Pores for Mucilage discharge & connections for protoplasmic connections.

  8. Plastids & Chromatophores • Double membrane structures are of two types Colored Chromatophores ColorlessLeucoplasts Plastids LeucoplastsChromatophores Chlorophyll a & b Chlorophyll b

  9. Pyrenoids • Protinaceous fibrils on or in the Chromatophore surface. • One in Chlamydomonas or many in Oedogonium • Store starch in green algae • Found in all except Cyanophyta • Arise De Novo or by Division of pre-existing cells.

  10. Golgi BodiesMitochondria ER • G-Complex here is known as • Dictyosomes. • Situated near Chromatophores, • Flagella, nucleus. • Exact function not defined • so far. • Absent in Cyanophyta. • Are present • Number & size vary. • Exact function is Respiratory related. • Absent in Cyanophyta • Present in Most Algae • System of tubules. • Ribosomes on outer Surface • Absent in Cyanophyta.

  11. Vacuoles Eye Spots (Stigma) • One or More Vacuoles. • Meant for Osmotic Relation & regulation of Solutes • Two Types • Contractile • Complex • Orange eye-spot located • Consist of Lipid Droplets present irregularly. • They are light sensitive photoreceptors. • It helps in orientation of motile Flagella.

  12. Ecology • The various sorts of algae play significant roles in aquatic ecology • Provide the food base for most marine food chains • In very high densities (so-called algal blooms) discolor the water and out compete, asphyxiate other life forms • Sea weeds have been recorded at depth of 300m. • Some are used as human food or harvested for useful substances such as agar, carrageenan, or fertilizer

  13. Nutrition Cell Chlorophyll Store light Energy CO2 + Water(Surrounding Environment)Sugars Chemical equation 6CO2+12H2O C6H12H6 +6O2+6H2O • Photoautotrophic • Holozoic • Parasitic • Heterotrophic

  14. Reproduction • Vegetative • Sexual • Asexual • Vegetative Reproduction Unicellular Cells Cell division Filamentous forms Fragments forms Fragmentation Example Blue Green Algae

  15. Asexual Reproduction Special cells types Replication of Organism Asexual Reproduction results in development & maintenance of stable population. • Sexual Reproduction • Sexual reproduction involves • Union of Cells(Plasmogamy) • Union of Nuclei(Karyogamy)

  16. Uses • Largest source of oxygen producer 83-87% of the total oxygen • Bio-diesel production . • There are also commercial uses of algae as agar • Some Cosmetics can come from micro algae as well • chemical dyes and coloring agents • Seaweeds are used as fertilisers and even food • Algae are used in wastewater treatment facilities

  17. Algae and symbioses lichens: A fungus is the host, usually with a green alga or a cyanobacterium as its symbiont Corals: algae known as zooxanthellae are symbionts with corals. Notable amongst these is the dinoflagellate Symbiodinium, found in many hard corals. Sponges: green algae live close to the surface of some sponges, for example, breadcrumb sponge (Halichondria panacea). The alga is thus protected from predators; the sponge is provided with oxygen and sugars which can account for 50 to 80% of sponge growth in some species.

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