present. Two laterally inserted unequal flagella are present. Among these one is whiplash and another is tinsel. Although sexual reproduction ranges from isogamy to oogamy, Most of the forms show oogamous type.
Alternation of generation is present (isomorphic, heteromorphic or diplontic). Examples for this group include Sargassum, Laminaria, Fucus and Dictyota. Rhodophyceae Members of this group include ‘ Red algae ’ and are mostly marine. The thallus is multicellular, macroscopic and diverse in form.
Porphyridium is the unicellular form. Filamentous ( Goniotrichum ) ribbon like ( Porphyra ) are also present. Corallina and Lithothamnion are heavily impregnated with lime and form coral reefs. Apart from chlorophyll a, r-phycoerythrin and r-phycocyanin are the photosynthetic pigments.
Asexual reproduction takes place by means of monospores, neutral spores and tetraspores. The storage product is floridean starch. Sexual reproduction is oogamous. Male sex organ is spermatangium which produces spermatium.
Female sex organ is called carpogonium. The spermatium is carried by the water currents and fuse with egg nucleus to form zygote. The zygote develops into carpospores. Meiosis occurs during carpospore formation.
Alternation of generation is present. Examples for this group of algae include Ceramium, Polysiphonia, Gelidium, Cryptonemia and Gigartina. Table . : Economic importance of Algae Name of the Algae Economic importance Beneficial activities Chlorella, Laminaria, Sargassum, Ulva, Enteromorpha Food Gracilaria, Gelidiella, Gigartina Agar Agar – Cell wall material used for media preparation in the microbiology lab.
Packing canned food, cosmetic, textile paper industry Chondrus crispus Carrageenan – Preparation of tooth paste, paint, blood coagulant Laminaria, Ascophyllum Alginate – ice cream, paints, flame proof fabrics Laminaria, Sargassum, Ascophyllum, Fucus Fodder Diatom ( Siliceous frustules ) Diatomaceous earth– water filters, insulation material, reinforcing agent in concrete and rubber. Lithophyllum, Chara, Fucus Fertilizer Chlorella Chlorellin -Antibiotic Chlorella, Scenedesmus, Chlamydomonas Sewage treatment, Pollution indicators Harmful activity Cephaleuros virescens Red rust of coffee . . Economic Importance The Economic importance of Algae is given in Table .
A green alga Botryococcus braunii is employed in Bio- fuel production. Algae in Health care Kelps are the rich source of Iodine Chlorella is used as