Prepared by : Km. Monika Balmiki KV GANGTOK

The study of ALGAE is called “Phycology” The study of ALGAE is called “Phycology” 1. Chlorophyl- bearing plants, 2. Thalloid, 3. Autotrophic & Aquatic.

HABITATS A)Aquatic ( Fresh water & marine) Moist stones, Soils and Wood. stones, Soils and Wood. B) Association with Fungi e.g. Lichen and animals e.g. Sloth bear animals e.g. Sloth bear C) Marine forms are Sea Weeds D) Fresh water Algae – Microscopic, Unicellular e.g. Chlamydomonas – Microscopic, Unicellular e.g. Chlamydomonas - Colonial forms e.g. Volvox - Colonial forms e.g. Volvox - Filamentous forms e.g. Ulothrix & Spirogyra. - Filamentous forms e.g. Ulothrix & Spirogyra.

REPRODUCTION Vegetative – by fragmentation. Fragments Vegetative – by fragmentation. Fragments develops into thallus. develops into thallus. Asexual - produce different type of spores Asexual - produce different type of spores (zoospores) (zoospores) - Zoospores – Flagellated motile - Zoospores – Flagellated motile and germination gives rise to new and germination gives rise to new plants. plants.

Sexual Reproduction – fusion of two gemets Sexual Reproduction – fusion of two gemets 1. Isogamous – Flagellated similar in size e.g. chlamydomonas e.g. chlamydomonas - Non-flagellated but similar in - Non-flagellated but similar in size e.g. spirogyra. size e.g. spirogyra. 2. Anisogamous – two gemets dissimilar in size e.g. chlamydomonas. e.g. chlamydomonas. 3. Oogamous - Fusion between one large, non-motile – female gemete. non-motile – female gemete. smaller motile- male gamete smaller motile- male gamete e.g. Volvox, Fucus. e.g. Volvox, Fucus.

IsogamousAnisogamous Oogamous

CLASSES OF ALGAE The Algae are divided into three mail Classes: The Algae are divided into three mail Classes: 1. Chlorophyceae 2. Phaeophyceae 3. Rhodophyceae

CHLOROPHYCEAE ( Green Algae) Plant Body - unicellular, Colonial or Plant Body - unicellular, Colonial or Filamentous Filamentous Rigid Cell Wall – Inner layer – Cellulose Rigid Cell Wall – Inner layer – Cellulose - Outer layer – Pectose - Outer layer – Pectose Green due to chlorophyll a & b Green due to chlorophyll a & b Definite chloroplasts – Discoid, Plate-like reticulate, Definite chloroplasts – Discoid, Plate-like reticulate, cup- shaped,spiral or ribbon-shaped cup- shaped,spiral or ribbon-shaped Storage bodies - Pyrenoids, located in the Storage bodies - Pyrenoids, located in the chloroplasts. Store food in the chloroplasts. Store food in the form of oil droplets form of oil droplets

VOLVOX CHLAMYDOMONAS ULVA

Chlorophyceae -Reproduction The Sex organs are always unicellular The Sex organs are always unicellular 1. Vegetative – Fragmentation(spores) 2. Asexual Reproduction – Flagellated zoospores 3. Sexual Reproducion – isogemous, anisogemous and anisogemous and oogamous oogamous

Phaeophyceae (Brown Algae) Marine habitats Marine habitats Plant body attached to the substratum by a Hold fast, Stalk –Stipe, Leaf Like- Photosynthetic organ – Frond Plant body attached to the substratum by a Hold fast, Stalk –Stipe, Leaf Like- Photosynthetic organ – Frond Golden brown – Xanthophyll pigment fucoxanthin in their chromotophores. Addition to chlo.a, chlo.c and carotenoids. Golden brown – Xanthophyll pigment fucoxanthin in their chromotophores. Addition to chlo.a, chlo.c and carotenoids. Accumulation of reserve food as fats and oil rather then starch. Accumulation of reserve food as fats and oil rather then starch. The cellulosic wall covered by algin The cellulosic wall covered by algin Centrally located vacuole and nucleus. Centrally located vacuole and nucleus.

LAMINARIADICTYOTA SARGASSUM

Phaeophyceae- Reproduction Vegetative reproduction – Fragmentation Vegetative reproduction – Fragmentation Asexual Reproduction - biflagellate Asexual Reproduction - biflagellate zoozpores (two unequal) zoozpores (two unequal) Sexual Reproduction - Isogamous, Sexual Reproduction - Isogamous, anisogamous or oogamous. anisogamous or oogamous. - Union of gamets takes - Union of gamets takes place in water or within the oogonium. place in water or within the oogonium.

Rhodophyceae (Red Algae) Red Pigment, r-phycoerythrin in their body Red Pigment, r-phycoerythrin in their body Found in the warmer areas Found in the warmer areas Red thalli – Multicellular Red thalli – Multicellular The food stored as floridden starch The food stored as floridden starch

PORPHYRA GRACILARIA GELIDIUM

Rhodophyceae-Reproduction Vegetative Reproduction – Fragmentation Vegetative Reproduction – Fragmentation Asexual – Non-motile spores Asexual – Non-motile spores Sexual - Non-motile gamets (oogamous) Sexual - Non-motile gamets (oogamous) e.g. Polysiphonia, porphyra etc. e.g. Polysiphonia, porphyra etc.

Algae- Economic Importance Use as Food e.g. Porphyra, Laminaria & Use as Food e.g. Porphyra, Laminaria & Sargassum. Sargassum. Certain marine brown & red algae produce large amount of hydrocolloids (water holding substances) Certain marine brown & red algae produce large amount of hydrocolloids (water holding substances) Algin – brown algae e.g. sargassum Algin – brown algae e.g. sargassum Agar used to grow microbs and preparation of icecream and jellies e.g. Gelidium & Gracilaria. Agar used to grow microbs and preparation of icecream and jellies e.g. Gelidium & Gracilaria. Rich proteins – Chlorella & Spirullina Rich proteins – Chlorella & Spirullina