Prepared by : Km. Monika Balmiki KV GANGTOK

1. ALGAE Prepared by : Km. Monika Balmiki KV GANGTOK

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

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

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

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

6. Isogamous Anisogamous Oogamous

7. CLASSES OF ALGAE • The Algae are divided into three mail Classes: • Chlorophyceae • Phaeophyceae • Rhodophyceae

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

9. CHLAMYDOMONAS VOLVOX ULVA

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

11. Phaeophyceae(Brown Algae) • Marine habitats • 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. • Accumulation of reserve food as fats and oil rather then starch. • The cellulosic wall covered by algin • Centrally located vacuole and nucleus.

12. LAMINARIA DICTYOTA SARGASSUM

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

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

15. GRACILARIA PORPHYRA GELIDIUM

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

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

18. THANK YOU