Question

The classification of algae is based upon

• A. Nature of sex organs
• B. Nature of their pigments
• C. Nature of their spores
• D. All of the above

Answer 1

The correct option is B Nature of their pigments

The classification of algae is based upon the pigments present in them.

• Class (1) Chlorophycrae (green algae): Pigments are present in plastids or chromatophores. Pigments are chlorophyll, xanthophylls and carotene. Starch is photosynthetic food product, but rarely oil as in vaucheria. In chromatophores pyrenoids are present. Both flagella are equal in length i.e. they are isokonate. Majority of genera live in fresh water and few live in marine water. Cell wall is of cellulose e.g. chlamydononas, char, vaucheria, volvox, cladophora, stigiocloxeum, ulothrix and chlorena.
• Class (2) Rhodophyceae: They are called red algae chrometophores possess red pigment. Reserve food material is Polysaccharides starch and soluble sugar. They are non motile i.e. flagella re absent. Mostly marine and few are fresh water. Sexual reproduction is speciality and advanced e.g. Polysiphonia, Batrochospermum.
• Class (3) Pharophycrae: They are called brown algae. Plants seem to be yellow brown in colour. Chromatophores are yellow brown in colour. Reserve food products are alcohols, mannitol and Lamixarine. Motile reproductive cells are pyriform with tow laterally inserted flagella. Always multicellular plant body is present. They are mostly marine and rarely fresh water. Zygote has no resting period. E.g. Fucus, Ectocarpus.
• Class (4) Myxophyceae: They are blue green algae. There are mostly fresh water and few marine. Pigments are present in peripheral portion of protoplast. Plants are blue green due to pigment C-phycocyanin. Reserve food products are sugars and glycogen like compounds cells cynophecean starch. Flagella are absent sexual reproduction is unknown. Mynophyceae is also called cyanophyceae or schizophyceae e.g. oscillatoria, Nostoc.
• Class (5) Chrysophyceae: They are called brown or orange Algae. Phycocheysin is dominant pigment which gives brown or orange colour to Algae plants. Chronatophore has naked pyrenoid bodies. Food reserve is chrysolaninarim and lencosin. Cell wall is cilified or calcified with no cellulose. There are two equal or unequal flagella. Sexual reproduction is rare, if present it is isogamous e.g. chrysallonium, chrysococcus, chrysopsphaera.