About algae by Badshah Javed

                           ALGAE.

The branch of botany which deals with the study of algae is called "phycology" (phycos =sea,logos =discourse ).

Algae are chlorophyll bearing, simple, thalloid, auto trophic and largely aquatic organisms.
They generally found in fresh water as well as marine water, on trees, stones, mud or soil and all types of water reservoirs. The algae may be terrestrial or aquatic.

                  FRESH WATER ALGAE.

Oedogonium, Chara, Chlamydomonas and volvox etc.which are found in fresh water and called fresh water algae.

                    MARINE WATER ALGAE.

Ectocarpus, Sargassum and polysyphonia etc. Which are found in marine water and called marine water algae.
     
                    TYPES OF ALGAE .

The algae are divided into three major classes : Chlorophyceae, Phaeophyceae and Rhodophyceae.

                     CHLOROPHYCEAE.

The members of Chlorophyceae are commonly called as green algae. They generally found in fresh water. The Chlorophycean algae contains Chlorophyll a and b, carotenoids -xanthophylls and carotenes which are localised in definite chloroplasts. The chloroplasts may be discoid, plate-like, reticulate, cup-shaped, ribbon shaped  in different species. Most of the members have one or more storage bodies which are called pyrenoids and located in the chloroplasts. Pyrenoids contain protein besides starch. The Chlorophycean algae have a rigid cell wall which is made of an inner layer of cellulose and an outer layer of pectose. Some commonly found green algae are : Chlamydomonas, Volvox, Ulothrix, Spirogyra and chara.

                      PHAEOPHYCEAE.

The members of Phaeophyceae are commonly called as brown algae.They primarily found in marine habitats.The Phaeophyceaen alge contains fucoxanthin named pigment  which are responsible for Its brownish colour. The food is stored as complex carbohydrates, which may be in the form of laminarin or mannitol.The vegetative cells have a cellulosic wall which are usually covered on the outside by a gelatinous coat of algin.The plant body is usually attached to the substratum by a holdfast,and has a stalk, the stipe and leaf like photosynthetic organ -the frond.

                      RHODOPHYCEAE.

The members of Rhodophyceae are commonly called as red algae. Why they are called as red algae? Because of the predominance of the red colour pigment, r-phycoerythrin which is present in their body. The red algae primarily found in marine habitats which may be surface of water and also in a great depths of oceans where relatively little light penetrates. The red thalli of most of the red algae are multicellular. Some of them
have complex body organisation. The food is stored as floridean starch which is very similar to amylopectin and glycogen in structure.