Thousands of Algal species are found in this world. They have diversity in shape, size and structure, but all of them contain different photosynthetic pigments and thus they are autotrophic.
A short description of Spirogyra, as a. representative of algae, is stated there.
Structure : They are green, un-branchedfilamentous algae. Their chloroplasts are band shaped, spirally arranged in the cell. The name- Spirogyracomes from this spiral chloroplast.
There are pyrenoids in the chloroplasts. The vegetative cell's are elongated and each cell contains a well-organised nucleus and a large vacuole. Their body is slippery and the cell wall is three layered.
Sexual reproduction occurs by the process of conjugation. They also reproduce by fragmentations (Filament break up into short pieces and each part grown into a new filament) or by spore formation.
It is an important source of fish- food. It may .also be used for human food by special processing. It plays a great role in the natural food cycle.