Top 10 facts about Algae! NEET | NTA NEET | NEET UG EXAM | BioLogical

 NEET | NTA NEET | NEET UG EXAM | BioLogical

• Algae are chlorophyll-bearing, simple, thalloid, autotrophic and largely aquatic (both fresh water and marine) organisms. 

• The form and size of algae is highly variable, ranging from colonial forms like Volvox and the filamentous forms like Ulothrix and Spirogyra.

• The algae reproduce by vegetative, asexual and sexual methods.Vegetative reproduction is by fragmentation. Each fragment develops into a thallus. 

• Asexual reproduction is by the production of different types of spores, the most common being the zoospores.  

• These gametes can be flagellated and similar in size (as in Ulothrix) or non-flagellated (non-motile) but similar in size (as in Spirogyra). Such reproduction is called isogamous. 

• Fusion of two gametes dissimilar in size, as in species of Eudorina is termed as anisogamous. 

• Algae are useful to man in a variety of ways. At least a half of the total carbon dioxide fixation on earth is carried out by algae through photosynthesis. Being photosynthetic they increase the level of dissolved oxygen in their immediate environment. 

• Many species of Porphyra, Laminaria and Sargassum are among the 70 species of marine algae used as food. Certain marine brown and red algae produce large amounts of hydrocolloids (water holding substances), e.g., algin (brown algae) and carrageen (red algae) which are used commercially. 

• Agar, one of the commercial products obtained from Gelidium and Gracilaria are used to grow microbes and in preparations of ice-creams and jellies. Chlorella a unicellular alga rich in proteins is used as food supplement even by space travellers. The algae are divided into three main classes: Chlorophyceae, Phaeophyceae and Rhodophyceae.