Question

What are Cyanobacteria and what is its role in microbial evolution?

Answer 1

Cyanobacteria or blue green algae (they are relative to bacteria not algae. This algae term came as they are aquatic and make their own food) are only photosynthetic bacteria. They are considered as oldest foosil about 3.5 bilion years ago.Cyanobacteria were then only photosynthetic bacteria that can produce oxygen. Thus cyanobacteria released oxygen in environment during archean and proterozoic era and various life originated since then. Before that harsh atmosphere of earth made it unable to live. During late proterozoic and early cambrian era endosymbiosis of cyanobacteria with eukaryotic cell lead to generation of chloroplast : gives food to eukaryotic cell in return of a safe home. This endosymbiosis is the key of plant origin.