Question

Why can it be said that Cyanobacteria prepared Earth for the evolution of higher life forms?

Answer 1

In primitive earth reductive environmental conditions are prevailed and as such oxygen is not available. It was assume that cyanobacteria evolved at 3.5 billion year ago and they survived in reductive environment at protozoix Eras. They developed the photochromatic system and use it to obtain the energy from the sun and slowly concentration of oxygen is increased in atmosphere. Some cyanobacteria become the integral part of plants and photsnthetic system of thyalkoid and blue green algae is developed by the cyanobacteria. There are several evidences such as presence of membrane, self DNA, 16s smimilarity with cyanobacteria of chroloplas indicate that they are the part of cyanobacteria. On the basis of these arguments one can say that primitive environment is changed by the cyanobacteria.