MARK OF LIFE IN EARTH

          Above 5 billion years ago our earth is occupied by giant rocks and endless sea water with the combination of chemicals and organic compounds..our ancient landscapes has same boundaries called as "PANGEA"..Where all the continents are grouped together..

          4.5 Billion years ago :We know that the ocean were full of organic compounds when lighting strikes the sea process takes place..The compounds get combined with other related compounds to form a complete chain..Which is similar to "electrolysis" process..Thus reaction takes place all over the sea..There life begins in the form of singled cell object called "Cyanobacteria"...Hence bacteria's are the first to occupied our earth.

    ROLE OF CYANOBACTERIA(4 billion years ago): The major work done by cyano is "PHOTOSYNTHESIS"..It takes the energy from the Sun and converts the carbon dioxide (co2) to oxygen (o)..Thus it is birth of oxygen in earth..The process is done by millions and millions of cyano's under sea..Thus oxygen spread all over to the atmosphere from the sea..

          CONCLUSION : Hence the first thing in earth were bacteria's which involving to produce oxygen for us..after years passes plants replace cyano's to do that..