well for a start 70 % of the earth's surface cover by ocean.let's put that into context.what that means is that we could put all of the land into the pacific ocean and still have room left over for nearly two more Australians.As we'll see later in this module,life is self evolved in the ocean.This happened about 3.9 billion year ago when there was no free oxygen in the atmosphere and the early cells obtained their carbon.which is an element essential to all life from carbon dioxide and their energy from inorganic material.cyanobacteria are relatively simple single celled organisms that