Water was present on earth at the time of the oldest rocks we can find. So were cyanobacteria. Earth’s atmosphere had to undergo some important changes, and it seems that the cyanobacteria helped this process.
Misconceptions
The Earth has always been pretty much the way it is now.
Evolution is a theory about the origin of life.
Evolution has never been observed.
The theory of evolution says that life originated, and evolution proceeds, by random chance.
Life on Earth (biosphere) has never caused major changes in the other spheres that make up the earth system, such as the rocks and air.
Read Chapter 3 in Michigan Geography and Geology
