Cyanobacteria

The world’s oldest living organisms? Only heard about these critters last week, they first appeared around 3.5 billion years ago when our atmosphere was pretty murky and not really suited to life as we know it.

These guys changed all that with their abilities in photosynthesis they started pumping Oxygen into the seas of that time. Initially the Oxygen combined with the Iron in the water generating considerable Iron Oxide deposits - pretty handy considering the large number of ways that we find Iron to be useful.

After all the Iron had gone from the seas there was nowhere else for the Oxygen to go except into the atmosphere - which from this point on gave us the starting place for all the life on earth that followed.

They are still around today so let’s here it for these plucky fellows without whose help the rest of us would not be here.

As a by product they left behind a fossil record of Stromatolites which are described and shown over here.