How did oxygen become such a major component of the current atmosphere?
The first single cell organisms used photosynthesis for energy, and oxygen, one of the byproducts of photosynthesis, was released into the atmosphere in abundance.
Oxygen has always been around in our atmosphere, however, since it reacts so readily, it started out as mostly carbon dioxide,
It turns out that photosynthesis does exactly that. During photosynthesis,
Looking at the chemical equation above, we can see that carbon atoms are pulled off the
Before there were animals, however, the
During the Archaean Era, about 3.5 billion years ago, the first single celled organisms began photosynthesizing. These cyanobacteria pumped out tons of oxygen into the atmosphere.