jump to complex lf - oxygenation

 Up to 800 million years ago, the Earth’s oceans were deprived of oxygen. It was only when microorganisms called phytoplankton, capable of performing photosynthesis, colonised the oceans – covering two thirds of our planet – that production of oxygen at a massive scale was made possible. This major oxygenation event, driven by billions of tiny organisms in the ocean, set the stage for a fundamental transformation of our planet – the evolution of complex life as we know it today