The evolution of photosynthesis and its environmental impact
Photosynthesis in plants is a very complicated process, utilizing two photosystems in series to carry out the very energy-demanding process of oxidizing water to molecular oxygen and reducing carbon dioxide to organic compounds. The first photosynthetic organisms, living more than 3.4, perhaps even 3.8 Ga, i.e. American billion (109) years ago, carried out a simpler process, without oxygen product