Photosynthesis More recent studies, reported in March 2018, also suggest that photosynthesis may have begun about 3.4 billion years ago. The main source of oxygen in the Earth's atmosphere derives from oxygenic photosynthesis, and its first appearance is sometimes referred to as the oxygen catastrophe. Geological evidence suggests that oxygenic photosynthesis, such as that in cyanobacteria, became important during the Paleoproterozoic era around 2 billion years ago. Modern photosynthesis in plants and most photosynthetic prokaryotes is oxygenic. Oxygenic photosynthesis uses water as an electron donor, which is oxidized to molecular oxygen () in the photosynthetic reaction center. Several groups of animals
What Do You Care What Other People Think? What Do You Care What Other People Think? "What Do You Care What Other People Think?": Further Adventures of a Curious Character (1988) is the second of two books consisting of transcribed and edited, oral reminiscences from American physicist Richard Feynman. It follows "Surely You're Joking, Mr. Feynman!". Richard Feynman received the Nobel Prize in Physics in 1965 for his contributions to the development of quantum electrodynamics. He is a theoretical physicist known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, and the physics of the superfluidity of supercooled liquid helium, as