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
Do What You Gotta Do Do What You Gotta Do "Do What You Gotta Do" is a song written by guitarist Pat Flynn and recorded by the New Grass Revival for their 1989 Capitol album "Friday Night in America". The song was also recorded by American country music artist Garth Brooks. It was released in January 2000 as fifth and final single from the 1997 album, "Sevens". The song reached number 13 on the U.S. "Billboard" Hot Country Singles & Tracks (now Hot Country Songs) charts and peaked at number 18 on the Canadian "RPM" Country Tracks chart. The song was issued over two years