Paleoproterozoic

The Paleoproterozoic ( /ˌpeɪlɪ.oʊˌproʊtərɵˈzoʊ.ɨk/; also Palaeoproterozoic) is the first of the three sub-divisions (eras) of the Proterozoic occurring between 2,500 to 1,600 million years ago. This is when the continents first stabilized. This is also when cyanobacteria evolved, a type of bacteria which uses the biochemical process of photosynthesis to produce energy and oxygen.