approximately when did the ancestor of all life on earth live
Last universal common ancestor The last universal common ancestor (LUCA), also called the last universal ancestor (LUA), cenancestor, or (incorrectly[R 1]) progenote, is the most recent population of organisms from which all organisms now living on Earth have a common descent.[1] LUCA is the most recent common ancestor of all current life on Earth. LUCA should not be assumed to be the first living organism on Earth. The LUCA is estimated to have lived some 3.5 to 3.8 billion years ago (sometime in the Paleoarchean era).[2][3] The composition of the LUCA is not directly accessible as a fossil, but can be studied by comparing the genomes of its descendents, organisms living today. By this means, a 2016 study identified a set of 355 genes inferred to have been present in the LUCA.[4]