<P> The last universal common ancestor ( LUCA ) , also called the last universal ancestor ( LUA ) , cenancestor , or ( incorrectly ) progenote , is the most recent population of organisms from which all organisms now living on Earth have a common descent . 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 ) . 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 . </P>
<P> The last universal common ancestor ( LUCA ) , also called the last universal ancestor ( LUA ) , cenancestor , or ( incorrectly ) progenote , is the most recent population of organisms from which all organisms now living on Earth have a common descent . 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 ) . 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 . </P>
approximately when did the ancestor of all life on earth live
approximately when did the ancestor of all life on earth live
3.5 to 3.8 billion years ago ( sometime in the Paleoarchean era )
3.5 to 3.8 billion years ago ( sometime in the Paleoarchean era )