This timeline of the evolution of life outlines the major events in the development of life on the planet Earth. For context, see geologic time scale, and the history of Earth. Dates given are estimates based on scientific evidence. The table uses the symbols "Ma" for "mega-annum (million years ago)" and "ka" for "kilo-annum (thousand years ago)". English literature also uses the abbreviations "mya" (m.y.a) and "tya" (t.y.a) or "kya" in the same sense. The basic timeline is a 4600 million year old Earth, with For a list of our common ancestors with other living species, see The Ancestor's Tale.