San'okunen mae Koseidai Sekitanki no Chikyū ni wareware no senzo wa arawareta Jinrui no rekishi o nihyakugojū-mannen to sureba Sono zatto hyakunijūbai no mukashi daOur ancestors emerged on this Earth 300 million years ago, in the Paleozoic Carboniferous. Given that human history has only spanned 2.5 million years, our species is about 120 times older.