From an evolutionist standpoint, it's basically required. In the grand scale of the universe there would have to be.
From a Christian standpoint, only non-sapient life could exist (Eve being the mother of all "living" [sapient, for a modern translation], and the chances of that existing are slim.
From a religious standpoint, why are you questioning the pope/allah/buddah/zeus/jupiter/spaghetti monster/god-emperor/primus you heretic