The AI we have today (which is weak AI) is already impacting our world. It influences many important segments of our society, including the stock market, medicine, internet (in general), games, etc. From an evolutionary perspective, if full AI is developed, it's highly probable that such AI will dominate us, just as we dominate all beings that are above us. The way I look at it, it's our arrogance that will eventually kill us, for we often like to believe that we are the best this universe has to offer.