Not "all" hybrids in the wild are selected against. some dont thrive, and die. some, seveal generation, hybs become sterile. some are successful and go on to improve the new breed and/or species. nature decides what will be successful. its true that hybrids play a much smaller role in natural selection than mutation, but there is alot more hybridization going on out there, than in captivity. humans play a small roll in this, and some are careful about it getting out of hand, and some are not. thats a natural balance of sorts. the human is in fact a product of natural selection, and any thing he does is natural, incuding hybridizing other species. what if an other form, evolved higher inteligents before humans, and decided not to let primates hybridize or mutate, and killed off those products. well there wouldnt be any humans to mess up every thing else. if we nuke the planet or make it too poison to live on, well then the planet will change again, and on, and on. some of us dont want this to happen, and are trying to change the world for the better. and some just dont care what happens after they are gone. nature will make the final decision. its going to happen whether you like it or not. some folks like hybrids, and some dont. its not worth stressing, and getting high blood presure about. live and let live.
