As a person who believes in the idea of survival of the fittest, I see humans at the top of the food chain; we decide which species die and which do not. Of course, as intelligent beings, we need to take into consideration our surroundings (which species are fragile, endangered, etc.), but I don't believe in the zero-sum "all or none" argument. Like I said before, dogs have been purposely domesticated from wild animals to be used as pets and companions, not food.