In Darwinian science, the predator/prey relationship is often the prototypical example of a symbiotic relationship. This is what evolution calls cooperation. Competition is when two animals need the same resource i.e. Two grazing animals who both eat the same grass. Although the predators are bad for the individual prey animal, by keeping the population down, they help insure the survival of the species.

All of which shows that my Darwinian analogy was a bad choice when applied to people. But there are kinds of ethically responsible symbiosis that we humans can participate in.