Predation: Stretching the Bounds of Symbiosis
We are all aware that many organisms must eat other organisms in order to survive. This is just a fact of nature. And it should be rather obvious that one of the species benefits from predation (the predator) and one is negatively impacted (the prey).
If we look at symbiosis in its most general terms, as the interaction of two different species of biological organisms, it is easy to see that predation falls under the category of a symbiotic relationship.
But there is much debate about what interactions fall under the heading of symbiosis. The most narrow interpretation claims that only persistent mutualism should be referred to as symbiosis. Others add to this two other persistent interactions: Commensalism and parasitism. And still, others maintain a looser definition, adding other associations such as competition and predation as well as others.
In my short time discovering the amazing ways in which organisms interact, I have come to personally settle on the middle ground. I look at symbiosis as the interplay of organisms while they live (with few exceptions). When a great white shark gobbles down a sea lion, there has been an interaction between the two. They have both been affected by this interaction. One’s life ends, and the other has gained vital nutrients it requires, and has earned the right to live on – until it must hunt again. But there has not really been a longstanding association between these specific individuals.
We have a tendency to see the hunter as the villain and the potential prey as a victim. It is an understandable reaction. Every time I watch a nature show and a carnivore is in hot pursuit of a possible meal, I am on the edge of my seat, hoping the poor thing is able to outdistance or outmaneuver its pursuer. But we must remember that the predator is only using the tools that evolution has dealt it, in order to survive.
Some predators succumb to hunger, while others learn to become successful hunters. Many individuals escape predation. Others do not. Survivors on both sides are able to breed. In some instances, they are able to pass on some small advantage to their offspring. Over time, genetic traits in both predator and prey species are strengthened.
Considering the interaction of predator and prey from an evolutionary viewpoint, it is possible to see that there could be a certain amount of benefit derived from both species. So, from a certain perspective, you could even make the case that there is a small mutualistic component to their relationship.
I am not suggesting that the predator/prey relationship should now be re-categorized as mutualistic. I am just saying, just as there are often negative elements to a mutualistic relationship, there can also be positive aspects to less favorable affiliations – even predation.