| Description | Interaction | Example |
| One species benefits by feeding off dead organisms in another species | |
| Two species compete for resources, usually resulting in survival of the fittest. | |
| One species benefits and the other species is not affected | |
| One species suffers and the other species is not affected | |
| Both species benefit | |
| One species benefits at the other's expense but both species remain alive. | |
| One species benefits by killing the other species | |