1. Symbiosis: It describes a close relationship between two organisms from different species. It is sometimes, but not always, beneficial to both parties.
2. Mutualism: A relationship between two species of organisms in which both benefit from the association.
3. Commensalism: A type of relationship where one of the organisms benefits greatly from the symbiosis. The other is not helped, but is not harmed of damaged from the relationship.
4. Parasitism: In parasitism, one organism benefits from the relationship but at the expense of the other. The organism may live inside the other’s body or on its surface. In some of these parasitic relationships the host dies and in others, it is important that the host remain alive.
Sea anemones and hermit crabs. The sea anemone gives protection to the crab using its stinging cells, and it remolds its shell to fit the crab while the hermit crab allows the sea anemones to consume the remains of its food, providing it with food supply. In this case, both the sea anemones and hermit crab benefit as the they either are getting protection or food remains.
Another example is that of the oxpecker (a kind of bird) and a rhinoceros or zebra. Oxpeckers land on rhinos or zebras and eat ticks and other parasites that live on their skin. The oxpeckers get food and the rhinoceros or zebra get pest control. Also, when there is danger, the oxpeckers fly upward and scream a warning, which helps the rhinoceros or zebra.