Symbiosis

interaction between two different organisms close together

Mutualism

Beneficial for both organisms involved.

Example: a fish eating bacteria off of a shark

Parasitism

A relationship between two things in which one of them benefits from or lives off of the other.

Example: a dog and a flea

Commensalism

An association between two organisms in which one benefits and the other derives neither benefit nor harm.

Example: A whale and barnacles