PARASITSM - Is a relationship between two things in which one of them (the parasite) benefits from or lives off of the other. For example a leech and a catfish the leech is benefited because it sucks the catfishes blood.
MUTUALISM- When both organisms are effected in a good way one example of this is algae and fungi the algae and fungi work together to make communities called lichens. The algae creates oxygen for the fungi and the fungi makes food for the algae. This is an example of mutualism because both organisms are helped.
COMMENSALISM- One organism gains from the relationship and the other organism does not. An example of this is pond weed and fish. This is an example of commensalism because the pond weed provides shelter for the fish but the fish do not harm the pond weed or help it.
PREDATOR PREY RELATIONSHIP-When a predator feeds on is prey. An example of this is a alligator eating a fish. This is predator prey relationship because the predator (the alligator) eats the prey (fish).
Competition -the activity or condition of competing. An example of competition is ten alligators competing over five fish.