SCIENCE 4

Interaction Between

Living Things

An ecosystem is a community of interacting organisms and their environment.

Living things (biotic factors) interact with each other.

With non-living things (abiotic factors) like soil, water and air.

Beneficial Interactions Mutualism - occurs when both organisms benefit from an

interaction. Examples: ox pecker—zebra, bee—flower, sea anemone—clownfish

Beneficial Interactions Commensalism—One organism benefits from an

interaction, but the other gets nothing. Examples: remoras—shark, Orchids—trees

Harmful Interactions Parasitism—one organism, the parasite, is benefited and

the other organism called the host is harmed. Examples: Dog—ticks, mosquito—human

Harmful Interactions Predation—This is an interaction in which one organism,

called the predator, hunts and eats another organism called the prey.

Examples: Tiger—deer, bear—fish

Harmful Interactions Competition—Type of interaction where two or more

organisms compete with each other for things like food and shelter. One or both organisms may be harmed.