Visualizing Environmental Science

Mutualism Benefits Benefits Each organism depends on the other

Organism 1 Organism 2 Characteristic of relationship

Commensalism Benefits Not affected Only one organism depends on the other

Parasitism Benefits Harmed Host harmed, rarely killed; host usually

much larger than parasite

© WILDLIFE GmbH/Alamy

Darlyne A. Murawski/NG Image Collection

© blickwinkel/Alamy

a. Categories of Symbiosis.

b. Mutualism.

Most common in

Central America,

the acacia ant

gains shelter and

nutrients from the

acacia plant, in turn

protecting the plant

from predators.

Photographed in

Costa Rica.

c. Commensalism.

Epiphytes are small plants that attach to

the branches and trunks of larger trees.

Photographed in Tanzania.

d. Parasitism.

Close-up of body

lice feeding on a

human arm. Each

louse is about

3 mm (0.12 in) long.

Interpreting Data

A bee pollinates a plant species while gathering

material to make nectar. What type of symbiosis

exists between plant and bee?

Symbiotic relationships
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