What Does It Mean When a Type of Algae Grows on a Sloth?

Commensal Relationship: Algae and Sloth

When a type of algae grows on a sloth, it raises the question of what kind of relationship exists between the two organisms. In biology, symbiotic relationships between different species are common, and one of these relationships is called commensalism.

Commensalism occurs when one organism benefits while the other is neither benefitted nor harmed. In the case of algae growing on a sloth, the algae benefit from having a habitat to grow on, while the sloth is not affected positively or negatively by the presence of the algae.

For the algae and the sloth to have a commensal relationship, it must be true that:

What Must Be True?

a. The sloth must be helped by the algae in some way.

b. Neither the algae nor the sloth can benefit from the relationship.

c. The sloth can neither be harmed nor helped by the algae.

d. The algae must be harming the sloth in some way.