Two or more species that engage in mutually beneficial interactions.

A species that does not belong in a balanced ecosystem, comes in, and changes it (usually for the worse).

A species that helps to manage prey populations, which in turn controls the ecosystem's producers (vegetation).

A species whose value is tied to its large geographic range, and sometimes includes migratory organisms.

A species that becomes popular in media, drawing attention to its fragile or endangered habitat.

A species that creates and/or maintains a habitat, often the basis for an entire ecosystem.

A species whose behavior contributes to the physical geography of their habitat, making or modifying habitat.

A species that is very sensitive to environmental changes and can help humans identify if the habitat is suffering.

A species whose consumption of plants helps control the physical and biological aspects of an ecosystem.