What defines an endemic species?

• A. Species found only in a defined geographic area.
• B. Species found worldwide.
• C. Species that migrate seasonally.
• D. Species introduced by humans.

Answer: (A)

Endemic species are those found only in a defined geographic area and nowhere else. This restricted distribution often results from long-term isolation or very specific habitat needs, so the species persists only within that particular region. Because their entire population relies on that limited area, they’re especially vulnerable to changes like habitat loss, climate shifts, or invasive species, which is why endemics frequently become conservation priorities.

In contrast, a species found worldwide is described as cosmopolitan, not endemic. Migration describes movement patterns rather than geographic restriction, so a migratory species can span large areas even if it periodically returns to particular places. Being introduced by humans refers to how a species arrived in a location, not whether its natural range is limited, so that criterion doesn’t define endemism.