The ecologist is interested in the biological organization level called an ecosystem.

Here's why:

* Ecosystem: An ecosystem encompasses all the living organisms (biotic factors) in a specific area and their interactions with the non-living components (abiotic factors) of their environment. This includes things like:

* Species interactions: Predator-prey relationships, competition, symbiosis.

* Abiotic factors: Temperature, sunlight, water availability, soil composition.

Let me know if you'd like to explore other levels of biological organization!