* Ecosystem: A specific area where living organisms (biotic factors) interact with non-living components (abiotic factors) of the environment. Examples include a forest, a lake, a coral reef.

* Biosphere: The sum of all ecosystems on Earth. It encompasses all living things and their environments, from the deepest oceans to the highest mountains.

Think of it like this:

* Ecosystem: A single room in a house.

* Biosphere: The entire house, including all the rooms and the surrounding land.