This image shows an ancient sea, from about 470 million years ago.
This is a complete ecosystem composed of abiotic (non-living) factors such as:
It also consists of biotic (living) factors such as:
Together, abiotic and biotic factors combine to form complete ecosystems, each with its own unique ecology and history.
Lets explore what fossils can tell us about past ecosystems. Well start with some abiotic examples.