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:

• the sea level
• the sand, and
• the temperature of the water

It also consists of biotic (living) factors such as:

• the plants and animals, and
• their interactions.

Together, abiotic and biotic factors combine to form complete ecosystems, each with its own unique ecology and history.

Let’s explore what fossils can tell us about past ecosystems. We’ll start with some abiotic examples.