Trilobite fossils - resources and class activities

These activities use trilobites as a case study in evolution, connecting how fossils form with other topics in the primary science curriculum. See Evolution across primary science for why this is important.

Trilobite introduction

Trilobites, together with ammonites, are some of the most iconic small fossils. They were once very common marine creatures. Palaeontologists recognise more than 4,000 genera, grouped into more than 150 families.

Trilobites lived in all Earth’s oceans for hundreds of millions of years. They had tough exoskeletons, which made them more likely to fossilise. The detailed fossil record of trilobites shows how species gradually evolved, changing form as they adapted to changing environments.

They are found in the fossil records from 521 to 252 million years ago. Despite their success over such a long time, the fossil record indicates that their numbers and diversity declined steadily over 100 million years. Palaeontologists are still working out what led to this decline, but it’s likely a combination of increasing predator diversity and environmental change.

Finally, 252 million years ago, at the end of the Permian Period, massive environmental changes pushed the trilobites to extinction, along with more than 90% of other marine species.

General trilobite resources

Trilobite activities

Related pages