Cambrian Period
541-485 million years ago
About this Period
Explosion of complex life forms
The Cambrian period marked a profound change in life on Earth known as the "Cambrian Explosion"—one of the most significant events in the history of life.
During this remarkable time, nearly all modern phyla of animals appeared in the fossil record over a relatively short geological timespan. Complex organisms evolved mineralized shells, exoskeletons, eyes, and other sophisticated features that dramatically improved their survival and preservation as fossils.
Notable creatures of this period include trilobites (dominant arthropods with compound eyes), Anomalocaris (an apex predator up to 1 meter long), and bizarre forms like Hallucigenia and five-eyed Opabinia. The first chordates—ancestors of all vertebrates including humans—also appeared during this time.
The Cambrian Explosion transformed Earth's oceans from a world of simple organisms to one teeming with complex, diverse animal life.
