Cambrian explosion

American  

noun

1. the rapid appearance during the Cambrian Period of a large number of multicelled life forms which are the ancestors of almost all modern animal phyla.

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Cambrian Explosion Scientific  

1. The rapid diversification of multicellular animal life that took place around the beginning of the Cambrian Period. It resulted in the appearance of almost all modern animal phyla.

2. See Note at Burgess Shale

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Example Sentences

For years, scientists believed that the rapid rise of diverse and complex animals, known as the Cambrian explosion, began around 535 million years ago.

From Science Daily • Apr. 6, 2026

Han said his team was also surprised that some of the animals in the quarry had also been found at Canada's Burgess Shale site, which dates from an early period of the Cambrian explosion.

From Barron's • Jan. 28, 2026

By the beginning of the Cambrian explosion of multicellular organisms about 540 million years ago, the ancestors of today’s ecdysozoans were already alive and varied in form and behavior, suggesting they arose even earlier.

From Science Magazine • Nov. 20, 2024

Think of it as the sequel to the more famous, earlier Cambrian explosion, which saw the rapid origin of many different kinds of animal bodies and groups of living things in the seas.

From Slate • Oct. 21, 2024

Before the Cambrian explosion species seem to have succeeded one another rather slowly.

From "Cosmos" by Carl Sagan