# Cambrian explosion

> English word · Proper noun · IPA /ˈkam.bɹɪ.ən ɪkˈspləʊ.ʒən/

## Definitions
1. The relatively rapid appearance, during the Cambrian Period around 541 million years ago, of most major animal phyla, as demonstrated in the fossil record.

## Etymology
Of unclear origin, inspired by George Gaylord Simpson's description of "explosive" evolution. The earliest known use is in a BSCS high school biology textbook written in 1961 under the direction of paleobotanist Wilson Steward.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/cambrian-explosion