Basics of Biology

Biology and Life

What was the Cambrian Explosion?

The Cambrian Explosion occurred, logically, at the beginning of the Cambrian period, about 544 million years ago (on the geologic time scale, it also marked the end of the Precambrian era and the beginning of the Paleozoic era). At this time, a huge explosion of life occurred in the oceans—most of them similar to modern marine animal groups— with a rapid diversification between the different groups. It took about another one hundred million years—around 440 million years ago—before the first animals crawled on land and a second burst of animal growth occurred.


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