The Cambrian explosion is one of the most significant events in Earth’s 4.5-billion-year history. The surge of evolution led to the sudden appearance of almost all modern animal groups. Fossils from the Cambrian explosion document the rapid evolution of life on Earth, but its cause has been a mystery.
The sudden burst of new life is also called “Darwin’s dilemma” because it appears to contradict Charles Darwin’s hypothesis of gradual evolution by natural selection.
“At the boundary between the Precambrian and Cambrian periods, something big happened tectonically that triggered the spreading of shallow ocean water across the continents, which is clearly tied in time and space to the sudden explosion of multicellular, hard-shelled life on the planet,” said Dalziel, a research professor at the Institute for Geophysics and a professor in the Department of Geological Sciences.
The article on Phys.org: Massive geographic change may have triggered explosion of animal life.
The original research abstract Geology, October 2014, v. 42, no. 10: Cambrian transgression and radiation linked to an Iapetus-Pacific oceanic connection? This may be available to you via your local library. My library provides online (from home!) access to many scientific journals and search services, but none of them had this article yet.