What triggered the Cambrian Explosion?

Abstract: The Cambrian Explosion, 540-520 million years ago marks the appearance and rise of animals on Earth. During this time we saw the rapid emergence of all major modern groups, modern-style food webs, as well as a substantial rise of animal abundance and biodiversity.  This talk will be explore the processes that may have driven this revolutionary event. Were both internal (genetic) or external (physicochemical) processes important? This radiation took place on a totally different Earth – with many continental land masses clustering around the tropics, no polar ice caps, and much lower atmospheric oxygen levels compared to today. Life had not colonised land and the modern carbon cycle was yet to form. While we are starting to understand how new forms of developmental gene regulatory networks,  pulses of oxygenation, and ecological feedbacks played key roles, unpicking the drivers of the Cambrian Explosion remain a profound puzzle in the history of life.