This Is the Way the Animals Arose: Not With a Bang, but With a Bunch of Bangs

If you were to condense the planet’s 4.5-billion-year history into a single calendar year, then sometime from the 18th to the 20th of November, as conventional wisdom would have it, the animal kingdom would undergo a dramatic transformation. A world dominated by blobby, sedate creatures that sift seawater for food would suddenly give way to a new menagerie of active predators and prey, sporting innovations such as eyes, jaws, legs, and shells. The ancestors of all the major modern animal groups would appear, and seemingly take over from their predecessors.

This 20-million-year period is known as the , and few events in the history of the Earth have been so,” “,” and “.’” But a team of researchers led by at the University of Edinburgh think the famed event wasn’t all that singular.