Ancient shark 'graveyard' uncovered in Egyptian desert - Live Science

By Ross Anderson, Associate Professor of Natural History, University of OxfordOrin Lole Durbin, PhD Student, Geosciences, Virginia Tech The question of when animals first evolved is one that has confounded scientists since the time of Charles Darwin. Studying rocks in north Wales in the mid-18th century, Darwin found the sudden first appearance of animal shells and skeletons in layers dating back over 500 million years perplexing. He had predicted a long history of evolution, with animals slowly gaining complexity through time, rather than this apparent instantaneous appearance of complex animals. The sudden appearance of complex animals has led scientists to argue that animals must have a “hidden history”, a period… Read complete article© The Conversation