The Greatest Animal War
Competition in Cambrian seas helped cause an explosion in diversity
By Brooke Borel
Battles fought 542 million years before today helped fuel a blast that brought humans and most animals into existence. The great Cambrian Explosion was a period of unprecedented one-upmanship. Beastly claws crushed through thin skin, and soft-bodied creatures evolved shells shaped like scythes, sickles, and shields.
For about a billion years prior, the cells and genes that would later create animals were…