
Around 550 million years ago (the Cambrian period), a revolution happened. Our distant, soft-bodied ancestors evolved teeth, claws, graspers, hooks, spines and all manner of other weapons. This was evolution of the predators. As a consequence, life went through an explosion of variety. In the Cambrian sea, every creature stalked, shuffled and swam through the sunlit waters. No sooner did thick armour evolve for defence, but creatures like the mighty Anomalocaris evolved a round, crushing mouth to destroy it. In this sea, the segmented Tuzoia gave rise to all crabs and insects, the round Arkarua became ancestor of starfish and sea urchins, and the small harmless Pikaia became ancestor to everything with a backbone, from the Great White shark to the dinosaurs.
