Picture a primordial Earth: a world of muted browns, greys and greens. Fast forward to today, and Earth teems with a ...

These familiar marine arthropods first arose about 545 million years ago in the early Cambrian and thrived throughout the world's oceans until they were wiped out in the Permian extinctions about ...

These terrestrial pioneers were arthropods, such as primitive centipedes and arachnids, the ancestors of spiders. The first true plants began to take root on land some 430 million years ago.