Toxic Cambrian oceans

摘要

By 520 million years ago, the oceans of the world were teeming with diverse forms of animal life addicted to the newly abundant, life-giving oxygen in the surface environment. Arthropods, many - like the trilobites - now extinct, ruled the seas, over-shadowing the relatively few extant members of our own animal group, the chordates. But the course of this 'Cambrian explosion' of life did not run smoothly, and on page 80 of this issue Gill et al. illuminate a likely cause.