Permian Extinction

In some beds, trilobites lie stacked and oriented in the same direction, suggesting they were overwhelmed at once rather than scattered over years. Geochemists find signs of anoxia and other stress in the surrounding rock, linking these death horizons to broader environmental crises that built toward the end Permian extinction. In a single slab, it is possible to see both a local event and a chapter in a much larger planetary disruption. The mass death beds show that extinction is not always gradual. Sometimes, entire communities can be wiped out in a single catastrophic event, leaving behind a record of the moment when the world changed.

After trilobites vanished, their ecological spaces were eventually filled by other invertebrates that radiated into a world with different chemistry, climates, and food webs. Extinction turned one style of life into a memory and cleared room for new evolutionary experiments. In the Tree of Life, trilobites are not a side note but a long branch ending at a sharp cutoff that reshaped everything that came after. The extinction shows that death can create space for new life. The disappearance of trilobites opened ecological niches that were filled by new forms, demonstrating that extinction is part of the ongoing process of evolution.