How bad was Earth’s first major extinction?

A deeper, deadlier wipeout in Earth’s deep past

New fossil discoveries have rewritten how dramatic life’s first major die-off was about 550 million years ago. Paleontologists studying beds that preserve soft-bodied organisms found that a much larger fraction of Ediacaran-era life disappeared than previously estimated—nearly four out of five species vanished. Many of those lost creatures were large, sessile invertebrates with frond-like bodies that anchored to the seafloor and filtered nutrients from seawater.

That scale of loss matters because it cleared ecological space at a formative time in animal evolution. The disappearance of abundant, ecologically important organisms would have reshaped food webs, nutrient cycles and habitat structure, directly influencing which lineages survived and how rapidly new forms appeared afterward. In short, the event didn’t just trim biodiversity; it rewired early marine ecosystems at a crucial juncture when animals were diversifying.

What the fossils tell us

• The mortality affected a broad swath of the soft-bodied community, not just a few rare taxa.
• Many of the victims occupied roles as dominant, space‑holding seafloor organisms.
• The timing—about half a billion years ago—falls just before bursts of animal diversification that populate later rock layers.

Why scientists care

Understanding the magnitude and selectivity of this early extinction helps researchers test hypotheses about drivers and consequences. Did environmental shifts, changes in ocean chemistry, or biological interactions drive the collapse? Evidence so far points to a sudden reordering rather than a slow fade, but the immediate causes remain uncertain. The finding strengthens the idea that mass extinctions can act as evolutionary reset buttons: by erasing dominant forms they open ecological opportunities that shape the trajectory of life for millions of years.