Every day, somewhere on Earth, a species quietly disappears. Scientists estimate the current extinction rate is between 1,000 and 10,000 times higher than the natural background rate, which means that we are losing species at a pace the planet has not seen since an asteroid wiped out the dinosaurs. But the consequences of species extinction stretch far beyond a missing entry in a field guide. When one species disappears, it pulls on thousands of invisible threads, and what happens next can be catastrophic, irreversible, and deeply personal to every human being alive.

Here is what actually happens when a species disappears, and why the chain reaction is far more terrifying than most people realize.

The Domino Effect: How One Extinction Triggers Many More

The first and most underreported consequence of species extinction is what scientists call “co-extinction.” When a species vanishes, it rarely goes alone.

Ecosystems are not simple food chains; everything in nature depends on everything else. A single organism can be a food source, a habitat builder, a pollinator, a seed disperser, and a disease regulator all at once. When it’s gone, the species that depended on it begin to falter. Then their dependents falter. Extinction breeds extinction.