The end-Guadalupian extinction event around 259.8 million years ago is considered one of the major mass extinctions in Earth's history, alongside five others. This event caused a significant loss of species diversity, similar to the more well-known mass extinctions like the one that wiped out the dinosaurs. In fact, there may have been a total of six major mass extinctions in Earth's history, not just five. This suggests that the current decline in species diversity could be considered the seventh major extinction event.