The Great Resets: Understanding Mass Extinction Events

If a massive percentage of all living species across the planet disappear in a relatively short geological time, then the event is classified as a mass extinction.

If scientists examine the fossil record for major "gaps" where biodiversity drops significantly, then they find five distinct periods known as the "Big Five" mass extinction events.

If "background" extinction refers to the slow, natural loss of a few species over time, then a "mass" extinction must involve a much higher and faster rate of loss to be considered different.

If the extinction at the end of the Permian period was the most severe in history, then it earned the nickname "The Great Dying" among the known mass extinction events.

If a massive space rock struck the Yucatan Peninsula and caused global climate chaos, then that asteroid is the primary cause for the end of the dinosaur era.

If a disaster affects the entire planet's atmosphere or oceans, then it can cause a mass extinction; however, animals simply moving locally does not cause global mass extinction events.

If the dinosaurs disappeared roughly 66 million years ago at the boundary of the Cretaceous and Paleogene periods, then the K-Pg event is the name for that specific extinction.

If a mass extinction removes most of the predators and competitors in an environment, then the surviving species have more resources. If they have more resources and space, then they undergo "adaptive radiation" to fill those empty roles.

If older rock layers have many types of shells and bones that suddenly vanish in the newer layers above them, then the fossil record is providing physical proof of an extinction.

If the dominant species are removed by one of the mass extinction events, then the survivors no longer have to compete with them. If competition is low, then the survivors can successfully evolve into many new forms.

If an event kills over half of all species worldwide in a short time, then it is a mass extinction; however, it does not specifically require dinosaurs or be limited to the ocean.

If the Ordovician period ended with massive glaciers forming and sea levels dropping rapidly, then those cooling conditions define that specific incident among the mass extinction events.

If small animals required less food and could find shelter from the heat and soot of an asteroid impact, then they were more likely to survive than large, specialized dinosaurs.

If human activities like habitat destruction and pollution are causing species to die out at 1,000 times the normal rate, then many biologists categorize this as a "Sixth" mass extinction.

If trilobites and ancient corals vanished at the end of the Permian, then they were victims of that event; however, humans and flowering plants did not exist yet during the Permian mass extinction events.

If species have millions of years to adjust to a change, they can evolve. If the change happens in a few thousand years, then most species cannot keep up and will die, which creates a mass extinction.

If the Tree of Life represents the history of all species, then an extinction kills off entire groups forever. If those groups are gone, then those branches on the tree are "pruned" or stopped.

If the normal rate of species loss is the "background" rate, then the large, sudden losses are the "mass" events that stand out in history.

If the Permian extinction was caused by global warming and acid rain from CO2, then a source of gas was needed. If millions of years of lava flow erupted in Siberia, then those volcanoes provided the gas for that extinction.

If iridium is rare on Earth's surface but common in asteroids, and if a layer of it appears globally at the same time the dinosaurs died, then it proves a space impact occurred.