Is extinction natural? How has the extinction rate changed over time? Why are ex

Students should discuss some of the following. Extinction is a natural process. Extinction rates have risen higher than the background extinction rate during several mass extinction events during Earth's history. In the past 440 million years, there have been five major episodes of mass extinction. If current trends continue, the modern era may see the extinction of more than half of all species. While similar in scale to previous mass extinctions, today's ongoing mass extinction is different in two respects. First, humans are causing it. Second, humans will suffer as a result.