How do mass extinctions differ from background extinctions?

Question

Quizplus · Accepted Answer

Mass extinctions involve a relatively rapid extinction of a large proportion of organisms that were alive at that time, whereas background extinctions occur at a slower rate and affect a smaller number of species. While asteroid impacts have been implicated in some mass extinctions, other factors such as volcanic activity, glaciation, and changes in sea level and ocean chemistry have also played a role. Mass extinctions account for most species that have gone extinct, but this does not mean that all other extinctions are background extinctions.

How Do Mass Extinctions Differ from Background Extinctions