AP BIOLOGY

Detailed explanation-1: -Scientists have suggested many possible causes for the Great Dying: severe volcanism, a nearby supernova, environmental changes wrought by the formation of a super-continent, the devastating impact of a large asteroid–or some combination of these.

Detailed explanation-2: -The main modern causes of extinction are the loss and degradation of habitat (mainly deforestation), over exploitation (hunting, overfishing), invasive species, climate change, and nitrogen pollution.

Detailed explanation-3: -Mass extinctions-when at least half of all species die out in a relatively short time-have occurred only a handful of times over the course of our planet’s history. The largest mass extinction event happened around 250 million years ago, when perhaps 95 percent of all species went extinct.

Detailed explanation-4: -The ‘Big Five’ mass extinctions There have been five mass extinction events in Earth’s history. At least, since 500 million years ago; we know very little about extinction events in the Precambrian and early Cambrian earlier which predates this. These are called the ‘Big Five’, for obvious reasons.