Extinction and extirpation per years

Canadian Species at Risk Act uses categorizes:
Extinction = occurs when the last member of a species dies and the species ceases to exist
Extirpation = the disappearance of a particular population from a given area, but not the entire species globally
Endangered = species in imminent danger of becoming extirpated or extinct
Threatened = species likely to become endangered in the near future

Paleontologists estimate 99% of all species that ever lived are now extinct
Background rate of extinction = natural extinctions for a variety of reasons
1 species out of 1,000 mammal and marine species would go extinct every 1,000 to 10,000 years
1 extinction per 1 to 10 million species for mammals and marine species

Earth has experienced five previous mass extinction episodes
In the past 440 million years, mass extinctions have eliminated at least 50% of all species
Today’s mass extinction is caused by humans and humans will suffer as a result of it