English Dictionary

mass extinction

noun

(evolutionary theory, geology) A sharp decrease in the total number of species in a relatively short period of time; specifically, a loss of ∼75% of all species on the planet over a geologically interval of less than 3 million years, as a result of a mass extinction event.

The mass extinction event wiped out nearly 75% of all species on Earth.

意味（1）

(evolutionary theory, geology) A sharp decrease in the total number of species in a relatively short period of time; specifically, a loss of ∼75% of all species on the planet over a geologically interval of less than 3 million years, as a result of a mass extinction event.

Preceded by five other mass extinctions and many more small extinction events, the mass extinction currently underway is, on the one hand, like all the others in that it is nothing other than a significant reduction in the number of individual organisms inhabiting the planet and at the same time a significant reduction in the diversity of species made up by those individual organisms.