See great oxidation event. Also destroing x% of species isn't same destroying x% of life. If there are ten species of 2 individuals and 80 individuals of anot

See great oxidation event. Also destroing x% of species isn't same destroying x% of life. If there are ten species of 2 individuals and 80 individuals of another species, you can kill ~90% species while killing only 20% of all life. If you kill 90% of all life you have to kill 90 individuals.