Five hundred million different species of living creatures have appeared on Earth, nearly 99 percent of them vanishing. 

Nearly 99 percent of five hundred million different species of living creatures that appeared on Earth have vanished.

Vanished are nearly 99 percent of the five hundred million different species of living creatures that appeared on Earth.

Of five hundred million different species of living creatures that have appeared on Earth, nearly 99 percent of them have vanished.

Of the five hundred million different species of living creatures that have appeared on Earth, nearly 99 percent have vanished.