Indeed, of all the species that have ever lived during the 600 million years of the fossil record, only about 2 to 4 per cent survive today.
(all the species; have lived; T:during the 600 million years of the fossil record; T:ever) (only about 2 to 4 per cent; survive; T:today)
all the species only about 2 to 4 per cent
have lived survive
T:during the 600 million years of the fossil record T:ever
T:today