"The total number of land-dwelling mammals birds , reptiles , and amphibian species is less than 20,000 or so ."
"I believe the current number is around 24,000 for those three groups . But anyways , if the ark only took kinds , rather than species , then that 's an awful lot of speciation occuring very rapidly ."
"is less than 20,000 or so ."
"the current number is around 24,000 for those three groups ."