how vast number of plant and animal species have existed on earth for several thousands of years? Share with your friends Share 6 Shivali answered this Over 7 million species have existed on earth. 5 View Full Answer Sumayya.s answered this according to IUCN (2004) there r 1.5 million species on earth . but according to Robert May , there r 7 million species exist on earth. 1
