How many species are on planet Earth? To be honest – we really don’t know. Estimates have been cited as high at 100 million species, and as low as 3 million. Recent estimates suggest that there are probably around 8.7 million eukaryotic species on the planet, but if we add the bacteria, that will undoubtably be higher. While we may never now the total number of species – we can keep track of how many we have identified to date.
The OpenTreeOfLife.org recently published a study which suggests that the most accurate estimate of the number of these species we have identified, to date, is 2.3 million.
The OpenTree of Life site is a very useful one if you are doing research on systematics or want to understand some basic taxonomic relationships. But if you want to get more information on a specific species, or group of organisms, then I recommend that you check out the Encyclopedia of Life’s page.
Scientists publish most comprehensive ‘tree of life’ yet, with 2.3 million species; Science Alert (Sept 2015)
Encyclopedia of Life Biodiversity Resources for Biology Teachers: Ricochet Science (Jan 2013)
- Number of species on Earth tagged at 8.7 million: Nature (August 2011)
- Tree of Life Diagram: OpenTreeOfLife.org