According to the study, approximately 6.5 million species are found on land, and 2.2 million in the ocean.
The report also indicates that 86 percent of all species on land and 91 percent of those in the seas have yet to be discovered, described or catalogued.
23 August 2011: A UN Environment Programme (UNEP) World Conservation Monitoring Centre (WCMC) researcher has co-authored a paper estimating the number of species on Earth. According to the paper, titled “How Many Species are There on Earth and in the Ocean?,” there are 8.7 million species.
According to the paper, which was authored by Camilo Mora, Derek P. Tittensor, Sina Adl, Alastair G. B. Simpson, and Boris Worm, approximately 6.5 million species are found on land, and 2.2 million in the ocean. The report also indicates that 86 percent of all species on land and 91 percent of those in the seas have yet to be discovered, described or catalogued.
According to a UNEP press release, the authors applied an innovative, validated analytical technique that dramatically narrows the range of previous species estimates. The technique involved identifying numerical patterns within the taxonomic classification system (which ranks groups of life upwards from species to genus, family, order, class, phylum, kingdom and domain). By analyzing the taxonomic clustering of the 1.2 million species included in the Catalogue of Life and the World Register of Marine Species, the researchers discovered numerical relationships between the more complete higher taxonomic levels and the species level. UNEP says the approach accurately predicted the number of species in several well-studied groups such as mammals, fishes and birds, providing confidence in the method. [Publication: How Many Species Are There on Earth and in the Ocean?] [UNEP Press Release]