About 91 Percent of Ocean Species Have Not Been Described

How many kinds of living things are there? In 2011 a team of researchers published an estimate in the peer-reviewed journal PLOS Biology. They noticed that the way species are grouped into larger categories follows a consistent pattern, and used that pattern to predict totals. Their method predicted about 8.7 million species globally, give or take 1.3 million, of which about 2.2 million are marine. Set against the species already catalogued, more than 1.2 million at the time, the results suggested that some 86 percent of existing species on Earth and 91 percent of species in the ocean still await description. This is an estimate, not a count. The authors themselves describe the question as one of the most basic yet elusive in science, and earlier estimates had varied widely.