Psychotria writes: A study published in PLoS provides a new estimate on the number of species inhabiting our planet. The study predicts that there could be approximately 8.7 million eukaryotic species globally. This suggests that some 86% of the species on Earth, and 91% in the ocean, still await formal description and classification. In 2007 E.O. Wilson stated "We live on a mostly unexplored planet." It seems that it may be more unexplored than we thought.