What is the total number of living species?

According to chapter 1 of the Global Biodiversity Outlook 1 of The Convention on Biological Diversity, 2007-05-19 (http://www.cbd.int/gbo1/chap-01.shtml), the approximate number of described species is 1.74 million, and the estimate total of existing species, 14 million. These estimates are inevitably incomplete, because new species will have been described since publication of any checklist and more are continually being described; most groups of organisms lack a list of species and numbers are even more approximate.