One of the concerns about the loss of species is that we don't even
know how many species we have to start with -- meaning its hard to even
set baselines for biodiversity.
And now, to underscore how little we know, Craig Ventor of Human Genome
fame, reported in Science last week that in a sample of sea water in the
crystal clear, seemingly lifeless waters of the Sargasso Sea are found
at least 1800 species of organisms. Which leads him to the conclusion
that "more than 99 percent of species remain to be discovered."