In “Species count put at 8.7 million” (BBC News, August 23, 2011), Richard Black reports,
The natural world contains about 8.7 million species, according to a new estimate described by scientists as the most accurate ever.
But the vast majority have not been identified – and cataloguing them all could take more than 1,000 years.
Oh well, then, we have time to be sure we are headed up the right path in identifying them. Nothing like a millennium. How did they arrive at the figure?
The number comes from studying relationships between the branches and leaves of the “family tree of life”.
They excluded bacteria, and some other life forms, then
The higher up this hierarchical tree of life you look, the rarer new discoveries become – hardly surprising, as a discovery of a new species will be much more common than the discovery of a totally new phylum or class.
The researchers quantified the relationship between the discovery of new species and the discovery of new higher groups such as phyla and orders, and then used it to predict how many species there are likely to be.
Of course, that might not work, as a system. Many phyla or classes might be poorly represented in present-day species, so a general method like this would inevitably inflate numbers. How many species of relatives of the duck-billed platypus should there be, using their method?
But it’s an interesting approach to try, and certainly deserves better than the comment by top Brit toff, Lord (Robert) May, former Royal Society president:
It is a remarkable testament to humanity’s narcissism that we know the number of books in the US Library of Congress on 1 February 2011 was 22,194,656, but cannot tell you – to within an order of magnitude – how many distinct species of plants and animals we share our world with.
Look, toff, a library is a catalogued collection of books. Of course the librarians should know, at the touch of a key, the current total.
Have life forms ever lined up to be counted since the fabled days of Noah’s Ark?
Researchers don’t know how many species there are for exactly the same reason that the super of a nearby apartment building doesn’t know how many rats infest the dumpster. They never fill out the census forms.
But we bet that the toff rehearsed his signature line all morning. A better Britain needs smarter toffs.
Note: The researchers came up with this interesting table:
Animals: 7.77 million (12% described)
Fungi: 0.61 million (7% described)
Plants: 0.30 million (70% described)
Protozoa: 0.04 million (22% described)
Chromists: 0.03 million (50% described)
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