How many species are there?
| 16 September, 2011 | Richard P. Grant |
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And does it matter?
There’s a long discussion on the F1000 website about a paper in PLoS Biology on the number of species in the world. Robert May seems to think that the first question a visiting alien species might ask us is, “How many distinct life forms—species—does your planet have?”–rather than the more practical “Have you got change for a fifty billion galactic credit note?”, “Where’s the nearest gas station?” or even “Um, have you guys got nukes yet?”
Why they might be so interested doesn’t seem to concern Lord May, but never mind. Ferdinando Boero, who has a long history, at F1000 and elsewhere, of flying the flag for good and proper taxonomy, evaluated the PLoS Biology paper, acknowledging that knowing this number is important, but adding “the names are even more important!”
Ruben Sommaruga has dissented the article, pointing to the controversy that is discussed on the journal’s website, and suggesting that the authors’ estimate of ~8.7 million is too conservative.
According to the authors, to adequately count and, more importantly describe everything on Earth, “may take as long as 1,200 years and would require 303,000 taxonomists at an approximated cost of US$364 billion.” Ferdinando goes on to say that he thinks this is not a reason to stop counting or describing, and is probably more important than looking for those aliens that might ask us the question. As he says, the quest for medicines has been going on a lot longer, and we wouldn’t have wanted to stop that because it was too difficult, or expensive.
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Sorry to contradict you, Richard. Lord May is at least partly right. We are the aliens that are looking for life in other planets and the main interest to go to other worlds is just to find life, and that’s why these enterprises receive so much funds: we terrestrials like very much to find some species elsewhere, and we send our rockets here and there (spending billions of dollars) just to look for them. If there is life on another planet, and I would be the alien there, I would surely ask how many “kinds” of living beings are there, and I would refer to kingdoms, for instance. If there are just bacterial-like forms… well it is interesting but the difference, the big difference, would be to find the little or large greenish guys that are able to communicate with us. So, maybe, kingdoms and phyla would be more interesting than simply a flat number of species. After a while, then, even the question about the number of species would come out. Anyway, in my evaluation, I referred to “God” (an entity that is even more important than the aliens), and in the Bible he (or she) does not ask us to count the species that are present in the garden of Eden, he asks us to name them!
So, God put us on the planet (like aliens) and asked us to name animals (yes, animals, sorry for the botanists), and not to count them. In our culture (and I do not want to express any judgement here) God is even more important than the aliens (on the dollar it is written: In God we trust, and not: In the Martians we trust) and is surely more influential even than Lord May!
Well, maybe I am wrong… the guys who guess the number receive lots of status, and here we are discussing about their deed, whereas the poor taxonomists, in spite of being on a mission for God, are becoming extinct.
It is paradoxical, though, that Drake’s equation (the guy who guessed how many places are fit for martians to live) is used as a reason to go in space to look for them. Whereas here we say: well, species are so many that naming them is a hopeless job. The nice thing is that the comments to the article usually regard the accuracy of the estimates, and this reminds me of a movie in which the mathematicians in congress were challenging each other to state the largest number in a given time, and the one who won simply said “plus one” after the exhausted challenger stopped saying his number. So, let’s wait for a Nature or Science article where the authors demonstrate, with lots of equations, that the species are 8.7 million, plus one!
Heh. I don’t know about Lord May though, Nando. I think our interest in life on other planets is driven by two motivations: first, to see how different alien life is, and second, to make contact with intelligent life. We’re not so interested in how many species there might be in the first instance. I think a more intelligent first question would be “What’s your genetic material?”
Anyway, I agree it’s important to name and categorize. As fellow FM Jim Woodgett has just pointed out on twitter, how can we conserve species if we don’t know about them?