In 1976 I almost burnt down the Smithsonian Institution in Washington. If I had succeeded I imagine that I would now be one of the most famous scientists in the world. Thirty years ago I was a pipe smoker, and the study cubicles in the National Museum of Natural History in the Smithsonian allowed scholars to puff away at their pipes while looking down the microscope. It somehow seemed an appropriate thing to permit. Behind the scenes at the Smithsonian lies a similarly vast labyrinth to that in our Natural History Museum and here, too, are ranks of collections, quietly minding their own business until a visiting expert re-examines them in their labelled drawers. I was interested in looking at trilobite specimens collected years before by one of their staff, E. O. Ulrich. I had my microscope in front of me, and a line of specimens to one hand, while the other picked up the pipe from time to time, and waved it about. It was about as contented a scene as could be imagined. At the end of the day I did what pipe smokers do, which is to tap out the dead pipe into the metal waste-paper bin in the corner of the room. The only problem was that the pipe was not completely dead; I had deposited smouldering scraps of Erinmore Mixture among the discarded pieces of paper in the bin. I shut up for the night and went home. Half an hour later, a passing security man noticed billowing smoke arising from my cubicle; fortunately, the fire was quickly extinguished. It might have been a different story had the receptacle been a woven basket. I overheard mumbled gossip about me for the next few days.
Had I destroyed the United States’ national collections of natural history the damage would have been irreparable, not just for the USA but for the world. The most important single feature of the great collections is that they form the basis for naming the living world. They are the reference system for nature. The curated specimens are the ground truth for the scientific names of animals, plants and minerals. The naming of organisms is called taxonomy, and their arrangement in classificatory order is called systematics. All those cabinets I passed when I explored the Natural History Museum in London were the storehouses for the still-growing catalogue of what is now often termed biodiversity, the richness of the living world. Although it achieves a lot besides, the basic justification of research in the reference collections of natural history museums is taxonomic. So if my Erinmore Mixture had sparked off a major conflagration much of the basis for the names given to fauna and flora around the world would have gone up in smoke. It would have taken years to sort out. Some museums were bombed during the Second World War, such as the Humboldt Museum in Berlin, and lost many specimens; the resulting taxonomic confusion is still being worked out. That is why museums place such emphasis on the security of their collections; it is an acknowledgement of their permanence: hence the special keys and the security codes.
The taxonomic mission can be briefly stated: to make known all the species on Earth. It sounds easy. This is, of course, only the beginning of finding out about life, because there lies beyond identification so much more, such as how animals live – their ecology – or why there are different species in different parts of the world. Often the taxonomy is inextricably entwined with these other aspects, for example, when two closely related species may be distinguished by having subtly different ecology. European ornithologists will know the instance of the exceedingly similar marsh (Parus montanus) and willow (Parus palustris) tits, which are readily distinguishable only by their songs. Recognition of species is always the first step in understanding the complex interactions of the biological world. Just as you need a vocabulary before you can speak a language, so it is necessary to have a dictionary of species before you can read the complex book of nature.
Nor is the taxonomic mission as simple as it sounds. There are a few groups of organisms – birds and mammals come to mind – where large size and intensive study over many years means that the vast majority of species have been named and described. Even here there can be surprises, as when a new species of large ungulate mammal was discovered in the jungles of Vietnam a few years ago, or when in 2005 a pristine part of New Guinea was explored for the first time and a rare bird of paradise brought ‘back from the dead’. Bats are turning out to have many more species than was originally thought. I went with a research student into the cloud forest of Ecuador to see a new bat species with the longest tongue in the world that had apparently evolved to feed from (and pollinate) an extraordinary flower with a matching long corolla. It is illustrated in the colour plates. But as a rule there are very few new mammal or bird species to discover, and global concern is rather with conserving those that are known already: by any standard this is a big enough matter.
With other groups of organisms the story is different. The insects are the most obvious example: small, teeming and unnoticed they fill almost every habitat on earth. I will choose one example, from a cast of thousands. You have to be a special kind of person to love fungus gnats, but if you look at mushrooms growing in woods you will certainly see these tiny insects flying around the fungi. They are abundant. Most of us encounter these particular creatures as irritating ‘wormholes’ occupied by their larvae that might spoil an otherwise nice-looking field mushroom. But they still fulfil an important function in nature, and they provide a foodstuff for insectivores in their turn. They are a link in the chain. But how many species are there? And how do you tell them apart? Do they feed on lots of different fungi or are there specialists for particular kinds of fungi? All these questions require the attention of a knowledgeable taxonomist, a microscope, and skill. Tiny differences in the wings or the hairs on the legs may be crucial in the identification of a species. With luck, expertly identified specimens will finish up as collections in a cabinet marked Family Mycetophilidae (‘mushroom lover’) in the Natural History Museum. As to how many species there are, well, at the last count there were 531 different fungus gnats in the United Kingdom alone, and more being added all the time. It is scarcely surprising that there are many more species still remaining to be discovered in the wild. If a new bat can be discovered in Ecuador’s cloud forest,