按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！
1842 proclaimed a new set of rules called thestricklandian code； but the french saw this as highhanded； and the société zoologiquecountered with its own conflicting code。 meanwhile； the american ornithological society； forobscure reasons； decided to use the 1758 edition of systema naturae as the basis for all itsnaming； rather than the 1766 edition used elsewhere； which meant that many american birdsspent the nineteenth century logged in different genera from their avian cousins in europe。
not until 1902； at an early meeting of the international congress of zoology； did naturalistsbegin at last to show a spirit of promise and adopt a universal code。
taxonomy is described sometimes as a science and sometimes as an art； but really it’s abattleground。 even today there is more disorder in the system than most people realize。 takethe category of the phylum； the division that describes the basic body plans of all organisms。
a few phyla are generally well known； such as mollusks （the home of clams and snails）；arthropods （insects and crustaceans）； and chordates （us and all other animals with a backboneor protobackbone）； though things then move swiftly in the direction of obscurity。 among thelatter we might list gnathostomulida （marine worms）； cnidaria （jellyfish； medusae；anemones； and corals）； and the delicate priapulida （or little “penis worms”）。 familiar or not；these are elemental divisions。 yet there is surprisingly little agreement on how many phylathere are or ought to be。 most biologists fix the total at about thirty； but some opt for a numberin the low twenties； while edward o。 wilson in the diversity of life puts the number at asurprisingly robust eighty…nine。 it depends on where you decide to make your divisions—whether you are a “lumper” or a “splitter；” as they say in the biological world。
at the more workaday level of species； the possibilities for disagreements are even greater。
whether a species of grass should be called aegilops incurva； aegilops incurvata； or aegilopsovata may not be a matter that would stir many nonbotanists to passion； but it can be a sourceof very lively heat in the right quarters。 the problem is that there are five thousand species ofgrass and many of them look awfully alike even to people who know grass。 in consequence；some species have been found and named at least twenty times； and there are hardly any； itappears； that haven’t been independently identified at least twice。 the two…volume manual ofthe grasses of the united states devotes two hundred closely typeset pages to sorting out allthe synonymies； as the biological world refers to its inadvertent but quite monduplications。 and that is just for the grasses of a single country。
to deal with disagreements on the global stage； a body known as the internationalassociation for plant taxonomy arbitrates on questions of priority and duplication。 at1to illustrate； humans are in the domain eucarya； in the kingdom animalia； in the phylum chordata； in thesubphylum vertebrata； in the class mammalia； in the order primates； in the family hominidae； in the genus homo；in the species sapiens。 （the convention； im informed； is to italicize genus and species names； but not those ofhigher divisions。） some taxonomists employ further subdivisions： tribe； suborder； infraorder； parvorder； andmore。
intervals it hands down decrees； declaring that zauschneria californica （a mon plant inrock gardens） is to be known henceforth as epilobium canum or that aglaothamniontenuissimum may now be regarded as conspecific with aglaothamnion byssoides； but notwithaglaothamnion pseudobyssoides。 normally these are small matters of tidying up thatattract little notice； but when they touch on beloved garden plants； as they sometimes do；shrieks of outrage inevitably follow。 in the late 1980s the mon chrysanthemum wasbanished （on apparently sound scientific principles） from the genus of the same name andrelegated to the paratively drab and undesirable world of the genus dendranthema。
chrysanthemum breeders are a proud and numerous lot； and they protested to the real ifimprobable…sounding mittee on spermatophyta。 （there are also mittees forpteridophyta； bryophyta； and fungi； among others； all reporting to an executive called therapporteur…général； this is truly an institution to cherish。） although the rules of nomenclatureare supposed to be rigidly applied； botanists are not indifferent to sentiment； and in 1995 thedecision was reversed。 similar adjudications have saved petunias； euonymus； and a popularspecies of amaryllis from demotion； but not many species of geraniums； which some yearsago were transferred； amid howls； to the genus pelargonium。 the disputes are entertaininglysurveyed in charles elliott’s the potting…shed papers。
disputes and reorderings of much the same type can be found in all the other realms of theliving； so keeping an overall tally is not nearly as straightforward a matter as you mightsuppose。 in consequence； the rather amazing fact is that we don’t have the faintest idea—“noteven to the nearest order of magnitude；” in the words of edward o。 wilson—of the number ofthings that live on our planet。 estimates range from 3 million to 200 million。 moreextraordinary still； according to a report in the economist； as much as 97 percent of theworld’s plant and animal species may still await discovery。
of the organisms that we do know about； more than 99 in 100 are only sketchilydescribed—“a scientific name； a handful of specimens in a museum； and a few scraps ofdescription in scientific journals” is how wilson describes the state of our knowledge。 in thediversity of life； he estimated the number of known species of all types—plants； insects；microbes； algae； everything—at 1。4 million； but added that that was just a guess。 otherauthorities have put the number of known species slightly higher； at around 1。5 million to 1。8million； but there is no central registry of these things； so nowhere to check numbers。 in short；the remarkable position we find ourselves in is that we don’t actually know what we actuallyknow。
in principle you ought to be able to go to experts in each area of specialization； ask howmany species there a