万物简史英文版_比尔·布莱森-第69章

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nearest　order　of　magnitude；鈥潯�in　the　words　of　edward　o。　wilson鈥攐f　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鈥檚　plant　and　animal　species　may　still　await　discovery。

of　the　organisms　that　we　do　know　about；　more　than　99　in　100　are　only　sketchilydescribed鈥斺�渁　scientific　name；　a　handful　of　specimens　in　a　museum；　and　a　few　scraps　ofdescription　in　scientific　journals鈥潯�is　how　wilson　describes　the　state　of　our　knowledge。　in　thediversity　of　life；　he　estimated　the　number　of　known　species　of　all　types鈥攑lants；　insects；microbes；　algae；　everything鈥攁t　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鈥檛　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　are　in　their　fields；　then　add　the　totals。　many　people　have　in　fact　done　so。

the　problem　is　that　seldom　do　any　two　e　up　with　matching　figures。　some　sources　put　thenumber　of　known　types　of　fungi　at　70；000；　others　at　100；000鈥攏early　half　as　many　again。　youcan　find　confident　assertions　that　the　number　of　described　earthworm　species　is　4；000　andequally　confident　assertions　that　the　figure　is　12；000。　for　insects；　the　numbers　run　from750；000　to　950；000　species。　these　are；　you　understand；　supposedly　the　known　number　ofspecies。　for　plants；　the　monly　accepted　numbers　range　from　248；000　to　265；000。　thatmay　not　seem　too　vast　a　discrepancy；　but　it鈥檚　more　than　twenty　times　the　number　of　floweringplants　in　the　whole　of　north　america。

putting　things　in　order　is　not　the　easiest　of　tasks。　in　the　early　1960s；　colin　groves　of　theaustralian　national　university　began　a　systematic　survey　of　the　250…plus　known　species　ofprimate。　oftentimes　it　turned　out　that　the　same　species　had　been　described　more　than　once鈥�sometimes　several　times鈥攚ithout　any　of　the　discoverers　realizing　that　they　were　dealing　withan　animal　that　was　already　known　to　science。　it　took　groves　four　decades　to　untangleeverything；　and　that　was　with　a　paratively　small　group　of　easily　distinguished；　generallynoncontroversial　creatures。　goodness　knows　what　the　results　would　be　if　anyone　attempted　asimilar　exercise　with　the　planet鈥檚　estimated　20；000　types　of　lichens；　50；000　species　ofmollusk；　or　400；000…plus　beetles。

what　is　certain　is　that　there　is　a　great　deal　of　life　out　there；　though　the　actual　quantities　arenecessarily　estimates　based　on　extrapolations鈥攕ometimes　exceedingly　expansiveextrapolations。　in　a　well…known　exercise　in　the　1980s；　terry　erwin　of　the　smithsonianinstitution　saturated　a　stand　of　nineteen　rain　forest　trees　in　panama　with　an　insecticide　fog；then　collected　everything　that　fell　into　his　nets　from　the　canopy。　among　his　haul　（actuallyhauls；　since　he　repeated　the　experiment　seasonally　to　make　sure　he　caught　migrant　species）were　1；200　types　of　beetle。　based　on　the　distribution　of　beetles　elsewhere；　the　number　ofother　tree　species　in　the　forest；　the　number　of　forests　in　the　world；　the　number　of　other　insecttypes；　and　so　on　up　a　long　chain　of　variables；　he　estimated　a　figure　of　30　million　species　ofinsects　for　the　entire　planet鈥攁　figure　he　later　said　was　too　conservative。　others　using　thesame　or　similar　data　have　e　up　with　figures　of　13　million；　80　million；　or　100　millioninsect　types；　underlining　the　conclusion　that　however　carefully　arrived　at；　such　figuresinevitably　owe　at　least　as　much　to　supposition　as　to　science。

according　to　the　wall　street　journal；　the　world　has　鈥渁bout　10；000　active　taxonomists鈥濃�攏ot　a　great　number　when　you　consider　how　much　there　is　to　be　recorded。　but；　the　journaladds；　because　of　the　cost　（about　2；000　per　species）　and　paperwork；　only　about　fifteenthousand　new　species　of　all　types　are　logged　per　year。

鈥渋t鈥檚　not　a　biodiversity　crisis；　it鈥檚　a　taxonomist　crisis！鈥潯�barks　koen　maes；　belgian…bornhead　of　invertebrates　at　the　kenyan　national　museum　in　nairobi；　whom　i　met　briefly　on　avisit　to　the　country　in　the　autumn　of　2002。　there　were　no　specialized　taxonomists　in　thewhole　of　africa；　he　told　me。　鈥渢here　was　one　in　the　ivory　coast；　but　i　think　he　has　retired；鈥潯�hesaid。　it　takes　eight　to　ten　years　to　train　a　taxonomist；　but　none　are　ing　along　in　africa。

鈥渢hey　are　the　real　fossils；鈥潯�maes　added。　he　himself　was　to　be　let　go　at　the　end　of　the　year；　hesaid。　after　seven　years　in　kenya；　his　contract　was　not　being　renewed。　鈥渘o　funds；鈥潯�maesexplained。

writing　in　the　journal　nature　last　year；　the　british　biologist　g。　h。　godfray　noted　that　thereis　a　chronic　鈥渓ack　of　prestige　and　resources鈥潯�for　taxonomists　everywhere。　in　consequence；鈥渕any　species　are　being　described　poorly　in　isolated　publications；　with　no　attempt　to　relate　anew　taxon2to　existing　species　and　classifications。鈥潯�moreover；　much　of　taxonomists鈥櫋�time　istaken　up　not　with　describing　new　species　but　simply　with　sorting　out　old　ones。　many；according　to　godfray；　鈥渟pend　most　of　their　career　trying　to　interpret　the　work　of　nineteenth…century　systematicists：　deconstructing　their　often　inadequate　published　descriptions　orscouring　the　world鈥檚　museums　for　type　material　that　is　often　in　very　poor　condition。鈥潯�godfrayparticularly　stresses　the　absence　of　attention　being　paid　to　the　systematizing　possibilities　ofthe　internet。　the　fact　is　that　taxonomy　by　and　large　is　still　quaintly　wedded　to　paper。

2the　formal　word　for　a　zoological　category；　such　as　phylum　or　genus。　the　plural　is　taxa。

in　an　attempt　to　haul　things　into　the　modern　age；　in　2001　kevin　kelly；　cofounder　of　wiredmagazine；　launched　an　enterprise　called　the　all　species　foundation　with　the　aim　of　findingevery　living　organism　and　recording　it　on　a　database。　the　cost　of　such　an　exercise　has　beenestimated　at　anywhere　from　2　billion　to　as　much　as　50　billion。　as　of　the　spring　of　2002；　thefoundation　had　just　1。2　million　in　funds　and　four　full…time　employees。　if；　as　the　numberssuggest；　we　have　perhaps　100　million　species　of　insects　yet　to　find；　and　if　our　rates　ofdiscovery　continue　at　the　present　pace；　we　should　have　a　definitive　total　for　insects　in　a　littleover　fifteen　thousand　years。　the　rest　of　the　animal　kingdom　may　take　a　little　longer。

so　why　do　we　know　as　little　as　we　do？　there　are　nearly　as　many　reasons　as　there　areanimals　left　to　count；　but　here　are　a　few　of　the　principal　causes：

most　living　things　are　small　and　easily　overlooked。in　practical　terms；　this　is　not　always　abad　thing。　you　might　not　slumber　quite　so　contentedly　if　you　were　aware　that　your　mattress　ishome　to　perhaps　two　million　microscopic　mites；　which　e　out　in　the　wee　hours　to　sup　onyour　sebaceous　oils　and　feast　on　all　those　lovely；　crunchy　flakes　of　skin　that　you　shed　as　youdoze　and　toss。　your　pillow　alone　may　be　home　to　forty　thousand　of　them。　（to　them　your　headis　just　one　large　oily　bon…bon。）　and　don鈥檛　think　a　clean　pillowcase　will　make　a　difference。　tosomething　on　the　scale　of　bed　mites；　the　weave　of　the　tightest　human　fabric　looks　like　ship鈥檚rigging。　indeed；　if　your　pillow　is　six　years　old鈥攚hich　is　apparently　about　the　average　age　fora　pillow鈥攊t　has　been　estimated　that　one…tenth　of　its　weight　will　be　made　up　of　鈥渟loughedskin；　living　mites；　dead　mites　and　mite　dung；鈥潯�to　quote　the　man　who　did　the　measuring；　dr。

john　maunder　of　the　british　medical　entomology　center。　（but　at　least　they　areyour　mites。

think　of　what　you　snuggle　up　with　each　time　you　climb　into　a　motel　bed。）3these　mites　havebeen　with　us　since　time　immemorial；　but　they　weren鈥檛　discovered　until　1965。

if　creatures　as　intimately　associated　with　us　as　bed　mites　escaped　our　notice　until　the　age　ofcolor　television；　it鈥檚　hardly　surprising　that　most　of　the　rest　of　the　small…scale　world　is　barelyknown　to　us。　go　out　into　a　woods鈥攁ny　woods　at　all鈥攂end　down　and　scoop　up　a　handful　ofsoil；　and　you　will　be　holding　up　to　10　billion　bacteria；　most　of　them　unknown　to　science。　yoursample　will　also　contain　perhaps　a　million　plump　yeasts；　some　200；000　hairy　little　fungiknown　as　molds；　perhaps　10；000　protozoans　（of　which　the　most　familiar　is　the　amoeba）；　andassorted　rotifers；　flatworms；　roundworms；　and　other　microscopic　creatures　known　collectivelyas　cryptozoa。　a　large　portion　of　these　will　also　be　unknown。

the　most　prehensive　handbook　of　microorganisms；　bergey鈥檚　manual　of　systematicbacteriology；　lists　about　4；000　types　of　bacteria。　in　the　1980s；　a　pair　of　norwegian　scientists；jostein　goks？yr　and　vigdis　torsvik；　collected　a　gram　of　random　soil　from　a　beech　forest　neartheir　lab　in　bergen　and　carefully　analyzed　its　bacterial　content。　they　found　that　this　singlesmall　sample　contained　between　4；000　and　5；000　separate　bacterial　species；　more　than　in　thewhole　of　bergey鈥檚　manual。　they　then　traveled　to　a　coastal　location　a　few　miles　away；scooped　up　another　gram　of　earth；　and　found　that　it　contained　4；000　to　5；000　other　species。　asedward　o。　wilson　observes：　鈥渋f　over　9；000　microbial　types　exist　in　two　pinches　of　substratefrom　two　localities　in　norway；　how　many　more　await　discovery　in　other；　radically　differenthabitats？鈥潯�well；　according　to　one　estimate；　it　could　be　as　high　as　400　million。

3we　are　actually　getting　worse　at　some　matters　of　hygiene。　dr。　maunder　believes　that　the　move　toward　low…temperature　washing　machine　detergents　has　encouraged　bugs　to　proliferate。　as　he　puts　it：　〃if　you　wash　lousyclothing　at　low　temperatures；　all　you　get　is　cleaner　lice。〃we　don鈥檛　look　in　the　right　places。　in　the　diversity　of　life；　wilson　describes　how　onebotanist　spent　a　few　days　tramping　around　ten　hectares　of　jungle　in　borneo　and　discovered　athousand　new　species　of　flowering　plant鈥攎ore　than　are　found　in　the　whole　of　northamerica。　the　plants　weren鈥檛　hard　to　find。　it鈥檚　just　that　no　one　had　looked　there　before。　koenmaes　of　the　kenyan　national　museum　told　me　that　he　went　to　one　cloud　forest；　asmountaintop　forests　are　known　in　kenya；　and　in　a　half　hour　鈥渙f　not　particularly　dedicatedlooking鈥潯�found　four　new　species　of　millipedes；　three　representing　new　genera；　and　one　newspecies　of　tree。　鈥渂ig　tree；鈥潯�he　added；　and　shaped　his　arms　as　if　about　to　dance　with　a　verylarge　partner。　cloud　forests　are　found　on　the　tops　of　plateaus　and　have　sometimes　beenisolated　for　millions　of　years。　鈥渢hey　provide　the　ideal　climate　for　biology　and　they　havehardly　been　studied；鈥潯�he　said。

overall；　tropical　rain　forests　cover　only　about　6　percent　of　earth鈥檚　surface；　but　harbor　morethan　half　of　its　animal　life　and　about　two…thirds　of　its　flowering　plants；　and　most　of　this　liferemains　unknown　to　us　because　too　few　researchers　spend　time　in　them。　not　incidentally；much　of　this　could　be　quite　valuable。　at　least　99　percent　of　flowering　plants　have　never　beentested　for　their　medicinal　properties。　because　they　can鈥檛　flee　from　predators；　plants　have　hadto　contrive　chemical　defenses；　and　so　are　particularly　enriched　in　intriguing　pounds。　evennow　nearly　a　quarter　of　all　prescribed　medicines　are　derived　from　just　forty　plants；　withanother　16　percent　ing　fro