万物简史英文版_比尔·布莱森-第82章

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　milankovitch　cycles鈥攖hat　it　is　asdifficult　to　prehend　the　events　of　the　past　as　it　is　to　predict　those　of　the　future。　much　issimply　beyond　us。　take　antarctica。　for　at　least　twenty　million　years　after　it　settled　over　thesouth　pole　antarctica　remained　covered　in　plants　and　free　of　ice。　that　simply　shouldn鈥檛　havebeen　possible。

no　less　intriguing　are　the　known　ranges　of　some　late　dinosaurs。　the　british　geologiststephen　drury　notes　that　forests　within　10　degrees　latitude　of　the　north　pole　were　home　togreat　beasts；　including　tyrannosaurus　rex。　鈥渢hat　is　bizarre；鈥潯�he　writes；　鈥渇or　such　a　highlatitude　is　continually　dark　for　three　months　of　the　year。鈥潯�moreover；　there　is　now　evidencethat　these　high　latitudes　suffered　severe　winters。　oxygen　isotope　studies　suggest　that　theclimate　around　fairbanks；　alaska；　was　about　the　same　in　the　late　cretaceous　period　as　it　isnow。　so　what　was　tyrannosaurus　doing　there？　either　it　migrated　seasonally　over　enormousdistances　or　it　spent　much　of　the　year　in　snowdrifts　in　the　dark。　in　australia鈥攚hich　at　thattime　was　more　polar　in　its　orientation鈥攁　retreat　to　warmer　climes　wasn鈥檛　possible。　howdinosaurs　managed　to　survive　in　such　conditions　can　only　be　guessed。

one　thought　to　bear　in　mind　is　that　if　the　ice　sheets　did　start　to　form　again　for　whateverreason；　there　is　a　lot　more　water　for　them　to　draw　on　this　time。　the　great　lakes；　hudson　bay；the　countless　lakes　of　canada鈥攖hese　weren鈥檛　there　to　fuel　the　last　ice　age。　they　were　createdby　it。

on　the　other　hand；　the　next　phase　of　our　history　could　see　us　melting　a　lot　of　ice　rather　thanmaking　it。　if　all　the　ice　sheets　melted；　sea　levels　would　rise　by　two　hundred　feet鈥攖he　heightof　a　twenty…story　building鈥攁nd　every　coastal　city　in　the　world　would　be　inundated。　morelikely；　at　least　in　the　short　term；　is　the　collapse　of　the　west　antarctic　ice　sheet。　in　the　past　fiftyyears　the　waters　around　it　have　warmed　by　2。5　degrees　centigrade；　and　collapses　haveincreased　dramatically。　because　of　the　underlying　geology　of　the　area；　a　large…scale　collapseis　all　the　more　possible。　if　so；　sea　levels　globally　would　rise鈥攁nd　pretty　quickly鈥攂y　betweenfifteen　and　twenty　feet　on　average。

the　extraordinary　fact　is　that　we　don鈥檛　know　which　is　more　likely；　a　future　offering　us　eonsof　perishing　frigidity　or　one　giving　us　equal　expanses　of　steamy　heat。　only　one　thing　iscertain：　we　live　on　a　knife　edge。

in　the　long　run；　incidentally；　ice　ages　are　by　no　means　bad　news　for　the　planet。　they　grindup　rocks　and　leave　behind　new　soils　of　sumptuous　richness；　and　gouge　out　fresh　water　lakesthat　provide　abundant　nutritive　possibilities　for　hundreds　of　species　of　being。　they　act　as　aspur　to　migration　and　keep　the　planet　dynamic。　as　tim　flannery　has　remarked：　鈥渢here　is　onlyone　question　you　need　ask　of　a　continent　in　order　to　determine　the　fate　of　its　people：　鈥榙id　youhave　a　good　ice　age？鈥櫋♀�潯�and　with　that　in　mind；　it鈥檚　time　to　look　at　a　species　of　ape　that　trulydid。

xia锛�锛砲u锛痶x锛础ｏ迹om



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just　before　christmas　1887；　a　young　dutch　doctor　with　an　un…dutch　name；　marieeug猫ne　fran？ois　thomas　dubois；　arrived　in　sumatra；　in　the　dutch　east　indies；　with　theintention　of　finding　the　earliest　human　remains　on　earth。

1several　things　were　extraordinary　about　this。　to　begin　with；　no　one　had　ever　gone　lookingfor　ancient　human　bones　before。　everything　that　had　been　found　to　this　point　had　been　foundaccidentally；　and　nothing　in　dubois鈥檚　background　suggested　that　he　was　the　ideal　candidate　tomake　the　process　intentional。　he　was　an　anatomist　by　training　with　no　background　inpaleontology。　nor　was　there　any　special　reason　to　suppose　that　the　east　indies　would　holdearly　human　remains。　logic　dictated　that　if　ancient　people　were　to　be　found　at　all；　it　would　beon　a　large　and　long…populated　landmass；　not　in　the　parative　fastness　of　an　archipelago。

dubois　was　driven　to　the　east　indies　on　nothing　stronger　than　a　hunch；　the　availability　ofemployment；　and　the　knowledge　that　sumatra　was　full　of　caves；　the　environment　in　whichmost　of　the　important　hominid　fossils　had　so　far　been　found。　what　is　most　extraordinary　in　allthis鈥攏early　miraculous；　really鈥攊s　that　he　found　what　he　was　looking　for。

at　the　time　dubois　conceived　his　plan　to　search　for　a　missing　link；　the　human　fossil　recordconsisted　of　very　little：　five　inplete　neandertal　skeletons；　one　partial　jawbone　of　uncertainprovenance；　and　a　half…dozen　ice…age　humans　recently　found　by　railway　workers　in　a　cave　at　acliff　called　cro…magnon　near　les　eyzies；　france。　of　the　neandertal　specimens；　the　bestpreserved　was　sitting　unremarked　on　a　shelf　in　london。　it　had　been　found　by　workers　blastingrock　from　a　quarry　in　gibraltar　in　1848；　so　its　preservation　was　a　wonder；　but　unfortunatelyno　one　yet　appreciated　what　it　was。　after　being　briefly　described　at　a　meeting　of　the　gibraltarscientific　society；　it　had　been　sent　to　the　hunterian　museum　in　london；　where　it　remainedundisturbed　but　for　an　occasional　light　dusting　for　over　half　a　century。　the　first　formaldescription　of　it　wasn鈥檛　written　until　1907；　and　then　by　a　geologist　named　william　sollas鈥渨ith　only　a　passing　petency　in　anatomy。鈥�

so　instead　the　name　and　credit　for　the　discovery　of　the　first　early　humans　went　to　theneander　valley　in　germany鈥攏ot　unfittingly；　as　it　happens；　for　by　uncanny　coincidenceneander　in　greek　means　鈥渘ew　man。鈥潯�there　in　1856　workmen　at　another　quarry；　in　a　cliff　faceoverlooking　the　d眉ssel　river；　found　some　curious…looking　bones；　which　they　passed　to　alocal　schoolteacher；　knowing　he　had　an　interest　in　all　things　natural。　to　his　great　credit　theteacher；　johann　karl　fuhlrott；　saw　that　he　had　some　new　type　of　human；　though　quite　what　itwas；　and　how　special；　would　be　matters　of　dispute　for　some　time。

many　people　refused　to　accept　that　the　neandertal　bones　were　ancient　at　all。　august　mayer；a　professor　at　the　university　of　bonn　and　a　man　of　influence；　insisted　that　the　bones　were1though　dutch；　dubois　was　from　eijsden；　a　town　bordering　the　french…speaking　part　of　belgium。

merely　those　of　a　mongolian　cossack　soldier　who　had　been　wounded　while　fighting　ingermany　in　1814　and　had　crawled　into　the　cave　to　die。　hearing　of　this；　t。　h。　huxley　inengland　drily　observed　how　remarkable　it　was　that　the　soldier；　though　mortally　wounded；　hadclimbed　sixty　feet　up　a　cliff；　divested　himself　of　his　clothing　and　personal　effects；　sealed　thecave　opening；　and　buried　himself　under　two　feet　of　soil。　another　anthropologist；　puzzlingover　the　neandertal鈥檚　heavy　brow　ridge；　suggested　that　it　was　the　result　of　long…term　frowningarising　from　a　poorly　healed　forearm　fracture。　（in　their　eagerness　to　reject　the　idea　of　earlierhumans；　authorities　were　often　willing　to　embrace　the　most　singular　possibilities。　at　about　thetime　that　dubois　was　setting　out　for　sumatra；　a　skeleton　found　in　p茅rigueux　was　confidentlydeclared　to　be　that　of　an　eskimo。　quite　what　an　ancient　eskimo　was　doing　in　southwestfrance　was　never　fortably　explained。　it　was　actually　an　early　cro…magnon。）it　was　against　this　background　that　dubois　began　his　search　for　ancient　human　bones。　hedid　no　digging　himself；　but　instead　used　fifty　convicts　lent　by　the　dutch　authorities。　for　a　yearthey　worked　on　sumatra；　then　transferred　to　java。　and　there　in　1891；　dubois鈥攐r　rather　histeam；　for　dubois　himself　seldom　visited　the　sites鈥攆ound　a　section　of　ancient　human　craniumnow　known　as　the　trinil　skullcap。　though　only　part　of　a　skull；　it　showed　that　the　owner　hadhad　distinctly　nonhuman　features　but　a　much　larger　brain　than　any　ape。　dubois　called　itanthropithecus　erectus　（later　changed　for　technical　reasons　to　pithecanthropus　erectus）　anddeclared　it　the　missing　link　between　apes　and　humans。　it　quickly　became　popularized　as　鈥渏avaman。鈥潯�today　we　know　it　as　homo　erectus。

the　next　year　dubois鈥檚　workers　found　a　virtually　plete　thighbone　that　lookedsurprisingly　modern。　in　fact；　many　anthropologists　think　itis　modern；　and　has　nothing　to　dowith　java　man。　if　it　is　an　erectus　bone；　it　is　unlike　any　other　found　since。　nonetheless　duboisused　the　thighbone　to　deduce鈥攃orrectly；　as　it　turned　out鈥攖hat　pithecanthropus　walkedupright。　he　also　produced；　with　nothing　but　a　scrap　of　cranium　and　one　tooth；　a　model　of　theplete　skull；　which　also　proved　uncannily　accurate。

in　1895；　dubois　returned　to　europe；　expecting　a　triumphal　reception。　in　fact；　he　met　nearlythe　opposite　reaction。　most　scientists　disliked　both　his　conclusions　and　the　arrogant　manner　inwhich　he　presented　them。　the　skullcap；　they　said；　was　that　of　an　ape；　probably　a　gibbon；　andnot　of　any　early　human。　hoping　to　bolster　his　case；　in　1897　dubois　allowed　a　respectedanatomist　from　the　university　of　strasbourg；　gustav　schwalbe；　to　make　a　cast　of　the　skullcap。

to　dubois鈥檚　dismay；　schwalbe　thereupon　produced　a　monograph　that　received　far　moresympathetic　attention　than　anything　dubois　had　written　and　followed　with　a　lecture　tour　inwhich　he　was　celebrated　nearly　as　warmly　as　if　he　had　dug　up　the　skull　himself。　appalled　andembittered；　dubois　withdrew　into　an　undistinguished　position　as　a　professor　of　geology　at　theuniversity　of　amsterdam　and　for　the　next　two　decades　refused　to　let　anyone　examine　hisprecious　fossils　again。　he　died　in　1940　an　unhappy　man。

meanwhile；　and　half　a　world　away；　in　late　1924　raymond　dart；　the　australian…born　head　ofanatomy　at　the　university　of　the　witwatersrand　in　johannesburg；　was　sent　a　small　butremarkably　plete　skull　of　a　child；　with　an　intact　face；　a　lower　jaw；　and　what　is　known　asan　endocast鈥攁　natural　cast　of　the　brain鈥攆rom　a　limestone　quarry　on　the　edge　of　the　kalaharidesert　at　a　dusty　spot　called　taung。　dart　could　see　at　once　that　the　taung　skull　was　not　of　ahomo　erectus　like　dubois鈥檚　java　man；　but　from　an　earlier；　more　apelike　creature。　he　placedits　age　at　two　million　years　and　dubbed　it　australopithecus　africanus；　or　鈥渟outhern　ape　man　ofafrica。鈥潯�in　a　report　to　nature；　dart　called　the　taung　remains　鈥渁mazingly　human鈥潯�andsuggested　the　need　for　an　entirely　new　family；　homo　simiadae　（鈥渢he　man…apes鈥潱�；　toacmodate　the　find。

the　authorities　were　even　less　favorably　disposed　to　dart　than　they　had　been　to　dubois。

nearly　everything　about　his　theory鈥攊ndeed；　nearly　everything　about　dart；　it　appears鈥攁nnoyed　them。　first　he　had　proved　himself　lamentably　presumptuous　by　conducting　theanalysis　himself　rather　than　calling　on　the　help　of　more　worldly　experts　in　europe。　even　hischosen　name；　australopithecus；　showed　a　lack　of　scholarly　application；　bining　as　it　didgreek　and　latin　roots。　above　all；　his　conclusions　flew　in　the　face　of　accepted　wisdom。

humans　and　apes；　it　was　agreed；　had　split　apart　at　least　fifteen　million　years　ago　in　asia。　ifhumans　had　arisen　in　africa；　why；　that　would　make　us　negroid；　for　goodness　sake。　it　wasrather　as　if　someone　working　today　were　to　announce　that　he　had　found　the　ancestral　bones　ofhumans　in；　say；　missouri。　it　just　didn鈥檛　fit　with　what　was　known。

dart鈥檚　sole　supporter　of　note　was　robert　broom；　a　scottish…born　physician　andpaleontologist　of　considerable　intellect　and　cherishably　eccentric　nature。　it　was　broom鈥檚habit；　for　instance；　to　do　his　fieldwork　naked　when　the　weather　was　warm；　which　was　often。

he　was　also　known　for　condu