《A Short History of Nearly Everything》第144章

2it　didn’t　last。
after　about　a　decade　of　parative　calm；　paleoanthropology　embarked　on　another　periodof　swift　and　prolific　discovery；　which　hasn’t　abated　yet。　the　1960s　produced　homo　habilis；thought　by　some　to　be　the　missing　link　between　apes　and　humans；　but　thought　by　others　not　tobe　a　separate　species　at　all。　then　came　（among　many　others）　homo　ergaster；　homolouisleakeyi；　homo　rudolfensis；　homo　microcranus；　and　homo　antecessor；　as　well　as　a　raft　ofaustralopithecines：　a。afarensis；　a。　praegens；　a。　ramidus；　a。　walkeri；　a。　anamensis；　and　stillothers。　altogether；　some　twenty　types　of　hominid　are　recognized　in　the　literature　today。
unfortunately；　almost　no　two　experts　recognize　the　same　twenty。
some　continue　to　observe　the　two　hominid　genera　suggested　by　howell　in　1960；　but　othersplace　some　of　the　australopithecines　in　a　separate　genus　called　paranthropus　；　and　still　othersadd　an　earlier　group　called　ardipithecus。　some　put　praegens　into　australopithecus　and　someinto　a　new　classification；　homo　antiquus；　but　most　don’t　recognize　praegens　as　a　separatespecies　at　all。　there　is　no　central　authority　that　rules　on　these　things。　the　only　way　a　namebees　accepted　is　by　consensus；　and　there　is　often　very　little　of　that。
a　big　part　of　the　problem；　paradoxically；　is　a　shortage　of　evidence。　since　the　dawn　of　time；several　billion　human　（or　humanlike）　beings　have　lived；　each　contributing　a　little　geneticvariability　to　the　total　human　stock。　out　of　this　vast　number；　the　whole　of　our　understandingof　human　prehistory　is　based　on　the　remains；　often　exceedingly　fragmentary；　of　perhaps　fivethousand　individuals。　“you　could　fit　it　all　into　the　back　of　a　pickup　truck　if　you　didn’t　mind2humans　are　put　in　the　lamely　homimdae。　its　members；　traditionally　called　hominids；　include　any　creatures（including　extinct　ones）　that　are　more　closely　related　to　us　than　to　any　surviving　chimpanzees。　the　apes；meanwhile；　are　lumped　together　in　a　family　called　pongidae。　many　authorities　believe　that　chimps；　gorillas；　andorangutans　should　also　be　included　in　this　family；　with　humans　and　chimps　in　a　subfamily　called　homininae。
the　upshot　is　that　the　creatures　traditionally　called　hominids　bee；　under　this　arrangement；　hominins。　（leakeyand　others　insist　on　that　designation。）　hominoidea　is　the　name　of　the　aue　sunerfamily　which　includes　us。
how　much　you　jumbled　everything　up；”　ian　tattersall；　the　bearded　and　friendly　curator　ofanthropology　at　the　american　museum　of　natural　history　in　new　york；　replied　when　i　askedhim　the　size　of　the　total　world　archive　of　hominid　and　early　human　bones。
the　shortage　wouldn’t　be　so　bad　if　the　bones　were　distributed　evenly　through　time　andspace；　but　of　course　they　are　not。　they　appear　randomly；　often　in　the　most　tantalizing　fashion。
homo　erectus　walked　the　earth　for　well　over　a　million　years　and　inhabited　territory　from　theatlantic　edge　of　europe　to　the　pacific　side　of　china；　yet　if　you　brought　back　to　life　everyhomo　erectus　individual　whose　existence　we　can　vouch　for；　they　wouldn’t　fill　a　school　bus。
homo　habilis　consists　of　even　less：　just　two　partial　skeletons　and　a　number　of　isolated　limbbones。　something　as　short…lived　as　our　own　civilization　would　almost　certainly　not　be　knownfrom　the　fossil　record　at　all。
“in　europe；”　tattersall　offers　by　way　of　illustration；　“you’ve　got　hominid　skulls　in　georgiadated　to　about　1。7　million　years　ago；　but　then　you　have　a　gap　of　almost　a　million　years　beforethe　next　remains　turn　up　in　spain；　right　on　the　other　side　of　the　continent；　and　then　you’ve　gotanother　300；000…year　gap　before　you　get　a　homo　heidelbergensis　in　germany—and　none　ofthem　looks　terribly　much　like　any　of　the　others。”　he　smiled。　“it’s　from　these　kinds　offragmentary　pieces　that　you’re　trying　to　work　out　the　histories　of　entire　species。　it’s　quite　atall　order。　we　really　have　very　little　idea　of　the　relationships　between　many　ancient　species—which　led　to　us　and　which　were　evolutionary　dead　ends。　some　probably　don’t　deserve　to　beregarded　as　separate　species　at　all。”
it　is　the　patchiness　of　the　record　that　makes　each　new　find　look　so　sudden　and　distinct　fromall　the　others。　if　we　had　tens　of　thousands　of　skeletons　distributed　at　regular　intervals　throughthe　historical　record；　there　would　be　appreciably　more　degrees　of　shading。　whole　new　speciesdon’t　emerge　instantaneously；　as　the　fossil　record　implies；　but　gradually　out　of　other；　existingspecies。　the　closer　you　go　back　to　a　point　of　divergence；　the　closer　the　similarities　are；　so　thatit　bees　exceedingly　difficult；　and　sometimes　impossible；　to　distinguish　a　late　homoerectus　from　an　early　homo　sapiens；　since　it　is　likely　to　be　both　and　neither。　similardisagreements　can　often　arise　over　questions　of　identification　from　fragmentary　remains—deciding；　for　instance；　whether　a　particular　bone　represents　a　female　australopithecus　boiseior　a　male　homo　habilis。
with　so　little　to　be　certain　about；　scientists　often　have　to　make　assumptions　based　on　otherobjects　found　nearby；　and　these　may　be　little　more　than　valiant　guesses。　as　alan　walker　andpat　shipman　have　drily　observed；　if　you　correlate　tool　discovery　with　the　species　of　creaturemost　often　found　nearby；　you　would　have　to　conclude　that　early　hand　tools　were　mostly　madeby　antelopes。
perhaps　nothing　better　typifies　the　confusion　than　the　fragmentary　bundle　of　contradictionsthat　was　homo　habilis。　simply　put；　habilis　bones　make　no　sense。　when　arranged　in　sequence；they　show　males　and　females　evolving　at　different　rates　and　in　different　directions—the　malesbeing　less　apelike　and　more　human　with　time；　while　females　from　the　same　period　appearto　be　moving　away　from　humanness　toward　greater　apeness。　some　authorities　don’t　believehabilis　is　a　valid　category　at　all。　tattersall　and　his　colleague　jeffrey　schwartz　dismiss　it　as　amere　“wastebasket　species”—one　into　which　unrelated　fossils　“could　be　conveniently　swept。”
even　those　who　see　habilis　as　an　independent　species　don’t　agree　on　whether　it　is　of　the　samegenus　as　us　or　is　from　a　side　branch　that　never　came　to　anything。
finally；　but　perhaps　above　all；　human　nature　is　a　factor　in　all　this。　scientists　have　a　naturaltendency　to　interpret　finds　in　the