首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Catastrophic volcanic eruptions in Europe may have culled Neanderthals to the point where they couldn’t bounce back, according t
Catastrophic volcanic eruptions in Europe may have culled Neanderthals to the point where they couldn’t bounce back, according t
admin
2012-04-23
56
问题
Catastrophic volcanic eruptions in Europe may have culled Neanderthals to the point where they couldn’t bounce back, according to a controversial new theory. Modern humans, though, squeaked by, thanks to fallback populations in Africa and Asia, researchers say.
About 40,000 years ago in what we now call Italy and the Caucasus Mountains, which straddle Europe and Asia, several volcanoes erupted in quick succession, according to a new study to be published in the October issue of the journal Current Anthropology. It’s likely the eruptions reduced or wiped out local bands of Neanderthals and indirectly affected farther-flung populations, the team concluded after analyzing pollen and ash from the affected area. The researchers examined sediments layer from around 40,000 years ago in Russia’s Mezmaiskaya Cave and found that the more volcanic ash a layer had, the less plant pollen it contained.
"We tested all the layers for this volcanic ash signature. The most volcanic-ash-rich layer"—likely corresponding to the so-called Campanian Ignimbrite eruption, which occurred near Naples—"had no (tree) pollen and very little pollen from other types of plants," said study team member Naomi Cleghorn. "It’s just a sterile layer." The loss of plants would have led to a decline in plant-eating mammals, which in turn would have affected the Neanderthals, who hunted large mammals for food. "This idea of an environmental cause for the Neanderthals’ demise has been out in the literature. What we’re trying to do is point out a specific mechanism," said Cleghorn, an anthropologist at the University of Texas, Arlington.
Other theories propose that modern humans played a vital role in the fall of the Neanderthals, either through competition, warfare, or interbreeding. If the volcanoes theory is correct, the Neanderthals’ end was much more tragic: dying slowly in a cold and desolate landscape bereft of food sources. "It’s hard to say what it would have been like to be the last few groups out there, seeing other groups less and less over the years," Cleghorn said.
The Neanderthals were a hardy species that lived through multiple ice ages and would have been familiar with volcanoes and other natural calamities. But the eruptions 40,000 years ago were unlike anything Neanderthals had faced before, Cleghorn and company say. For one thing, all the volcanoes apparently erupted around the same time. And one of those blasts, the Campanian Ignimbrite, is thought to have been the most powerful eruption in Europe in the last 200,000 years. "It’s much easier to adapt to something that’s happening over a couple of generations," Cleghorn said. "You can move around, you can find other places to live, and your population can rebound. " "This is not that kind of event," she said, "This is unique. "
There may also have been small bands of Homo sapiens living in Europe at the time, Cleghorn said. They too would have been affected by the eruptions. But modern humans likely avoided extinction because they had larger populations in Africa and Asia, she said, while most Neanderthals were in Europe around this time. "With their small population groups, Neanderthals did not really have a great source population," Cleghorn said. "They didn’t really have the numbers and the density" to rebuild their populations after the eruptions.
The researchers acknowledge that there are gaps in the volcanoes theory. For instance, the time line needs to be better defined—did the volcanic eruptions occur in a period of months, years, or decades? "At this point, it’s impossible to pin down a reliable date" for the eruptions, Cleghorn said. "We can’t say that this eruption happened 50 years before the next eruption. We just don’t have that kind of resolution." It’s also unknown exactly how long it took the Neanderthals to die out—or how long after the eruptions modern humans began settling Europe in force, she said.
Anthropologist John Hoffecker, though, suggests that modern humans had already begun crowding out Neanderthals in Europe long before the eruptions in question. Judging from discoveries of modern-human artifacts in former Neanderthal strongholds, Hoffecker said, "Neanderthals were clearly in trouble well before 40,000 years ago, because modern humans were occupying certain places, such as Italy, where Neanderthals had been present. So something clearly had gone wrong there. " Perhaps, he added, the volcanic eruptions just dealt the final blow. "I’m not entirely convinced that’s the case either," said Hoffecker, of the University of Colorado. "But at least that’s a plausible scenario that’s consistent with the chronology. " Study co-author Cleghorn counters that the modern human populations living in Europe 40,000 years ago were small and isolated, and only after the Neanderthals were gone did Homo sapiens populations explode. "If modern humans were making any forays into European Neanderthal territory prior to this, they were doing it only on the very margins," Cleghorn said. "What was keeping them from moving very quickly into the heart of Europe? We think Neanderthals were still holding their own and might have held out for much longer, if it hadn’t been for the devastating impact of these eruptions. "
What does "bounce back" mean in the first paragraph?
选项
A、leap suddenly
B、recover from a terrible situation
C、refuse to accept
D、come back after being refused
答案
B
解析
本题考查考生对上下文的推断能力。上文提到欧洲“灾难性的火…喷发”,后面紧跟“to the point where”,我们可以推断出该处的意思是恢复。
转载请注明原文地址:https://kaotiyun.com/show/BWiO777K
0
专业英语八级
相关试题推荐
A、ParisB、NewYorkC、MoscowD、LondonB
A、AgoodmemoryisveryimportantinstudyingEnglish.B、Thecomplexmovementofhumanbrains.C、Humanmemoryandhowtouseit.
HenryDavidThoreau’swork,______hasalwaysbeenregardedasatmasterpieceofNewEnglandTranscendentalism.
Britain’seastmidlandswereoncethepictureofEnglishcountryside,alivewithflocks,shepherds,skylarksandbuttercupsthe
Whoisthecreatorandagreatmasterofthehistoricalnovel?
Thebizarreanticsofsleepwalkershavepuzzledpolice,perplexedscientists,andfascinatedwritersforcenturies.Thereisan
A、School.B、Cleanhouse.C、TheEnvironmentalProtectionAgency’sheadquarters.D、Noneoftheabove.D
A、Ithaslostitsprimaryoxygensources.B、Ithaslostitsbackupoxygensources.C、Ithaslostboththeprimaryandthebackup
PrimaryColorsThemoviePrimaryColorsisaboutagrey-haired,gravel-voiced,doughnut-lovinggovernorfromaSouthernAmeric
A、wasdefeatedbyhissocialistopponentB、waselectedasthenewPresidentofFranceC、hadmorethan7096ofthevoteD、announ
随机试题
Forthispart,youareallowed30minutestowritealetteronthefollowingquestion.Youshouldwriteatleast120wordsbut
求。
阅读《往事》中的一段文字,回答下列小题:她住在灯塔的岛上,海霞是她的扇旗,海鸟是她的侍从;夜晚她曳着白衣蓝裳,头上插着新月的梳子,胸前挂着明星的璎珞;翩翩地飞行于海波之上……大风的时候,她驾着风车,狂飙疾转的在怒涛上驱走……下雨的时候,……她落泪了
A.左下6B.右上5C.右上1D.右上ⅣE.左上Ⅲ按部位记录法右上第一乳磨牙
在计算应纳税所得额时,不得扣除的支出有()。
其他情况:原材料:期初无库存原材料;本期购入3500公斤,单价1.6元/公斤,耗用3250公斤。在产品:原材料为一次投入,期初在产品存货40件,完工程度50%;本月投产450件,完工入库430件;期末在产品60件,完工程度50%。产成品:期初产成品存货30
事件A=“随机抽取5件产品,至少有4件合格品”与事件B=“随机抽取5件产品,恰有1件不合格品”的关系是()。
"Twitter,likeFacebook,isapopularwayformanypeopletolearnaboutnews,andsomeTwitterusershaveuseditasawayto
采用PKCS算法,网络中N个用户之间进行加密通信,需要的密钥个数是()。
联接运算是将两个或两个以上的关系根据联接条件生成一个【】。
最新回复
(
0
)