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
58
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. "
The volcanoes theory cannot convince everyone because______.
选项
A、there are gaps in the volcanoes theory and the time line is not clearly defined
B、modern humans had not yet spread into the heart of Europe
C、modern humans were not as experienced as Neanderthals in coping with natural calamity
D、the population of Neanderthals was much larger than that of modern humans
答案
A
解析
文章第七段中提及火山理论也有缺陷,即火山理论中尚有空白之处,时间线也不明确,这是火山理论不能令所有人信服的原因。
转载请注明原文地址:https://kaotiyun.com/show/EWiO777K
0
专业英语八级
相关试题推荐
Outinthestreetatlast,themanstoppedrunningandlookedbackatthestepsofthegallery.Thewomanwasnotfollowinghim.
SomehearteningstatisticswerereportedlastyearbytheJournaloftheNationalCancerInstitute:themortalityrateforbreas
Asimplifiedlanguagederivedfromtwoormorelanguagesiscalledapidgin.Itisacontactlanguagedevelopedandusedbypeop
WheredidthePilgrimFathersbuildtheirfirstsettlementinAmerica?
HowmanyyearsdostudentshavetostudyatcommunitycollegeintheUnitedStates?
Anextremeexampleofafederalsystemistheoneadoptedinthe1970sinYugoslavia,knownasworkers’self-management.Primary
A、thehistorichatredbetweenSunniandShiiteMuslimsB、therearesectarianterroristsamongbothSunniandShiiteMuslimsC、Su
Twohalf-brothers,SirHumphreyGilbertandSirWalterRaleigh,werethefirstEnglishmentoundertakeseriousventuresinAmeri
Nowadaysmoreandmorepeoplespendtheirleisuretimetraveling,havingsightseeingofthebeautifulspotsandplacesofhistor
TheDesertedVillagewaswrittenby_____,theoutstandingrepresentativeofthesentimentalistschool.
随机试题
证明下列不等式:
蓝氏贾第鞭毛虫杜氏利什曼原虫
谷胱甘肽分子结构的特点是有一肽键为氨基酸的α-氨基与相邻氨基酸的()位羧基以肽键相连。
心室纤颤最常见的病因是
质量为m的两小球带等量同号电荷q,现用长为l的细线悬挂于空中O点,如图7-1所示,当小球平衡时,测得它们之间的水平距离为x,此时绳子的张力为()。
带有绿色标志的通道适用于携运物品在数量上和价值上都超过免税限额的旅客。()
下列不属于期货公司风险监管措施的是()。
甲公司为上市公司。2014年度至2016年度,甲公司及其子公司发生的有关交易或事项如下:(1)2014年1月1日,甲公司以银行存款30500万元从非关联方购入乙公司60%的股权,能够主导乙公司相关活动并获得可变回报。购买日乙公司可辨认净资产的公允价值为
2004年3月15日,洪海市雅居房地产公司合法取得位于市区的能够进行商品房开发#3地块的土地使用权,2006年3月,该#3地块上开发出“海滨雅居”进行销售,甲花费60万元在“海滨雅居”购得一套住房。入住使用后,甲发现房屋由于设计错误存在严重的结构缺陷。在与
请用不超过200字的篇幅,概括出给定资料所反映的主要问题。要求:概括全面,层次分明,条理清楚,表述简洁。根据给定资料,自选角度,自拟题目,写一篇新农村建设规划方面的文章。要求:中心明确、内容充实、条理清楚、联系实际,行文流畅。1200字
最新回复
(
0
)