首页
登录
职称英语
An Australian research group may ease humanity’s collective conscience over
An Australian research group may ease humanity’s collective conscience over
游客
2024-09-15
44
管理
问题
An Australian research group may ease humanity’s collective conscience over a spate of prehistoric extinctions on the southern continent. The die-off, they say, was not the rapacious work of newly arrived humans, but was due rather to changing climate.
Australia’s large prehistoric animals, called megafauna, were as bizarre as anything that lives there today. King of them all was the marsupial lion, a 130-kilogram meat-eater who lived alongside giant kangaroos, huge lizards called goannas, and Diprotodon, which resembled a three-tonne wombat.
After the arrival of humans on the continent, at least 45, 000 years ago, these weird and wonderful creatures began to die out. Experts blamed the colonizers, arguing that they launched a hunting ’ blitzkrieg’ that wiped out the megafauna(巨型动物)within a few generations.
But the animals may have survived for a lot longer than people thought, argues Judith Field of the University of Sydney, who has analyzed fossil remains. Her excavations seem to show that man and beast lived side by side for as long as 15, 000 years.
She suspects that as Australia approached the most recent ice age, the growing cold and aridity turned much of the continent into a place where these large animals simply could not survive. Although man probably did hunt the large animals, the fact that they survived for so long argues against the blitzkrieg(闪电战)model, she adds.
Field and her colleagues collected animal bones from a ten-metre-deep section of earth at Cuddie Springs, New South Wales. They focused on bones from four layers: two with evidence of human settlement, such as stone tools, and two deeper ones with no evidence of tools.
They dated the bones by measuring the amounts of radioactive elements, such as uranium and thorium, that remained in the bones. They found that the various animal carcasses in each level would indeed have lived cheek by jowl with humans as recently as 30, 000 years ago. The team report their research in Proceedings of the National Academy of Sciences.
Proponents of the blitzkrieg model had previously argued that the dating of the Cuddie Springs material was not certain, but Field says their research clears up the matter. Well-preserved bones at other sites have been very hard to find, probably because they are too dry, whereas Cuddie Springs is the site of an old lake bed.
A second group, reporting in the journal Memoirs of the Queensland Museum, has also unveiled evidence that climate change may have killed off many of Australia’s animals. By looking at smaller animal bones from the Darling Downs in Queensland, they show that their disappearance seems to have coincided with increasing dryness.
But the matter is not settled yet, particularly as the timing of humans’ first foray into Australia has still not been agreed. Fossil evidence from Lake Mungo in New South Wales suggests that they may have arrived 60, 000 years ago. And it is possible that they hastened the megafauna’s demise by burning habitats to make way for primitive agriculture.
Field remains convinced, however, that it was climate that drove the animals to their death. "The arid zone grew to encompass 70% of the continent by 30, 000 years ago, " she says. "There would have been very few opportunities once it got dryer." [br] What do the experts collect to do the experiments at Cuddie Springs?
选项
A、Animal tracks.
B、Animal pictures.
C、Animal bones.
D、Animal fossils.
答案
C
解析
细节题。从第六段首句Field and her colleagues collected animal bones from a ten-metre-deep section of earth at Cuddie Springs,…可知答案为[C]。
转载请注明原文地址:http://tihaiku.com/zcyy/3759289.html
相关试题推荐
[A]excessively[I]degradation[B]collectively[J]neutralize[C]positiv
[A]excessively[I]degradation[B]collectively[J]neutralize[C]positiv
[A]excessively[I]degradation[B]collectively[J]neutralize[C]positiv
[A]excessively[I]degradation[B]collectively[J]neutralize[C]positiv
[A]excessively[I]degradation[B]collectively[J]neutralize[C]positiv
______aresearchstudent,Iwouldatleastmastertwoforeignlanguages.A、Should
ProfessorJohnsonissaid______somesignificantadvanceinhisresearchinthep
ShouldFinancialSupportOnlyBeProvidedforScientificResearch?Thef
AcademicResearchandProjectDesignI.Introduction—【T1】i
AcademicResearchandProjectDesignI.Introduction—【T1】i
随机试题
JacklosthisJoblastweek.Itwasdifficultforhimtofindanother【C1】___
[originaltext]W:Ihaveaveryimportantthingtoaskyou.DoyouspeakFrench?
Perfectcertaintybelongsonlytothegods;therestofushavetomakedowith
[originaltext]M:Ipassedbythestreetinfrontofourcollegeyesterday.Doy
敞口水箱的满水试验和密闭水箱(罐)的水压试验必须符合设计与本规范的规定。检验方法
下列说法与资料相符的是:A.沿海港口合计吞吐量2008年1月的同比增长额高于
对新参加电气工作人员、实习人员、临时参加劳动人员和外单位派来支援的人员有什么要求
我国税收收入占国民生产总值比重表 1985~1998年期间,我国国内生产总
有271位游客欲乘大、小两种客车旅游,已知大客车有37个座位,小客车有20个座位
下列导致现有设备贬值的情形中,属于设备有形磨损的有()。A.设备连续使用导致零
最新回复
(
0
)