首页
登录
职称英语
Over a century ago, Alfred Russell Wallace wrote that "we live in a zoologic
Over a century ago, Alfred Russell Wallace wrote that "we live in a zoologic
游客
2024-05-04
2
管理
问题
Over a century ago, Alfred Russell Wallace wrote that "we live in a zoologically poor world, from which all the hugest, fiercest and strangest forms have recently disappeared. " Researchers seeking to explain this " marvelous fact", as Wallace called it, fall into two camps, one invoking global climatic change and the other human hunting as the cause.
Over the past few decades, the debate has become
deadlocked, in part because most researchers have focused their attention on the Americas and northern Eurasia, where the extinction of the huge, fierce, and strange creatures, such as mammoths, and giant sloths(大树懒), occurred between 12, 500 and about 11, 000 years ago. This was a time of rapid climatic change, but it was also when humans first arrived in these regions, making it difficult to discern causality. Australia provides the only separate, continent-sized natural laboratory in which dramatic Quaternary extinctions occurred. It is thus of exceptional importance as a testing ground for extinction theories, but until now problems with dating have limited its potential. Miller and some people have now documented the extinction of the gigantic Australian bird and so have broken new ground in dating huge creatures extinction in Australia. At the same time, these authors have broken the current deadlock in the great huge creature extinction debate.
It has long been appreciated that the intensity of Quaternary extinctions varied greatly around the world. In the oceans, Africa, and Southeast Asia, they were nonexistent or mild. Europe experienced moderate extinction rates, whereas the Americas, Australia, Madagascar, and many Oceanic islands suffered dramatic extinctions. North America lost 73% of all forms weighing more than 44 kg, but Australia suffered the most severely of all the continents, losing every terrestrial vertebrate(脊椎动物)species larger than a human, as well as many smaller mammals, reptiles, and flightless birds, the latter down to about a kilogram in weight. In all, about 60 vertebrate species were lost, including bizarre marsupials(有袋类动物)that resembled giant sloths, kangaroos, and a terrestrial horned tortoise that approached the size of a Volkswagen Beetle car. Establishing just when this bizarre array of creatures last trod Australia’s outback has been an intricate business, with many false leads and sites that are difficult to interpret.
For decades, it was believed that the huge creatures survived until close to the time of the glacial maximum, some 20, 000 years ago, when temperatures were up to 9t cooler than at present and the continent was extremely arid. Conditions were so extreme that trees virtually disappeared from the inland, and 40% of Australia was transformed into a vast active dune field. [br] In the last paragraph, the author seems to be more agreeable to the idea that______ caused the extinction of huge creatures in Australia.
选项
答案
global climatic change
解析
从文中最后一段得知,澳大利亚在冰河极盛期时气候发生了巨大变化,这导致了陆地很大一部分变成了沙丘活动的荒野,故看出作者倾向于将大型动物的灭亡归因于气候的变化。
转载请注明原文地址:https://tihaiku.com/zcyy/3583234.html
相关试题推荐
Anightoutattheoperatoseeanadaptationofanobscure17th-centuryEng
Anightoutattheoperatoseeanadaptationofanobscure17th-centuryEng
Anightoutattheoperatoseeanadaptationofanobscure17th-centuryEng
Overacenturyago,AlfredRussellWallacewrotethat"weliveinazoologic
Overacenturyago,AlfredRussellWallacewrotethat"weliveinazoologic
Overacenturyago,AlfredRussellWallacewrotethat"weliveinazoologic
Livingstandardshavesoaredduringthe21stcentury,andeconomistsexpect
Livingstandardshavesoaredduringthe21stcentury,andeconomistsexpect
Livingstandardshavesoaredduringthe21stcentury,andeconomistsexpect
Livingstandardshavesoaredduringthe21stcentury,andeconomistsexpect
随机试题
亚洲人民创造了辉煌的文明成果。下列不属于亚洲文明成果的是()。A、《源氏物语》
财务管理的内容按资金运动过程可分为()。A.筹资管理 B.投资管理 C.营
张先生前往太平洋的某小岛旅游,手表时间仍显示北京时间。 该地所在的时区是()
相机抉择的财政政策调节总需求时所采取的财政措施有: A.变动支出水平 B.变
A.中成药 B.中药饮片 C.果味制剂 D.蛋白类制品在《基本医疗保险药品
关于“适应行为量表”,不正确的是A.适应行为与智力水平有较大关联 B.属于心理
研究一种疾病的严重程度时用( )。A.引入率 B.续发率 C.死亡率 D
2017年3月1日,甲公司聘请魏某为公司技术部门经理,双方在劳动合同中
220kV线路(见图5-17)K点发生两相接地短路。电源、线路阻抗标么值已在图中
已知同第1题。
最新回复
(
0
)