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
Britain’s east midlands were once the picture of English countryside, alive with flocks, shepherds, skylarks and buttercups—the
Britain’s east midlands were once the picture of English countryside, alive with flocks, shepherds, skylarks and buttercups—the
admin
2011-01-08
54
问题
Britain’s east midlands were once the picture of English countryside, alive with flocks, shepherds, skylarks and buttercups—the stuff of fairytales. In 1941 George Marsh left school at the age of 14 to work as a herdsman in Nottinghamshire, the East Midlands countryside his parents and grandparents farmed. He recalls skylarks nesting in cereal fields, which when accidentally disturbed would fly singing into the sky. But in his lifetime, Marsh has seen the color and diversity of his native land fade. Farmers used to grow about a ton of wheat per acre; now they grow four tons. Pesticides have killed off the insects upon which skylarks fed, and year-round harvesting has driven the birds from their winter nests. Skylarks are now rare. "Farmers kill anything that affects production," says Marsh. "Agriculture is too efficient. "
Anecdotal evidence of a looming crisis in biodiversity is now being reinforced by science. In their comprehensive surveys of plants, butterflies and birds over the past 20 to 40 years in Britain, ecologists Jeremy Thomas and Carly Stevens found significant population declines in a third of all native species. Butterflies are the furthest along—71 percent of Britain’s 58 species are shrinking in number, and some, like the large blue and tortoiseshell, are already extinct. In Britain’s grasslands, a key habitat, 20 percent of all animal, plant and insect species are on the path to extinction. There’s hardly a corner of the country’s ecology that isn’t affected by this downward spiral.
The problem would be bad enough if it were merely local, but it’s not : because Britain’s temperate ecology is similar to that in so many other parts of the world, it’s the best microcosm scientists have been able to study in detail. Scientists have sounded alarms about species’ extinction in the past, but always specific to a particular animal or place—whales in the 1980s or the Amazonian rain forests in the 1990s. This time, though, the implications are much wider. The Amazon is a "biodiversity hot spot" with a unique ecology. But in Britain, "the main drivers of change are the same processes responsible for species’ declines worldwide, "says Thomas. The findings, published in the journal Science, provide the first clear evidence that the world is in the throes of a massive extinction. Thomas and Stevens argue that we are facing a loss of 65 to 95 percent of the world’s species, on the scale of an ice age or the meteorite that may have wiped out the dinosaurs 65 million years ago.
If so, this would be only the sixth time such devastation had occurred in the past 600 million years. The other five were associated with one-off events like the ice ages, a volcanic eruption or a meteor. This time, ecosystems are dying a thousand deaths—from overfishing and the razing of the rain forests, but also from advances in agriculture. The British study, for instance, finds that one of the biggest problems is nitrogen pollution. Nitrogen is released when fossil fuels burn in cars and power plants—but also when ecologically rich heath-lands are plowed and fertilizers are spread. Nitrogen-rich fertilizers fuel the growth of tall grasses, which in turn overshadow and kill off delicate flowers like harebells and eyebrights.
Even seemingly innocuous practices are responsible for vast ecological damage. When British farmers stopped feeding horses and cattle with hay and switched to silage, a kind of preserved short grass, they eliminated a favorite nesting spot of corncrakes, birds known for their raspy nightly mating calls; corncrake populations have fallen 76 percent in the past 20 years. The depressing list goes on and on.
Many of these practices are being repeated throughout the world, in one form or another, which is why scientists believe that the British study has global implications. Wildlife is getting blander. "We don’t know which species are essential to the web of life so we’re taking a massive risk by eliminating any of them," says David Wedin, professor of ecology at the University of Nebraska. Chances are we’ll be seeing the results of this experiment before too long.
According to David Wedin, the extinction of many species are caused by human beings,
选项
A、arrogance.
B、ignorance.
C、nonchalance.
D、blunder.
答案
B
解析
推断题。由题干中的David Wedin定位至末段。倒数第二句指出:We don’t know which species are essential to the web of life so we’re taking a massive risk by eliminating any of them,这说 明人们无法分辨哪种物种对我们来说是至关重要的,由于无知造成了许多物种灭绝的局面, 故[B]为答案。
转载请注明原文地址:https://kaotiyun.com/show/gCeO777K
0
专业英语八级
相关试题推荐
AftersomanyyearsofstudyingEnglish,youmaystillgetconfusedlikeyoufirstcomeherejustbecauseoftheslangthestude
ItispossibleforstudentstoobtainadvanceddegreesinEnglishwhileknowinglittleornothingabouttraditionalscholarlyme
Forwelloveracentury,onestreetinNewYorkCityhasbeenknownastheheartoftheAmericantheater.Thenameofthestreet
Ethnographyisthestudyofaparticularhumansocietyortheprocessofmakingsuchastudy.Contemporaryethnographyisbased
American’slifehasonceagainbeengreatlychangedbythenewageofscienceandtechnologysincetheSecondWorldWar.Everyth
Specializationcanbeseenasaresponsetotheproblemofanincreasingaccumulationofscientificknowledge.Bysplittingupt
Theold-agepaternalismofsouthernCanadiansoverEskimoshasdiedmoreslowlyintheruralvillageswhereEskimoshavebeenmo
A、EasternEuropeB、NorthernEuropeC、WesternEuropeD、SouthernEuropeA
WhichofthefollowingstatementsisnottheeffectofTheGreatDepressionstartedin1929?
随机试题
邓某经所在区工商局批准开了一家书店,一日当地一工商所人员丁某来到邓某的店里说:"有人举报称你经营淫秽书刊,现要对你罚款"。邓某再三解释也于事无补,无奈之下,当场交了1000元罚款,亦未收到罚单。事后,邓某向有关机关申请复议,丁某得知复议人员是自己的好友匡某
二氧化碳测定仪是以()为基础设计的,可检测出瓶装啤酒中瓶颈空气及二氧化碳含量。
失血性休克补充血容量是为了()。
某育肥猪群,部分猪出现消瘦、咳嗽、打喷嚏、腹式呼吸等症状,X线检查见肺部有云絮状阴影,剖检病死猪见肺心叶、尖叶上胰样病灶。治疗该病应选用的药物是
某被告不服一审法院驳回管辖异议的裁定提起上诉,在此期间,一审原告向一审法院提出撤诉申请。根据民事诉讼法的规定,正确的作法是()。
ARROW评级体系中风险评估的内容主要包括可能影响银行的外部风险。()
洗钱者通过金融机构洗钱的技巧包括()
求助者的社会接纳程度也可以看作是()。
一般资料:求助者,女性,42岁,已婚,大学文化程度,某公司业务经理。案例介绍:求助者父母的家在郊区,自己结婚后在市内购房生活,平时与父母、哥哥、姐姐的关系很融洽。因城市改造,求助者父母的房子被拆迁了,得到了两套房子和大笔拆迁款。求助者的父母自己住
因甲市某区阳光小区进行旧城改造,区政府作出《关于做好阳光小区旧城改造房屋拆迁补偿安置工作的通知》,王某等人对该通知不服,向区政府申请行政复议,要求撤销该通知。区政府作出《行政复议告知书》,告知王某等人向甲市政府申请复议。甲市政府作出《行政复议决定书》,认为
最新回复
(
0
)