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
2010-07-19
58
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," say’s 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何种生物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/melO777K
0
专业英语八级
相关试题推荐
Themiddleofthe18thcenturywaspredominatedbyanewlyrisingliteraryform,thatisthemodemEnglish______,whichgivesa
WhenGermanyinvadedPoland,BritainandFrancedeclaredwaronGermany.ThentheU.S【1】______indebate.Rooseveltaskedc
WhoweretheancestorsoftheEnglishandthefoundersofEngland?
WhatisthecauseoftheproblemthatpeoplelivingonpartsofthesouthcoastofEnglandface?Theerosionofthewhitecliff
PeoplelivingonpartsofthesouthcoastofEnglandfaceaseriousproblem.In1993,theownersofalargehotelandofseveral
HowmanypeoplediedintherecentconflictbetweenIraqipeopleandtheU.S.-ledcoalitiontroops?
HowmanypeoplediedintherecentconflictbetweenIraqipeopleandtheU.S.-ledcoalitiontroops?
A、Peopleofcomparativelyhigherlevels.B、Peopleconsistinglargelyofuniversitystudents,postgraduates,Englishworkers.C、T
BesidesFrenchwords,Englishalsoabsorbedasmanyas2,500wordsof_____intheMiddleEnglishperiod.
Thirty-twopeoplewatchedkittyGenovesebeingkilledrightbeneaththeirwindows.Shewastheirneighbor.Yetnoneofthe32he
随机试题
会计科目编号设计的作用有
简述制造业企业核算产品生产成本应遵循的要求。
销售净利率是()比率之一。
甲与乙系高中同学,毕业后一起到南方某城市打工,但发现南方钱并不好挣。某日,甲乙两人商量到某别墅区有钱人家里盗窃。然后两人就到该市郊区的别墅区,甲在门口望风。乙进门寻找财物,但发现保姆在里间做家务,此时,保姆将该房间在里面锁上。乙大怒,用匕首将该房间撬开,朝
(2010年)一平面简谐波在弹性媒质中传播时,某一时刻在传播方向上一质元恰好在负的最大位移处,则它的()。
沥青混凝土路面施工工艺要求中,对SMA和OGFC等嵌挤型混合料不宜小于集料公称最大粒径的()倍。
根据预算法律制度的规定,乡、民族乡、镇预算的调整方案应当提请本级人民代表大会审查和批准。()
一平行板电容器的两极板与一电压恒定的电源相连,极板水平放置,间距为d,一带电粒子P静止在电容器上部空间中。若在电容器中水平插入一厚度为d1(d1<d)的不带电的金属板N,在N全部插入电容器后(如图4所示),下列关于金属板所处位置与粒子加速度α的叙述正确的是
Fromherwordswerealizedthatshewasreallylookingforwardto______us.
Lookatthelistbelow.Forquestions6-10,decidewhichkindofservice(A-H)eachpersonontheoppositepageneeds.Foreachqu
最新回复
(
0
)