首页
登录
职称英语
The human species came into being at the time of the greatest biological div
The human species came into being at the time of the greatest biological div
游客
2024-09-24
49
管理
问题
The human species came into being at the time of the greatest biological diversity in the history of the Earth. Today, as human populations expand and alter the natural environment, they are reducing biological diversity to its lowest level. The ultimate consequences of this biological reduction are beyond calculation, but they are certain to be harmful. That, in essence, is the biodiversity crisis.
The history of global diversity can be summarized as follows: after the initial flowering of multicellular animals, there was a swift rise in the number of species in early Paleozoic times (between 600 and 430 million years ago), then plate-alike stagnation for the remaining 200 million years of the Paleozoic era, and finally a slow but steady climb through the Mesozoic and Cenozoic eras to diversity’s all-time high. This history suggests that biological diversity was hard won and a long time in coming. Furthermore, this pattern of increase was set back by five massive extinction episodes. The most recent of these, during the Cretaceous period, is by far the most famous, because it ended the age of the dinosaurs, giving hegemony to the mammals, thus ultimately making possible the dominance of the human species over the Earth. But the Cretaceous crisis was minor compared with the Permian extinctions 240 million years ago, during which between 77 and 96 percent of marine animal species perished. It took five million years, well into Mesozoic times, for species diversity to begin a significant recovery.
Within the past 10,000 years biological diversity has entered a wholly new era. Human activity has had a devastating effect on species diversity, and the rate of human-induced extinctions is accelerating. Half of the bird species of Polynesia have been eliminated through hunting and the destruction of native forests. The list of such biogeographic disasters is extensive.
Because every species is unique and irreplaceable, the loss of biodiversity is the most profound process of environmental change. Its consequences are also the least predictable because the value of the Earth’s species remains largely unstudied and unappreciated; unlike material and cultural wealth, which we understand because they are the substance of our everyday lives, biological wealth is usually taken for granted. This is a serious strategic error, one that will be increasingly regretted as time passes. [br] The consequences from the loss of biodiversity are difficult to predict because
选项
A、we haven’t fully studied and understood the value of the Earth’s species.
B、there have been so many disasters that we don’t know the extent of each.
C、environmental changes usually take place over a long period of time.
D、no one really knows what the original state of affairs was on the Earth.
答案
A
解析
定位于文章最后一段第二句“它(生物多样性的减少)的后果也是最难预测的,这是因为地球物种的价值大部分都没有被研究过…”,由此可知答案为[A]。
转载请注明原文地址:https://tihaiku.com/zcyy/3771583.html
相关试题推荐
Thehumanspeciescameintobeingatthetimeofthegreatestbiologicaldiv
Thehumanspeciescameintobeingatthetimeofthegreatestbiologicaldiv
Theintroductionofnon-native"exotic"speciesisnowseenasamajorthre
Theintroductionofnon-native"exotic"speciesisnowseenasamajorthre
Beethovenestablishedhimselfasthegreatestcomposer[br][originaltext]B
Beethovenestablishedhimselfasthegreatestcomposer[br][originaltext]B
Thelistofcandidatesforgreatestmenofthe20thcenturyisasshortasi
Thelistofcandidatesforgreatestmenofthe20thcenturyisasshortasi
Thelistofcandidatesforgreatestmenofthe20thcenturyisasshortasi
Thelistofcandidatesforgreatestmenofthe20thcenturyisasshortasi
随机试题
Gavin’sapartmentislocatedonthe[br][originaltext]Diane:Goodmorning,Dia
ClimateClimateisthelong-termpatternofweatherina【T1】______area.
ThespeakersaretalkingaboutNorwoodUniversityonthephone.[br][originalt
某铁路局2018年完成的总运量为500亿换算吨公里,运输总支出为60亿元,其中固
女,48岁。月经频发,经量增多,妇科检查:子宫大小正常,双侧附件未见异常,服用雄
【教学过程】 (一)导入新课 幻灯片出示图片创设情境,提问学生:为什么父母反对孩子吃方便面与零食?引发学生思考,让学生自由发言,从而引出课题。 (二
共用题干 HowtoGetAlongWellWithYourBo
某男性患者,25岁。牙冠切1/3横断,近中髓角暴露24小时,无松动,口内余牙无异
银行承兑汇票的承兑银行,应当按照票面金额向出票人收取()的手续费。A:千分之一
一男性,某省厅干部,平时不嗜烟酒,生活规律;但性情急躁,易激动,工作认真,争强好
最新回复
(
0
)