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
The human species came into being at the time of the greatest biological diversity in the history of the Earth. Today, as human
The human species came into being at the time of the greatest biological diversity in the history of the Earth. Today, as human
admin
2015-06-27
96
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.
All of the following contribute to the extinction of species EXCEPT
选项
A、hunting.
B、pollution.
C、deforestation.
D、the growth of human populations.
答案
B
解析
由第三段第三句“在波利尼西亚,有一半的鸟类由于人类捕猎或者当地森林被破坏而消失的”可排除[A]和[C];而根据第一段第二句“人类人口的不断增长以及对自然环境的改变,使物种数量降低到最低水平”可排除[D],因此答案为[B]。
转载请注明原文地址:https://kaotiyun.com/show/ZHXK777K
0
专业英语四级
相关试题推荐
Whatisthespeakermainlytalkingabout?
WhichofthefollowingareNOTthefirstpeopletoreceivetheswinefluvaccinations?
Humanity’sprimaleffortstosystematizetheconceptsofsize,shapes,andnumberareusuallyregardedastheearliestmathemati
Thelocalgovernmenthasto______thetaxschemebecauseofthestrongopposition.
Ofallthegoalsoftheeducationreformmovement,noneismoredifficultthandevelopinganobjectivemethodtoassessteachers
Anewdirection,resultingfromchangingvaluesandlifestyles,istheincreaseinpart-timeorjob-sharedwork.【C1】______nu
"Congratulations,Mr.Cooper,it’sagirl."Fatherhoodisgoingtohaveadifferentmeaningand【31】adifferentresponsefro
Whoneedsapublisher?BobYoung,CEOofprint-on-demandserviceLulu,com,saysthatthepublishingand【C1】______ofbooksonlin
Itistimeformetosee______dinner.
Thereceptionwasattendedby______membersofthelocalcommunity.
随机试题
创伤病人伴肝功能不全,进行肠内营养时,应注意调整()。
帕金森病药物治疗原则不包含
财政机关对甲有限责任公司(以下简称甲公司)20×2年度财务工作进行检查,但甲公司领导以“财务部门负责人出差”为由予以拒绝,后经多方协调,财政机关对该公司进行了检查,检查时,发现如下问题:(1)2月15日,公司从外地购买了一批货物,收到发票后,经办人员王某
学校作为法人最重要和最应该具备的条件是()。
我国的中央银行是:
儿童画没有原始艺术的那些历史负载,但在形式体验上有许多相似之处。儿童有一种未被扭曲的直觉,充满好奇心和新鲜感,能够将自己感兴趣的特征强烈地表现出来。儿童凭感性作画,直取主要印象,还有那无拘元束的想象力。早期的儿童是自我中心主义者,儿童毫不顾忌地表现自己的感
若执行下面程序时从键盘上输入5,main(){intx;scanf("%d",&x);if(x++>5)printf("%d\n",x);elseprintf("%d\n",x--);
下列关于二叉树的叙述中,正确的是()。
在考生文件夹下打开EXCEL.XLSX文件:选取“学号”列(A2:A10)和“总成绩”列(E2:E10)数据区域的内容建立“簇状棱锥图”,图表标题为“成绩统计图”,不显示图例,设置数据系列格式为纯色填充(紫色,强调文字颜色4,深色25%),将图插入到表
Whensome19th-century.NewYorkerssaid"Harlem",theymeantalmostallofManhattanaboveEighty-sixthStreet.Towardtheend
最新回复
(
0
)