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
2024-10-17
29
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] 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://tihaiku.com/zcyy/3805421.html
相关试题推荐
Theintroductionofnon-native"exotic"speciesisnowseenasamajorthre
Thehumanspeciescameintobeingatthetimeofthegreatestbiologicaldiv
Thehumanspeciescameintobeingatthetimeofthegreatestbiologicaldiv
Thehumanspeciescameintobeingatthetimeofthegreatestbiologicaldiv
Thehumanspeciescameintobeingatthetimeofthegreatestbiologicaldiv
Beethovenestablishedhimselfasthegreatestcomposer[br][originaltext]B
Beethovenestablishedhimselfasthegreatestcomposer[originaltext]Beethov
ThatLouiseJohannesisbelievedbymanycriticstobethegreatesttwentiet
ThatLouiseJohannesisbelievedbymanycriticstobethegreatesttwentiet
ThatLouiseJohannesisbelievedbymanycriticstobethegreatesttwentiet
随机试题
[originaltext]Shouldwecomplaintothemanager?(A)No,let’sjustwaitfora
InwhatfieldmighttheexampleofHelenKellerbefit?[originaltext]Oneof
在简单随机抽样中,某一个个体被抽到的可能性()。A.与第几次抽样有关,第一次抽
舞蹈是一种表演艺术,使用身体来完成各种优雅或高难度的动作,一般有音乐伴奏,以有节
为研究某地30~49岁健康男子的血清白蛋白平均水平,随机抽查了其中的132名男子
患者经前乳房胀痛或乳头痒痛,痛甚不可触衣,胸闷痰多,食少纳呆,平素带下量多,色白
1995年,甲按房改标准价800元/m2,购买了本单位A小区的一套60m2的住房
急性脓胸常用的排脓方法正确的有 A.开放引流B.反复胸腔穿刺 C.经胸腔镜
以下指标可以用来评价渠道畅通性的有()。A.商品周转速度 B.货款回收速度
男性患者,64岁,反复咳嗽、咯痰,痰中带血2周。体温38.3℃.WBC12×10
最新回复
(
0
)