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
When was the last time you saw a frog? Chances are, if you live in a city, you have not seen one for some time. Even in wet area
When was the last time you saw a frog? Chances are, if you live in a city, you have not seen one for some time. Even in wet area
admin
2011-01-05
55
问题
When was the last time you saw a frog? Chances are, if you live in a city, you have not seen one for some time. Even in wet areas once teeming with frogs and toads, it is becoming less and less easy to find those slimy, hopping and sometimes poisonous members of the animal kingdom. All over the world, even in remote jungles on the far side of the globe, frogs are losing the ecological battle for survival, and biologists are at a loss to explain their demise. Are amphibians
simply over-sensitive to changes in the ecosystem? Could their rapid decline in numbers be signalling some coming environmental disaster for us all?
This frightening scenario is in part the consequence of a dramatic increase over the last quarter of a century in the development of once natural areas of wet marshland; home not only to frogs but to all manner of wildlife. Yet, there are no obvious reasons why certain frog species are disappearing from rainforests in the Southern Hemisphere which are barely touched by human hands. The mystery is unsettling to say the least, for it is known that amphibian species are extremely sensitive to environmental variations in temperature and moisture levels. The danger is that planet Earth might not only lose a vital link in the ecological food chain (frogs keep populations of otherwise pestilent insects at manageable levels) , but we might be increasing our output of air pollutants to levels that may have already become irreversible. Frogs could be inadvertently warning us of a catastrophe.
An example of a bizarre occurrence regarding a species of frog dates from the summer of 1995 , when "an explosion” of multi-coloured frogs of the species Rana klepton esculenta occurred in the Netherlands. Normally these frogs are brown and greenish-brown, but some unknown contributory factor is turning these frogs yellow and / or orange. Nonetheless, so far, the unusual bi- and even tri-coloured frogs are functioning similarly to their normal-skinned contemporaries. It is thought that frogs with lighter coloured skins might be more likely to survive in an increasingly warm climate due to global warming.
One theory put forward to explain extinct amphibian species that seems to fit the facts concerns the depletion of the ozone layer, a well-documented phenomenon which has led to a sharp increase in ultraviolet radiation levels. The ozone layer is meant to shield the Earth from UV rays, but increased radiation may be having a greater effect upon frog populations than previously believed. Another theory is that worldwide temperature increases are upsetting the breeding cycles of frogs.
Some unknown contributory factor is turning frogs yellow and / or orange in the______.
选项
答案
Netherlands
解析
(答案见第三段。Netherlands荷兰。)
转载请注明原文地址:https://kaotiyun.com/show/iJVK777K
本试题收录于:
C类竞赛(非英语专业本科)题库大学生英语竞赛(NECCS)分类
0
C类竞赛(非英语专业本科)
大学生英语竞赛(NECCS)
相关试题推荐
(1)AnextremecoldspellmightbeunwelcometomuchoftheNorthernHemisphere,butitiswarmlywelcomedbyonegroup—theoi
(1)Sometimesyouhavetotravelveryfartogainperspectiveonthingsinyourowncountry.Recently,ItaughtaUNICEF-sponsor
(1)Themanyhourschildrenspendindoorsplayingcomputergamesorwatchingtelevisionmaybetoblameforaresurgenceofrick
Therehavebeenanumberofstudiesonsmokingamongtheyoung.【T1】________,ithasbeenfoundthatmanyofthechildrenliving
A、Ituseslotsofgas.B、Itistooexpensivetobuy.C、Itistypicalforroadtrips.D、Itcanholdtenpeople.A原文中,男士说他旅行开的是典型的
A、Becauseshewasbusywithherstudy.B、Becauseshewasillinbed.C、Becauseshedidn’tknowtherewassuchatour.D、Because
A、Enjoyingalcoholicdrinks.B、Goingtochurch.C、Openingpresents.D、Holdingpublicevents.D原文中,女士询问男士圣诞节是否有放烟花或其他的公共活动,男士回答说没
Thegovernment________apublicdebateonthefuturedirectionoftheofficialsportspolicy.
(1)BecauseImarriedaphotographer,oncewehadchildren,ourholidaycardsofcoursebecamevehiclesfortheircutenessandh
Mostcandidateswillprobably________catastropheiftheytrytowriteperfectlyineverywaytheexaminersaskedfor.
随机试题
提示病情危重的异常姿态是
甲超市与乙食品厂签订买卖合同。约定:乙食品厂应在农历八月十五日前两周,向甲超市交付各色月饼1万盒。依照我国《合同法》有关规定,下列陈述错误的是:()
依照《中华人民共和国行政处罚法》的规定,城市规划行政处罚程序执行的是()。
【背景资料】某住宅楼工程,场地占地面积约10000m2,建筑面积约14000m2,地下两层,地上16层,层高2.8m,檐口高47m,结构设计为筏板基础。剪力墙结构,施工总承包单位为外地企业,在本项目所在地设有分公司。本工程项目经理组织编
简述生命周期理论与持久收入理论之间的异同。
王老板买了很多房子,根据房产税法律制度的有关规定,在()地方买入的房屋不属于房产税纳税范围。
政府不作为的行为也会产生政治风险,下列选项中属于这类风险产生的直接表现是()。
第一个提出要使教育学成为科学,并把教育理论建立在伦理学和心理学基础之上的教育家是___________,其代表作是___________。
定义:①写景抒情诗:歌咏山水名胜、描写自然景色的抒情诗歌。古代有些诗人由于不满现实,常寄情于山水,通过描绘江湖风光、自然风景来寄寓自己的思想感情。这类诗常将要抒发的情感寄寓在描写的景物之中,这就是人们常说的寓情于景,其风格清新自然。②咏物言志诗:诗人对
若在(一∞,+∞)上连续,则a=___________.
最新回复
(
0
)