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, and even in remote parts of Australia, frogs are losing the ecological battle for survival, and biologists are at a loss to explain their demise. Are amphibians simply oversensitive to changes in the ecosystem? Could it be that their rapid decline in numbers is signaling some coming environmental disaster for us all? This frightening scenario is in part the consequence of a dramatic increase over the last quarter century in the development of once natural areas of wet marshland; home not only to frogs but to all manner of wildlife. However, as yet, there are no obvious reasons why certain frog species are disappearing from rainforests in Australia that have barely been touched by human hand. 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 , 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 species of frog that, at far as is known, has become extinct, is the platypus frog. Like the well-known Australian mammal it was named after, it exhibited some very strange behaviour; instead of giving birth to tadpoles in the water, it raised its young within its stomach. The baby frogs were actually born from out of their mothers mouth. Discovered in 1981, less than ten years later the frog had completely vanished from the crystal clear waters of Booloumba Creek near Queenslands Sunshine Coast. Unfortunately, this freak of nature is not the only frog species to have been lost in Australia. Since the 1970s, no less than eight others have suffered the same fate.
One theory 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.
TRUE/FALSE/NOT GIVEN
1.Frogs are disappearing only from city areas.
2.Frogs and toads are usually poisonous.
3.Biologists are unable to explain why frogs are dying.
4.The frogs natural habitat is becoming more and more developed.
5.Attempts are being made to halt the development of wet marshland.
6.Frogs are important in the ecosystem because they control pests.
7.The platypus frog became extinct by 1991.
8.Frogs usually give birth to their young in an underwater nest.
9.Eight frog species have become extinct so far in Australia.
10.There is convincing evidence that the ozone layer is being depleted.
11.It is a fact that frogs breeding cycles are upset by worldwide in creases in temperature.
Answer Keys1.F 2.F 3.T 4.T 5.NG 6.T 7.T 8.NG 9.F 10.T 11.F
2015年成人学位英语练习:挑错真题解析(12)
2016年成人英语英汉互译造成解题困难的因素
2015年成人学位英语汉译英步骤
2016年成人学位英语英译汉习题及答案(二)
2015年成人学位英语阅读理解复习:迅读要点
2016年成人学位英语英译汉习题及答案(四)
2015年成人学位英语优秀作文范文100篇
2016年成人学位英语考试完形填空试题(六)
2015年成人学位英语练习:挑错真题解析(13)
2016年成人学位英语词汇辅导E字母开头(004)
2016年成人学位英语词汇辅导E字母开头(003)
2015年成人学位英语改错大纲要求及应试策略
2015年成人学位英语写作技巧
2015年成人学位英语写作范文:大学生考证热
2016年成人学位英语词汇辅导D字母开头(007)
肇庆学院2016年成人学位英语考试报名通知
2016学位英语词汇辅导C(字母开头)汇总
兰州理工大学2016年成人学位英语考试报名通知
2016年成人学位英语考试完形填空试题(四)
2016年学位英语阅读理解解题技巧之巧妙绕开生词
2016年成人学位英语词汇辅导C字母开头(013)
2016年成人学位英语英译汉习题及答案(三)
2015年成人学位英语写作主题句的写法及特征
2016年成人学位英语考试完形填空试题(五)
2016年成人学位英语考试完形填空试题(二)
2015年成人学位英语挑错答题对策
2016年成人学位英语英译汉精选试题(二)
2016年成人学位英语考试五步破解破解阅读理解
2016年成人学位英语考试完形填空试题(七)
2015年成人学位英语练习:挑错真题解析(14)
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |