11.Today,many species of animals and plants are endangered.This means they are in danger of becoming extinct and living on only in the pages of history books.The famous dodo is a classic example of a creature that became extinct.A flightless bird that lived on the island of Mauritius,it was discovered by sailors in 1598but was hunted to extinction by 1681.
Hunting has caused the Bengal tiger and the African elephant to be endangered today but habitat destruction can also lead to extinction.This is equally true for plants.Animals and plants disappear for other reasons too,but the main cause is often a disruption(打乱,破坏) in the natural food chain,whether due to hunting,habitat destruction,or even the introduction of alien species.
The natural food chain is the cycle that governs the existence of all life on this planet.It is a carefully balanced cycle and any imbalance that occurs can cause knock-on effects that have serious consequences.At the beginning of the natural food chain are plants which turn sunlight into energy and draw nutrients from the earth.Plants are called producers.
After the producers come the consumers.There are three tiers of consumers.First are creatures such as plant-eating animals,fish and insects which feed off the producers.These animals that only eat plants are called herbivores.The second tier of consumers are carnivores-animals that live off other animals.The third tier of consumers eats both other animals and plants.These consumers,including most humans,are called omnivores.
After animals and plants die,they become food for other smaller creatures,such as bacteria and some plants,such as fungi.As they feed,these creatures turn the dead bodies back into gases and minerals which are again food for the producers at the beginning of the food chain.And so the cycle continues.
All of nature is connected and governed by hundreds of these delicate food chains and if a single plant in the chain cannot survive,then the insects that live off the plant start to die and the animals that eat the insects also start to die.
When a food chain is disrupted,the consequences can be extremely serious.One estimate suggests that for each plant species that is lost,up to 30animals and insects may also die out.One wonders how many species were affected by the extinction of the dodo?
Humans can have disastrous effects on food chains.We've already mentioned hunting but now let's look at travel.When people first started to explore the world they took plant and animal species from their home countries and introduced them wherever they went.They didn't realize that by introducing alien species they were disrupting the natural food chains of the areas they discovered.Although there are strict rules in place today controlling the import and export of alien species,some places are still fighting the effects of aliens introduced hundreds of years ago.
For example,Gough Island in the South Atlantic Ocean is a breeding ground for albatrosses that have been nesting there for centuries.But in the 19th century,mice from passing ships were brought to the island.Being a species alien to the island,they had no natural predators and have now grown to such a size that they are attacking and killing albatross chicks.If they are allowed to continue,they will wipe out the albatross population.
With import laws and people's rising awareness of how humans affect the natural environment,hopefully we can learn to fit better into the natural food chains that govern our world.Otherwise we need to accept that the loss of any more plants and animals could eventually mean our own extinction.
62.What do the first two paragraphs mainly tell us?D
A.Hunting and habitat destruction lead to extinction.
B.Many species of animals and plants are endangered.
C.Plants and animals become extinct for the same reasons.
D.The main cause of extinction is often a disruption in the natural food chain.
63.Which of the following sentence is TRUE according to the passage?C
A.Strict rules alone can remove the bad effects of alien species.
B.Plants,herbivores and carnivores are the three tiers of consumers.
C.If a bird becomes extinct,the relevant food chain will be disrupted.
D.Animals and plants become extinct because alien species are imported.
64.By mentioning the mice in Gough Island,the author intends to highlightD.
A.mice worldwide are growing all the time
B.being aliens,they had no natural predators
C.some places are still fighting the effects of aliens
D.traveling can have disastrous effects on food chains
65.What is the best title of the passage?D
A.Survival of the fittest.
B.Endangered animals and plants.
C.How to protect the natural environment.
D.The link between food chains and extinction.
分析 作者通过对于多多鸟、信天翁的案例介绍、剖析,说明了食物链和物种灭绝之间的关系.
解答 62.D,细节理解题.根据文章第二段Animals and plants disappear for other reasons too,but the main cause is often a disruption in the natural food chain,whether due to hunting,habitat destruction,oreven the introduction of alien species.可知,动植物消失的主要原因是对于天然食物链的破坏,无论是由于捕猎,栖息地破坏,或者甚至是外星物种的进入.可知D正确.
63.C,推理判断题.根据文章第六段的One estimate suggests that for each plant species that is lost,upto 30 animals and insects may also die out.One wonders how many species were affected by the extinction of the dodo?可知:每一种物种的消失,都会导致30种动物和昆虫的灭亡.人们琢磨,由于多多鸟的灭亡有多少物种会受到影响.由此可知C 是正确的.
64.D,推理判断题.根据文章第八段的We've already mentioned hunting but now let's look at travel.和第九段But in the 19th century,mice from passing ships were brought to the island.可知旅行对于物种的影响也很大,老鼠的侵入导致了信天翁的数量急剧减少,破坏了当地的食物链.
65.D,标题归纳题,作者通过列举多多鸟和信天翁的事实,主要说明食物链和物种灭绝之间的关系,故答案为D.
点评 解答任务型阅读理解题,首先对原文材料迅速浏览,掌握全文的主旨大意.因为阅读理解题一般没有标题,所以,速读全文,抓住中心主旨很有必要,在速读的过程中,应尽可能多地捕获信息材料.其次,细读题材,各个击破.掌握全文的大意之后,细细阅读每篇材料后的问题,弄清每题要求后,带着问题,再回到原文中去寻找、捕获有关信息.最后,要善于抓住每段的主题句,阅读时,要有较强的针对性.对于捕获到的信息,要做认真分析,仔细推敲,理解透彻,只有这样,针对题目要求,才能做到稳、准.