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（打亂，破壞） 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 作者通過對于多多鳥、信天翁的案例介紹、剖析，說明了食物鏈和物種滅絕之間的關系．
解答 62．D，細節理解題．根據文章第二段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，動植物消失的主要原因是對于天然食物鏈的破壞，無論是由于捕獵，棲息地破壞，或者甚至是外星物種的進入．可知D正確．
63．C，推理判斷題．根據文章第六段的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：每一種物種的消失，都會導致30種動物和昆蟲的滅亡．人們琢磨，由于多多鳥的滅亡有多少物種會受到影響．由此可知C 是正確的．
64．D，推理判斷題．根據文章第八段的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．可知旅行對于物種的影響也很大，老鼠的侵入導致了信天翁的數量急劇減少，破壞了當地的食物鏈．
65．D，標題歸納題，作者通過列舉多多鳥和信天翁的事實，主要說明食物鏈和物種滅絕之間的關系，故答案為D．
點評 解答任務型閱讀理解題，首先對原文材料迅速瀏覽，掌握全文的主旨大意．因為閱讀理解題一般沒有標題，所以，速讀全文，抓住中心主旨很有必要，在速讀的過程中，應盡可能多地捕獲信息材料．其次，細讀題材，各個擊破．掌握全文的大意之后，細細閱讀每篇材料后的問題，弄清每題要求后，帶著問題，再回到原文中去尋找、捕獲有關信息．最后，要善于抓住每段的主題句，閱讀時，要有較強的針對性．對于捕獲到的信息，要做認真分析，仔細推敲，理解透徹，只有這樣，針對題目要求，才能做到穩、準．
