# Kelp - 科目：雅思听力真题（Part 4） - 考频：中频 - 最近考试：2007.2.3 - 题目数：10 - 来源页：https://www.yaquan.site/paper/80289832-50f4-40e8-91e7-1f5c7f83e185（在线机考练习与音频请访问该页面） - 数据更新：2026-10-29 ## 题目原文 00:00:00,240 Thirty-one to forty. 00:00:04,700 The next lectures in this current series will deal with various aspects of marine ecology, or how the various forms of sea life relate to each other. And today, I'm going to talk about the fortunes of a type of seaweed called kelp. 00:00:23,620 In the past few years, scientists have been coming up with formulae or equations for calculating the effects on marine life of natural events such as hurricanes, or those due to humans, such as pollution or fishing. And the more information they can feed into these equations, the better. Now, some of the predictions that were made initially turned out to be highly inaccurate, and it was suspected that this was due to insufficient historical data being available. So when a team of international scientists recently set out to reevaluate the state of various coastal ecosystems from Australia to Alaska, they were concerned to increase reliability by collecting as much of this kind of data as possible. And when the extra dimension was included, the findings of the team were startling. 00:01:24,140 Their studies demonstrated that there has always been a complex interaction between animals and plants living in our seas, between the top predators and the grazers and grassy plains of the ocean floors. We now know much more about what happens when humans intervene in this system. 00:01:47,620 We know that playing with nature's ecosystems is extremely risky. You remove just one species of animal, and it can have an impact on the whole system, often in an entirely unpredictable way. 00:02:08,160 Let's look first of all at some of the findings relating to the kelp forests of Alaska. 00:02:14,980 From the ocean shore, these look rather uninspiring, just piles of seaweed apparently floating on the surface. But when you dive down into them, they're incredible. They are these great jungles of greenery stretching as much as a hundred feet from the seabed all the way to the surface. And they're one of the most productive ecosystems in the world. They are full of wildlife, and they're important nursery grounds for many of the fish we eat. 00:02:48,280 In Alaska, a team of scientists carefully pieced together the chain of events behind the fluctuating fortunes of the kelp forests. The main characters in the story were sea urchins, which feed on kelp, and sea otters, which prey on the sea urchins. Sea otters were abundant in that system for three to five million years. And then somewhere between two and a half to four thousand years ago, when early people first occupied that region, the otter population began to decline, and it probably declined as a consequence of overhunting. However, the declines were relatively small in scale at that time and localized, probably around village sites. 00:03:38,340 So early humans had hunted the otters. This left more sea urchins to graze the kelp forests, clearing great patches of it. For thousands of years, this occurred only near native settlements until the Europeans arrived. In the mid seventeen hundreds, the Alaskan waters were discovered by the Bering expedition, and that set off the North Pacific fur trade. 00:04:04,880 And as a consequence of that, otter populations were rapidly depleted to very low levels across the whole region. And that, in turn, caused an explosion of the sea urchin population and thus a collapse of the kelp forests. 00:04:23,760 So when humans wiped out the top predator, grazers took over and overgrazed the kelp forests until they were devastated. 00:04:33,980 Then in the early nineteen hundreds, before the Alaskan sea otters were completely wiped out, they became a protected species. 00:04:43,900 And as the otter population built up again, sea urchin numbers declined. So for much of the twentieth century, kelp forests recovered and began to flourish again, although they were nothing like the vibrant ecosystem they had once been. 00:05:01,500 In some ways, it was like English woodlands, where large predators like wolves and bears have been replaced by voles and shrews. 00:05:11,800 But unfortunately, the story doesn't end there. The roller coaster ride of the kelp ecosystem was far from over. 00:05:21,220 In the late twentieth century, the unlucky sea otters began to decline again because this time they were being eaten by killer whales. 00:05:32,300 So scientists set out to find why killer whales had suddenly changed their diets, and they have come to a tentative conclusion. The killer whales had been eating young sea lions and harbor seals, and perhaps northern fur seals. But when these animals declined, they switched to eating otters. This was an unprecedented event, one that scientists believe had never happened before in history. And by about nineteen ninety-six, otter populations had been devastated. So as a result of this, the kelp forests can be expected to decline again since the sea urchin numbers are no longer controlled by the otters. And so the cycle continues. 00:06:27,020 On the other side of the continent, in Maine... 00:06:33,380 That is the end of part four. 00:06:36,140 You now have forty-five seconds to check your answers to part four. ## 题目与答案 ### 31. 31 Recent discoveries concerning marine life have been more accurate than earlier ones, because scientists have 31 Recent discoveries concerning marine life have been more accurate than earlier ones, because scientists have - studied a wide geographical area - included more information about the past - worked as a team on the project **答案**：included more information about the past 原文定位：Now, some of the predictions that were made initially turned out to be highly inaccurate, and it was suspected that this was due to insufficient historical data being available. So when a team of international scientists recently set out to reevaluate;they were concerned to increase reliability by collecting as much of this kind of data as possible 同义替换：「earlier」↔「initial」；「included more information about the past」↔「insufficient historical data」 ### 32. 32 An international study has shed light on 32 An international study has shed light on - the effects of human activity on marine life - the extinction of a particular marine animal - the benefits of a marine conservation project **答案**：the effects of human activity on marine life 原文定位：So when a team of international scientists recently set out to reevaluate the state of various coastal ecosystems from Australia to Alaska;Their studies demonstrated that there has always been a complex interaction between animals and plants living in our seas;We now know much more about what happens when humans intervene in this system 同义替换：「shed light on」↔「We now know much more about」；「the effects of human activity on marine life」↔「what happens when humans intervene in this system」 ### 33. Fluctuating fortunes of the Alaskan kelp forests 2,500-4,000 years ago otter number began to fall in areas around 33_____ ↓ Fluctuating fortunes of the Alaskan kelp forests 2,500-4,000 years ago otter number began to fall in areas around 33_____ ↓ - Alaska - fell - flourished - fur trade - kelp forests - rose **答案**：villages 原文定位：And then somewhere between two and a half to four thousand years ago, when early people first occupied that region, the otter population began to decline, and it probably declined as a consequence of overhunting. However, the declines were relatively small in scale at that time and localized, probably around village sites 同义替换：「otter number began to fall」↔「the otter population began to decline」 ### 34. sea urchins reduced kelp in places ↓ mid 1700s start of 34_____ sea urchins reduced kelp in places ↓ mid 1700s start of 34_____ - Alaska - fell - flourished - fur trade - kelp forests - rose **答案**：fur trade 原文定位：In the mid seventeen hundreds, the Alaskan waters were discovered by the Bering expedition, and that set off the North Pacific fur trade 同义替换：「start of」↔「set off」 ### 35. ↓ otter numbers 35_____ ↓ otter numbers 35_____ - Alaska - fell - flourished - fur trade - kelp forests - rose **答案**：fell 原文定位：And as a consequence of that, otter populations were rapidly depleted to very low levels across the whole region 同义替换：「numbers」↔「populations」 ### 36. ↓ sea urchin numbers 36_____ ↓ sea urchin numbers 36_____ - Alaska - fell - flourished - fur trade - kelp forests - rose **答案**：rose 原文定位：And as a consequence of that, otter populations were rapidly depleted to very low levels across the whole region. And that, in turn, caused an explosion of the sea urchin population and thus a collapse of the kelp forests 同义替换：「rose」↔「explosion」 ### 37. ↓ 37_____ devastated ↓ 37_____ devastated - Alaska - fell - flourished - fur trade - kelp forests - rose **答案**：kelp forests 原文定位：And as a consequence of that, otter populations were rapidly depleted to very low levels across the whole region. And that, in turn, caused an explosion of the sea urchin population and thus a collapse of the kelp forests. So when humans wiped out the top predator, grazers took over and overgrazed the kelp forests until they were devastated ### 38. early 1900s 38_____ acquired protection ↓ sea urchin numbers declined ↓ kelp forests flourished early 1900s 38_____ acquired protection ↓ sea urchin numbers declined ↓ kelp forests flourished - Alaska - fell - flourished - fur trade - kelp forests - rose **答案**：sea otters 原文定位：Then in the early nineteen hundreds, before the Alaskan sea otters were completely wiped out, they became a protected species 同义替换：「acquired protection」↔「became a protected species」 ### 39. In recent times,39_____ have started feeding on sea otters. In recent times,39_____ have started feeding on sea otters. **答案**：killer whales 原文定位：In the late twentieth century, the unlucky sea otters began to decline again because this time they were being eaten by killer whales 同义替换：「feed on」↔「being eaten by」 ### 40. In the near future, kelp forests are predicted to 40_____ . In the near future, kelp forests are predicted to 40_____ . **答案**：decline 原文定位：So as a result of this, the kelp forests can be expected to decline again since the sea urchin numbers are no longer controlled by the otters 同义替换：「In the near future」↔「can be expected to」 --- 以上内容由鸭圈雅思真题库（www.yaquan.site）提供，收录近期雅思考试真题回忆，支持在线机考模式免费练习。