Pleistocene Rewilding托福聽力原文翻譯及問題答案

Pleistocene Rewilding托福聽力原文翻譯及問題答案

一、Pleistocene Rewilding托福聽力原文：

NARRATOR:Listen to part of a lecture in a zoology class.

FEMALE PROFESSOR:A mass extinction as when numerous species become extinct over a very short time period.Short,geologically speaking that is,like when the dinosaurs died out 65 million years ago.And the fossil record,it indicates that in all the time that animals have inhabited Earth,there have been five great mass extinctions,dinosaurs being the most recent.In each of the others up to half of all land animals and up to 95 percent of marine species disappeared.

Well,today,we're witnessing a sixth mass extinction,but unlike the others,the current loss of biodiversity can be traced to human activity.Since the Stone Age,humans have been eliminating species and altering ecosystems with astounding speed?countless species have disappeared due to overhunting,habitat destruction and habitat fragmentation,pollution,and other unnatural,human causes.So,as a way of repairing some of that damage,a group of conservation biologists has proposed an ambitious—some might say a radical—plan involving large vertebrates,or megafauna.Megafauna include elephants,wild horses,big cats,camels—large animals. Uh,actually,the proposal focuses on a particular subset of megafauna—the kind that lived during the Pleistocene epoch.

OK.The Pleistocene epoch,most commonly known as the Ice Age,stretched from 1.8 million to 11,500 years ago. In the Americas,most megafauna began disappearing by the end of the Pleistocene.

So here is the biologists?idea: Take a select group of animals—megafauna from places like Africa and Asia,and introduce them into other ecosystems similar to their current homes,beginning in the western United States.They call their plan Pleistocene rewilding.

Now,the advocates of Pleistocene rewilding cite two main goals. One is to help prevent the extinction of some endangered megafauna by providing new refuges,new habitats for them.The other's to restore some of the evolutionary and ecological potential that's been lost in North America. Wh-what do I mean by"restore evolutionary potential"?Well,as you know,the evolution of any species is largely influenced by its interactions with other species.

So,during the Pleistocene epoch...let's take the now-extinct American cheetah,for instance.We believe it played a pivotal role in the evolution of the pronghorn antelope—the antelope's amazing speed,to be exact,because natural selection would favor those antelope that could outrun a cheetah.When the American cheetahs disappeared,their influence on the evolution of pronghorn,and presumably on other prey animals,stopped.So,it's conceivable that the pronghorn antelope would've continued to evolve,get faster maybe,if the cheetahs were still around.That't what't meant by"evolutionary potential." Importing African cheetahs to the western United States could,in theory,put the pronghorn back onto its,uh,natural evolutionary trajectory,according to these biologists.

Another example is the interaction of megafauna with local flora,in particular,plants that rely on animals to disperse their seeds.Like Pleistocene rewilding could spark the re-emergence of large seeded American plants,such as the maclura tree.Many types of maclura used to grow in North American,buy today,just one variety remains and it is found in only two states.

In the distant past,large herbivores like mastodons dispersed maclura seeds,each the size of an orange in their droppings.Well,there aren't any mastodons left,but there are elephants,which descended from mastodons.Introduce elephants into that ecosystem and they might disperse those large maclura seeds,like their ancestors did.Get the idea?Restoring some of the former balance to the ecosystem?But as I alluded to earlier,Pleistocene rewilding is extremely controversial.A big worry is that these transplanted megafauna might devastate plants and animals that are native to the western United States.In the years since the Pleistocene epoch,native species have adapted to the changing environmental there,plants,smaller animals,they have been evolving without megafauna for millennia.Also,animal species that went extinct 11,000 years ago,uh,some are quite different genetically from their modern-day counterparts,like elephants don't have thick coats like their mastodon ancestors do when they graze the prairies of the America West during the Ice Age.Granted,the climate today is not as cold as it was in the Pleistocene.

But winters on the prairie can still get pretty harsh today.And there are many more considerations.Well,you see how complex this is.If you think about it though,the core problem with this sixth mass extinction is human interference.Pleistocene rewilding is based on good intentions,but you know,it probably would just be more of the same thing.

二、Pleistocene Rewilding托福聽力中文翻譯：

旁白：在動物學(xué)課上聽一節(jié)課的一部分。

女教授：大規(guī)模滅絕，如許多物種在很短的時間內(nèi)滅絕。簡而言之，從地質(zhì)學(xué)角度來說，就像6500萬年前恐龍滅絕的時候?；涗洷砻?，在動物居住地球的所有時間里，有五次大規(guī)模滅絕，恐龍是最新的。在其他每個國家，多達一半的陸地動物和95%的海洋物種消失了。

今天，我們目睹了第六次大滅絕，但與其他物種不同的是，目前生物多樣性的喪失可以追溯到人類活動。自石器時代以來，人類一直在以驚人的速度消滅物種和改變生態(tài)系統(tǒng)？由于過度狩獵、棲息地破壞和棲息地破碎、污染以及其他非自然的人類原因，無數(shù)物種已經(jīng)消失。因此，作為修復(fù)部分破壞的一種方式，一群保護生物學(xué)家提出了一項雄心勃勃的計劃，有些人可能會說這是一項涉及大型脊椎動物或巨型動物群的激進計劃。大型動物包括大象、野馬、大型貓科動物、駱駝和大型動物；呃，事實上，該提案關(guān)注的是大型動物群的一個特定子集，即生活在更新世時期的那種動物。

好啊更新世，最廣為人知的冰期，從180萬年前一直延續(xù)到11500年前；在美洲，大多數(shù)大型動物群在更新世末開始消失。

生物學(xué)家來了？想法：；從非洲和亞洲等地挑選一組大型動物群，從美國西部開始，將它們引入與其當(dāng)前家園類似的其他生態(tài)系統(tǒng)。他們把他們的計劃稱為更新世的重繞。

現(xiàn)在，更新世重熔的倡導(dǎo)者列舉了兩個主要目標(biāo)；一是為一些瀕危巨型動物提供新的避難所和棲息地，以防止它們滅絕。另一個是恢復(fù)北美失去的一些進化和生態(tài)潛力；我說的“恢復(fù)進化潛力”是什么意思？正如你所知，任何物種的進化在很大程度上都受到其與其他物種相互作用的影響。

所以，在更新世時期。。。以現(xiàn)已滅絕的美國獵豹為例。我們相信它在叉角羚的進化過程中起到了關(guān)鍵作用，確切地說，叉角羚的驚人速度，因為自然選擇會青睞那些跑得比獵豹快的羚羊。當(dāng)美洲獵豹消失后，它們對叉角羚進化的影響，可能對其他捕食動物的影響就停止了。所以，可以想象，如果獵豹還在的話，叉角羚羊會繼續(xù)進化，可能會更快。這不是“進化潛力”的意思&nbsp；根據(jù)這些生物學(xué)家的說法，從理論上講，將非洲獵豹進口到美國西部可以使叉角羚回到其自然進化軌道上。

另一個例子是大型動物群與當(dāng)?shù)刂参锶旱南嗷プ饔?，特別是依賴動物傳播種子的植物。像更新世一樣，重繞可能會引發(fā)大型種子美國植物的重新出現(xiàn)，例如馬克魯拉樹。過去在北美種植的許多種類的麥盧拉，今天購買，只剩下一種，只有兩個州有。

在遙遠的過去，像乳齒象這樣的大型食草動物散布著麥盧拉種子，每個種子的糞便中都有一個橘子大小。嗯，已經(jīng)沒有乳齒象了，但有大象，它們是乳齒象的后裔。將大象引入生態(tài)系統(tǒng)，它們可能會像它們的祖先一樣傳播那些大的麥盧拉種子。明白了嗎？恢復(fù)生態(tài)系統(tǒng)以前的一些平衡？但正如我早些時候提到的，更新世的重繞是非常有爭議的。令人擔(dān)憂的是，這些移植的巨型動物群可能會破壞美國西部的動植物。在更新世以來的幾年里，本地物種已經(jīng)適應(yīng)了那里不斷變化的環(huán)境，植物和小型動物，它們在沒有大型動物的情況下進化了數(shù)千年。此外，11000年前滅絕的動物物種，呃，有些在基因上與現(xiàn)代同類有很大不同，比如大象不像他們的乳齒象祖先在冰河時期放牧美國西部大草原時那樣有厚厚的皮毛。誠然，今天的氣候不像更新世時那么冷。

但大草原上的冬天今天仍然會變得相當(dāng)嚴(yán)酷。還有更多的考慮。你看這有多復(fù)雜。如果你仔細(xì)想想，第六次大滅絕的核心問題是人類的干擾。更新世的重繞是基于良好的意圖，但你知道，這可能只是更多的相同的事情。

三、Pleistocene Rewilding托福聽力問題：

Q1:1.What is the lecture mainly about?

A.A proposal to identify all the animals that became extinct dining the Pleistocene epoch

B.A strategy for reintroducing native plants to an ecosystem

C.A process for identifying alternative habitats for large animals

D.A proposal to re-create features of ecosystems of the Pleistocene epoch

Q2:2.According to the professor,what are the two main goals of Pleistocene rewilding?[Click on 2 answers.]

A.To restore some evolutionary processes that ended during the Pleistocene epoch

B.To help prevent the extinction of certain species of mega fauna

C.To increase populations of native animal species in the western United States

D.To create a living laboratory where animal interactions can be observed

Q3:3.According to the professor,how did the American cheetah influence the pronghorn antelope during the Pleistocene epoch?

A.The cheetah prevented the antelope’s population from growing too large.

B.The cheetah was a factor in the development of the antelope’s speed.

C.The cheetah dispersed the seeds of plants that the antelope needed to survive.

D.The cheetah caused the antelope to migrate out of the western United States.

Q4:4.What point does the professor make when she discusses the maclura tree?

A.The feeding habits of large animals could help revive some diminishing plant species.

B.The climate has changed in North America since the Pleistocene epoch.

C.Mass extinctions of animals are generally preceded by mass extinctions of plants.

D.The maclura tree has changed very little since the Ice Age.

Q5:5.Why does the professor say that plants and small animals have continued to evolve since the Pleistocene?

A.To indicate why the western United States is well suited for Pleistocene rewilding

B.To suggest a way to balance an ecosystem using Pleistocene rewilding

C.To identify a potential problem with the Pleistocene rewilding concept

D.To explain how the idea for Pleistocene rewilding came about

Q6:6.What does the professor mean when she says this:

A.Pleistocene rewilding has been tried before without success.

B.Pleistocene rewilding should be tried with just a few species.

C.Pleistocene rewilding has already been thoroughly researched.

D.Pleistocene rewilding is another form of human interference.

四、Pleistocene Rewilding托福聽力答案：

A1:正確答案：D

A2:正確答案：AB

A3:正確答案：B

A4:正確答案：A

A5:正確答案：C

A6:正確答案：D

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