Gause's Hypothesis托福聽力原文翻譯及問題答案

Gause's Hypothesis托福聽力原文翻譯及問題答案

一、Gause's Hypothesis托福聽力原文：

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

FEMALE PROFESSOR:OK.Back in the 1930's,a biologist named G.F.Gause first proposed what's known as"Gause's hypothesis".

Gause said that whenever you've got two similar species competing for the exact same limited resources,one of them will have some sort of advantage,however slight that'll eventually enable this species to dominate and ultimately exclude the other one,even cause it to become extinct.That's why Gause's hypothesis came to be called"The competitive exclusion principle".Gause did some lab experiments like placing two Paramecium species in the same environment where they would have to compete for the same food.He found that,over time,one species was consistently able to drive out the other,to eliminate it from the habitat,just as his hypothesis predicted.Now,one of the early criticisms of Gause's hypothesis was that,"Sure,it works in simple lab experiments,where you have just two competing species in a controlled environment.But the hypothesis falls apart when applied to natural ecosystems where things are more complex."

Now it's true that in the real world,there are lots of examples that seem to contradict the hypothesis. For example,in the forests of New England,in the northeastern United States,there are some small songbirds called warblers.Yet,these five wobbler species all managed to coexist.—there is no dominance,no exclusion of one species by another....

How is this possible?

Well,turns out that one wobbler species feeds in the uppermost branches,while others favor the middle branches and others feed toward the bottom of the tree.Also,each wobbler species breeds at a different time of year.This way,the period of peak food requirement,when-when the birds are feeding their chicks,varies from one species to the next. 

FEMALE PROFESSOR:Yes,Mark.

MALE STUDENT:But does that really contradict Gause's hypothesis?Because,I mean,are those different wobbler species really competing for the same food?I don't think so.I think they're more like,you know,almost cooperating so that they don't have to compete.FEMALE PROFESSOR:Excellent!To the casual observer,the wobblers do seem to contradict Gause's hypothesis since they all live in the same place and eat the same types of insects.

But if you observe these birds more closely,the wobbler species are not really competing with one another for the exact same food at the exact same time.Mark,can you tell us what an ecological niche is?MALE STUDENT:The place where the plant or animal lives,you know,its habitat?FEMALE PROFESSOR:For example?MALE STUDENT:Uh,like the polar bear living in the Arctic,on the ice sheet. The Arctic is its niche,the habitat it's adapted to survive in.

FEMALE PROFESSOR:Okay.That's what most people think of....

But for biologists,the concept of a niche also includes the way an organism functions in its habitat,how it interacts with other plant and animal species,with the soil,the air,the water and so on.Okay,now let's put it all together:

if you have two similar species competing in the same niche,what's going to happen?Susan?FEMALE STUDENT:One will dominate the other and eventually eliminate it.FEMALE PROFESSOR:Okay.

So what could the weaker species do to improve its chances of survival?FEMALE STUDENT:Maybe just move to some other area,you know,away from the competitor?

FEMALE PROFESSOR:That's one possibility.But think of the scientific definition of a niche.Think about the wobblers.

Mark?MALE STUDENT:Maybe it could find some new way of functioning in its habitat so that it wouldn't have to compete with the dominant species.Keep the same habitat but not the exact same niche.FEMALE PROFESSOR:Yes,and there are many ways to do that.—the dominant species feeds in one part of the tree and you feed in another....

MALE STUDENT:If the dominant species needs lots of water,you develop the ability to survive on very little water?FEMALE PROFESSOR:You survive on what's left over.Water,food,nesting or breeding sites,...whatever.

二、Gause's Hypothesis托福聽力中文翻譯：

旁白：在生物課上聽一部分講座。

女教授：好吧。回到20世紀30年代，一位名叫G.F.高斯的生物學家首次提出了所謂的“高斯假說”。

高斯說，每當你有兩個相似的物種競爭相同的有限資源時，其中一個會有某種優(yōu)勢，無論多么微小，最終都會使這個物種占據(jù)主導地位，最終排斥另一個物種，甚至導致它滅絕。這就是為什么高斯的假設被稱為“競爭排斥原理”。高斯做了一些實驗室實驗，比如把兩種草履蟲放在同一個環(huán)境中，它們必須競爭相同的食物。他發(fā)現(xiàn)，隨著時間的推移，一個物種始終能夠?qū)⒘硪粋€物種趕出棲息地，將其從棲息地中消除，正如他的假設所預測的那樣。現(xiàn)在，對高斯假設的早期批評之一是，“當然，它在簡單的實驗室實驗中起作用，在受控環(huán)境中只有兩個競爭物種。但當應用于自然生態(tài)系統(tǒng)時，該假設會分崩離析，因為那里的情況更復雜?！?/p>

事實上，在現(xiàn)實世界中，有很多例子似乎與假設相矛盾&nbsp；例如，在美國東北部新英格蘭的森林中，有一些小型鳴鳥，叫做鶯。然而，這五種搖擺物種都設法共存-一個物種不存在優(yōu)勢，也不存在另一個物種排斥。。。。

這怎么可能？

事實證明，一種搖擺的物種在最上面的樹枝上覓食，而其他物種則喜歡中間的樹枝，其他物種則向樹的底部覓食。此外，每種搖擺動物在一年中的不同時間繁殖。這樣，鳥類喂食小雞時的食物需求高峰期因物種而異；

女教授：是的，馬克。

男學生：但這真的與高斯的假設相矛盾嗎？因為，我的意思是，這些不同的搖擺動物物種真的在爭奪相同的食物嗎？我不這么認為。我認為他們更像是，你知道，幾乎是合作，這樣他們就不必競爭了。女教授：太好了！對于不經(jīng)意的觀察者來說，搖擺者似乎與高斯的假設相矛盾，因為他們都生活在同一個地方，吃同樣類型的昆蟲。

但如果你更仔細地觀察這些鳥類，搖擺鳥物種并不是在同一時間為了同樣的食物而相互競爭。馬克，你能告訴我們什么是生態(tài)位嗎？男學生：植物或動物生活的地方，你知道，它的棲息地？女教授：比如說？男學生：嗯，就像生活在北極的北極熊，在冰原上&nbsp；北極是它的生態(tài)位，是它適應生存的棲息地。

女教授：好的。這就是大多數(shù)人的想法。。。。

但對于生物學家來說，生態(tài)位的概念還包括生物體在其棲息地中的功能，以及它如何與其他植物和動物物種、土壤、空氣、水等相互作用。好吧，現(xiàn)在讓我們把它們放在一起：

如果你有兩個相似的物種在同一生態(tài)位競爭，會發(fā)生什么？蘇珊？女學生：一個會支配另一個，最終消除它。女教授：好的。

那么，弱小的物種可以做些什么來提高它們的生存機會呢？女學生：也許就搬到別的地方，你知道，遠離競爭對手？

女教授：這是一種可能性。但是想想生態(tài)位的科學定義。想想搖擺器。

做記號男學生：也許它可以在棲息地找到一些新的運作方式，這樣它就不必與優(yōu)勢物種競爭了。保持相同的棲息地，但不是完全相同的生態(tài)位。女教授：是的，有很多方法-優(yōu)勢物種在樹的一部分進食，而你在另一部分進食。。。。

男學生：如果占優(yōu)勢的物種需要大量的水，你會在很少的水里發(fā)展生存的能力嗎？女教授：你靠剩下的東西生存。水、食物、筑巢或繁殖地點等等。

三、Gause's Hypothesis托福聽力問題：

Q1:1.What is the main purpose of the lecture?

A.To explain why a species of warbler might become extinct

B.To discuss the evidence that led Gause to formulate his hypothesis

C.To examine a hypothesis about what happens when species compete

D.To identify factors that allow some species to dominate others

Q2:2.According to Gause's hypothesis,what happens when two similar species compete for limited resources in the same habitat?

A.Both species will develop new nutritional requirements.

B.Both species will change their behaviors.

C.One of the species will eliminate the other from the habitat.

D.One of the species will spread into a new habitat.

Q3:3.How do the five species of warbler described by the professor manage to coexist?Click on 2 answers

A.By using different materials to build their nests

B.By feeding in different sections of the tree

C.By eating different kinds of insects

D.By breeding at different times of the year

Q4:4.What is the professor's opinion about Gause's hypothesis?

A.She thinks that it has not been disproved.

B.She thinks it is contradicted by basic laboratory experiments.

C.She thinks that it cannot be adequately investigated.

D.She believes that it is contradicted by the competitive exclusion principle.

Q5:5.What does the professor imply about the relationship between an organism's niche and its habitat?

A.An organism's niche is exactly the same as its habitat.

B.An organism's niche is only partly defined by its habitat.

C.An organism's habitat is almost always more complex than its niche.

D.An organism can change its habitat but cannot change its niche.

Q6:6.Why does the professor says this:

A.To encourage other students to participate in the discussion.

B.To correct an error in the student's statement.

C.To encourage the student to answer more specifically.

D.To confirm that the student's answer is correct.

四、Gause's Hypothesis托福聽力答案：

A1:正確答案：C

A2:正確答案：C

A3:正確答案：BC

A4:正確答案：A

A5:正確答案：B

A6:正確答案：D

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