Gause's Hypothesis托福听力原文翻译及问题答案

Gause's Hypothesis托福听力原文翻译及问题答案

一、Gause's Hypothesis托福听力原文：

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托福听力中文翻译：

旁白：在生物课上听一部分讲座。

女教授：好吧。回到20世纪30年代，一位名叫G.F.高斯的生物学家首次提出了所谓的“高斯假说”。

高斯说，每当你有两个相似的物种竞争相同的有限资源时，其中一个会有某种优势，无论多么微小，最终都会使这个物种占据主导地位，最终排斥另一个物种，甚至导致它灭绝。这就是为什么高斯的假设被称为“竞争排斥原理”。高斯做了一些实验室实验，比如把两种草履虫放在同一个环境中，它们必须竞争相同的食物。他发现，随着时间的推移，一个物种始终能够将另一个物种赶出栖息地，将其从栖息地中消除，正如他的假设所预测的那样。现在，对高斯假设的早期批评之一是，“当然，它在简单的实验室实验中起作用，在受控环境中只有两个竞争物种。但当应用于自然生态系统时，该假设会分崩离析，因为那里的情况更复杂。”

事实上，在现实世界中，有很多例子似乎与假设相矛盾&nbsp；例如，在美国东北部新英格兰的森林中，有一些小型鸣鸟，叫做莺。然而，这五种摇摆物种都设法共存-一个物种不存在优势，也不存在另一个物种排斥。。。。

这怎么可能？

事实证明，一种摇摆的物种在最上面的树枝上觅食，而其他物种则喜欢中间的树枝，其他物种则向树的底部觅食。此外，每种摇摆动物在一年中的不同时间繁殖。这样，鸟类喂食小鸡时的食物需求高峰期因物种而异；

女教授：是的，马克。

男学生：但这真的与高斯的假设相矛盾吗？因为，我的意思是，这些不同的摇摆动物物种真的在争夺相同的食物吗？我不这么认为。我认为他们更像是，你知道，几乎是合作，这样他们就不必竞争了。女教授：太好了！对于不经意的观察者来说，摇摆者似乎与高斯的假设相矛盾，因为他们都生活在同一个地方，吃同样类型的昆虫。

但如果你更仔细地观察这些鸟类，摇摆鸟物种并不是在同一时间为了同样的食物而相互竞争。马克，你能告诉我们什么是生态位吗？男学生：植物或动物生活的地方，你知道，它的栖息地？女教授：比如说？男学生：嗯，就像生活在北极的北极熊，在冰原上&nbsp；北极是它的生态位，是它适应生存的栖息地。

女教授：好的。这就是大多数人的想法。。。。

但对于生物学家来说，生态位的概念还包括生物体在其栖息地中的功能，以及它如何与其他植物和动物物种、土壤、空气、水等相互作用。好吧，现在让我们把它们放在一起：

如果你有两个相似的物种在同一生态位竞争，会发生什么？苏珊？女学生：一个会支配另一个，最终消除它。女教授：好的。

那么，弱小的物种可以做些什么来提高它们的生存机会呢？女学生：也许就搬到别的地方，你知道，远离竞争对手？

女教授：这是一种可能性。但是想想生态位的科学定义。想想摇摆器。

做记号男学生：也许它可以在栖息地找到一些新的运作方式，这样它就不必与优势物种竞争了。保持相同的栖息地，但不是完全相同的生态位。女教授：是的，有很多方法-优势物种在树的一部分进食，而你在另一部分进食。。。。

男学生：如果占优势的物种需要大量的水，你会在很少的水里发展生存的能力吗？女教授：你靠剩下的东西生存。水、食物、筑巢或繁殖地点等等。

三、Gause's Hypothesis托福听力问题：

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托福听力答案：

A1:正确答案：C

A2:正确答案：C

A3:正确答案：BC

A4:正确答案：A

A5:正确答案：B

A6:正确答案：D

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