Mutualism托福聽力原文翻譯及問題答案

Mutualism托福聽力原文翻譯及問題答案

一、Mutualism 托福聽力原文：

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

FEMALE PROFESSOR: OK. Today I'd like to spend some time going into more detail about symbiosis. Symbiosis. What is it? Anyone?

MALE STUDENT: I thought it's when two organisms are in a relationship that they both benefit from, well, at least that’s what I thought it was until I did the reading last night. Now I'm kinda confused about it because the book used that definition to describe mutualism.Could you explain the difference?

FEMALE PROFESSOR: Good. I was hoping that someone would bring that up. Sometimes scientists working in different fields use the term “symbiosis” to mean slightly different things, and it can get confusing, for example, when “symbiosis” is used as a synonym for “mutualism.” But there are quite a few of us out there who think there should be a clearer distinction made between the two.

Ok, where to begin... Um, the original definition of symbiosis is pretty simple. It simply means living together. So, any close relationship between two organisms of different species would be considered a symbiotic relationship, including positive and negative relationships.

Mutualism then is a kind of symbiosis, a specific type of symbiotic relationship where both organisms benefit somehow. So, your book is correct.

Now, I want to make it clear that, um, the positive result from being in a mutualistic relationship doesn't have to be equal for both organisms. It's not a one-to-one ratio here.

Is everyone with me so far? Symbiosis—general term, mutualism—a narrower, more specific kind of symbiosis.

Now let's take a closer look at mutualistic relationships. I'll start off by describing a case of mutualism that involves a certain butterfly species found in South Africa and Australia. It’s a good example of how dependence on a mutualistic relationship can vary.

OK, there's this butterfly family, and I'll spare you the fancy Latin name because it's not important for our purposes here. I'll call them coppers and blues, well…because most members of this family have blue or copper-colored wings. I think this is one of the most interesting cases of mutualism: These butterflies require the presence of ants to complete their life cycle—their interaction with ants is obligatory.

So this is what happens. A female butterfly of these coppers and blues will lay eggs only on vegetation where there’re ants of a particular species. The butterflies can smell…well, ants leave behind pheromones—a special chemical signal. The butterfly recognizes the ants'pheromones on the plant…and then the newly hatched butterflies, the caterpillars, will feed on this plant after they hatch from the eggs. As the caterpillar gets a little older and finds shelter under nearby rocks or stones to protect itself from predators, it’s always attended or escorted by ants. And it always makes its way back to the host plant to feed, guided by the ants—the ant escort service—so to speak.

Now why would the ants go through all this trouble? What's their benefit? Mary?

FEMALE STUDENT: It's probably related to food …

FEMALE PROFESSOR: Uh huh, you’re onto something …

FEMALE STUDENT: OK. Ants feed on sweet stuff, right? So the caterpillar must have some kind of special access to honey, or sugars, or something like that. Maybe caterpillars produce honey somehow. On second thought…I'm probably way off.

FEMALE PROFESSOR: You're pretty close, actually. The caterpillars have a “honey gland”—an organ that secretes an amino acid and carbohydrate liquid. The caterpillar secretes the liquid from the honey gland—rather large quantities—enough to feed several ants. But what makes this relationship obligatory for the caterpillar? Well, if the ants don’t feed regularly on the liquid from the caterpillar’s honey gland, the gland overloads and gets infected. The infection will kill the caterpillar and it'll never reach its final stage of development—becoming a butterfly. John?<br>

MALE STUDENT: OK. I just wanna make sure I'm following here. The caterpillar needs the ants, or it won't make it to the stage where it can become a butterfly. And, the ants do this because they get an easy meal out of it, right? But the ants don't absolutely need the caterpillar for survival 'cuz they can get food from other places, right? So it's still called mutualism even though it seems like the caterpillar's getting way more out of it?  Oh. Wait. You said they don't have to equally benefit.Never mind. Sorry.

FEMALE PROFESSOR: Yes, but there is a type of mutualism where the relationship is necessary for both organisms to survive.It's called obligatory mutualism. We'll talk about that in next class.

二、Mutualism 托福聽力中文翻譯：

旁白：在生物課上聽一節(jié)課的一部分。

女教授：好的。今天，我想花點(diǎn)時間詳細(xì)介紹一下共生。共生這是怎么一回事？任何人

男學(xué)生：我以為兩個有機(jī)體處于一種關(guān)系中時，它們都會從中受益，好吧，至少在我昨晚閱讀之前，我一直是這么認(rèn)為的?，F(xiàn)在我有點(diǎn)困惑了，因為這本書用這個定義來描述互惠主義。你能解釋一下區(qū)別嗎？

女教授：好。我希望有人能提出來。有時，在不同領(lǐng)域工作的科學(xué)家使用“共生”一詞來表示略有不同的事物，這可能會令人困惑，例如，當(dāng)“共生”被用作“互惠”的同義詞時但我們當(dāng)中有相當(dāng)多的人認(rèn)為，應(yīng)該對兩者進(jìn)行更明確的區(qū)分。

好的，從哪里開始。。。嗯，共生最初的定義很簡單。這僅僅意味著住在一起。因此，不同物種的兩種生物之間的任何密切關(guān)系都將被視為共生關(guān)系，包括積極和消極的關(guān)系。

互利共生是一種共生，一種特定類型的共生關(guān)系，兩種生物都能從中受益。所以，你的書是正確的。

現(xiàn)在，我想說明的是，嗯，互惠關(guān)系的積極結(jié)果不一定對兩種生物體都是平等的。這不是一對一的比例。

到目前為止大家都跟我在一起嗎？共生的總稱，互惠共生——一種更狹隘、更具體的共生。

現(xiàn)在讓我們仔細(xì)看看互惠關(guān)系。首先，我將描述一個互惠共生的案例，涉及在南非和澳大利亞發(fā)現(xiàn)的某種蝴蝶物種。這是一個很好的例子，說明對互惠關(guān)系的依賴是如何變化的。

好吧，這里有一個蝴蝶家族，我不想給你起這個花哨的拉丁名字，因為它對我們這里的目的并不重要。我會叫它們銅色和藍(lán)色，因為這個家族的大多數(shù)成員都有藍(lán)色或銅色的翅膀。我認(rèn)為這是互惠主義最有趣的例子之一：這些蝴蝶需要螞蟻的存在才能完成它們的生命周期。它們與螞蟻的互動是必須的。

這就是發(fā)生的事情。這種銅色和藍(lán)色的雌性蝴蝶只會在有特定種類螞蟻的植被上產(chǎn)卵。蝴蝶能聞到……嗯，螞蟻會留下信息素——一種特殊的化學(xué)信號。蝴蝶識別螞蟻在植物上的信息素……然后新孵出的蝴蝶，即毛蟲，從卵中孵化出來后，將以這種植物為食。隨著毛毛蟲年齡的增長，它會在附近的巖石或石頭下找到避難所，以保護(hù)自己免受捕食者的襲擊，它總是有螞蟻的陪伴。它總是在螞蟻的引導(dǎo)下返回寄主植物覓食，可以說是螞蟻?zhàn)o(hù)送服務(wù)。

螞蟻為什么要經(jīng)歷這些麻煩呢？他們的好處是什么？瑪麗？

女生：可能跟食物有關(guān)…

女教授：嗯，你發(fā)現(xiàn)了什么…

女學(xué)生：好的。螞蟻吃甜食，對嗎？因此，毛蟲必須有某種特殊的途徑獲得蜂蜜、糖或類似的東西。也許毛毛蟲會產(chǎn)生蜂蜜。再想想……我可能已經(jīng)走遠(yuǎn)了。

女教授：事實上，你很接近。毛毛蟲有一個“蜂蜜腺”——一個分泌氨基酸和碳水化合物液體的器官。毛蟲從蜂蜜腺分泌大量的液體，足以喂養(yǎng)幾只螞蟻。但是，是什么讓這種關(guān)系對毛毛蟲來說是必須的呢？嗯，如果螞蟻不定期食用毛蟲蜂蜜腺中的液體，那么蜂蜜腺就會超載并被感染。這種感染會殺死毛蟲，而且它永遠(yuǎn)也不會發(fā)展到成為蝴蝶的最后階段。約翰<br>

男學(xué)生：好的。我只是想確定我在這里。毛毛蟲需要螞蟻，否則它就無法變成蝴蝶。螞蟻這樣做是因為它們能很容易地從中得到一頓飯，對嗎？但是螞蟻并不完全需要毛蟲生存，因為它們可以從其他地方獲得食物，對嗎？所以它仍然被稱為互惠主義，盡管看起來毛毛蟲從中獲得了更多？哦等待你說過他們不必平等受益。不要介意。很抱歉

女教授：是的，但有一種互惠互利的關(guān)系，這種關(guān)系是兩種生物生存所必需的。這叫做強(qiáng)制性互惠主義。我們將在下節(jié)課上討論這個問題。

三、Mutualism 托福聽力問題：

Q1:1.What is the professor mainly discussing?

A. Different ways that scientists use the term “symbiosis”

B. A specific kind of symbiotic relationship between organisms

C. A butterfly species that competes with another insect species

D. Reasons why symbiosis is considered a subtype of mutualism

Q2:2.What does the professor imply about the term“symbiosis”?

A. It is often used with too narrow a meaning.

B. It is used incorrectly in the students' textbook.

C. The original definition is difficult to understand.

D. It is applied only to organisms of the same species.

Q3:3.How do the butterflies mentioned by the professor facilitate the relationship between caterpillars and ants of a certain species?

A. The butterflies have a sweet smell that attracts the ants.

B. The butterflies lay their eggs under rocks where the ants lay their eggs.

C. The butterflies lay their eggs on plants where the ants are present.

D. The butterflies identify a food source for both ants and caterpillars.

Q4:4.In the example the professor mentions, how do the ants benefit from their interaction with the caterpillars?

A. The caterpillars protect the ants' eggs from predators.

B. The caterpillars help the ants find a particular plant.

C. The caterpillars produce a liquid to prevent ants from getting infections.

D. The caterpillars produce a liquid from a species gland to feed the ants.

Q5:5.What aspect of mutualism does the professor illustrate with the example of the caterpillars and the ants?

A. Both organisms need the relationship for survival.

B. It is not necessary for both organisms to benefit equally from the relationship.

C. There is more benefit for the organism that is less dependent on the relationship.

D. The relationship does not need to be beneficial to both organisms.

Q6:6.What can be inferred about the student when she says this: (Female student) Maybe caterpillars produce honey somehow. On second thought . . . I'm probably way off.

A. She needs more time to think about the answer.

B. She is almost certain that caterpillars produce honey.

C. She thinks her statement may be misunderstood.

D. She doubts that her statement is correct.

四、Mutualism 托福聽力答案：

A1:正確答案：B

A2:正確答案：A

A3:正確答案：C

A4:正確答案：D

A5:正確答案：B

A6:正確答案：D

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