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托福TPO-15 Lecture 4

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

独白:听一段生物学的课堂演讲
Professor:OK. We've been talking till now about the two basic needs of a biological community-an energy source to produce organic materials, you know ah, food for the organism, and the waste recycling or breakdown of materials back into inorganic molecules, and about how all this requires photosynthesis when green plants or microbes convert sunlight into energy and also requires microorganisms, bacteria, to secrete chemicals that break down or recycle the organic material to complete the cycle.
教授:好了。我们一直在讲生物群体的两种基本需求-能源资源产出有机物质,你们知道的,有机物的食物,以及废物回收或者物质破坏回归无机分子,以及当绿色植物或者微生物将阳光转化为能源时,所有这些都需要光合作用,还需要微生物、细菌来分泌化学物质来分解或者再循环这些有机物质,来完成循环。
So, now we are done with this chapter of the textbook, we can just review for the weekly quiz and move on to the next chapter, right?
那么,现在我们完成了教科书上这章的内容了,是吧?
Well, not so fast.
嗯,还没有这么快。
First, I'd like to talk about some discoveries that have challenged one of these fundamental assumptions about what you need in order to have a biological community.
首先我来讲一些发现,这些发现就挑战了够成生物群的基本需要的基本假定。
And, well, there actually were quite a few surprises.
而且,事情上有很多让人感到惊奇的地方。
It all began in 1977with the exploration of hydrothermal vents on the ocean floor.
一切始于 1977 年的一次海底上深海热泉的探索。
Hydrothermal vents are cracks in the Earth's surface that occur, well, the ones we are talking about here are found deep at the bottom of the ocean.
深海热泉是地球表面存在的裂缝,我们说的这个就是在海底的裂缝。
And these vents on the ocean floor, they release this incredibly hot water, 3-4 times the temperature that you boil water at because this water has been heated deep within the Earth.
这些海底的出口,排除及其热的水,温度比开水还要高 3 到 4 倍,因为这些水是从地球内部加热的。
Well about 30 years ago, researchers sent a deep-sea vessel to explore the ocean's depth, about 3kilometers down, way deep to ocean floor, No one had ever explored that far down before.
大概 30年前,研究人员派出了一个深海船来探察海洋深度,到海洋底部大约是 3 千公里深,之前从里没有人到如此的深度来探索过。
Nobody expected there to be any life down there because of the conditions.
由于下面的这种环境,没有人想过下面会有生命。
First of all, sunlight doesn't reach that far down so it's totally dark.
首先,阳光不能到达那么远,因此下面是漆黑一片。
There couldn't be any plant or animal life since there's no sunlight, no source of energy to make food.
也不可能有任何动植物,因为那里没有阳光,没有能源来提供食物。
If there was any life at all, it'd just be some bacteria breaking down any dead materials that might have fallen to the bottom of the ocean. And?
如果有生命的话,也就是一些分解任何死去物质的细菌可能跌落直海洋底层。还有呢?
Student:And what about the water pressure?
学生:还有水压。
Didn't we talk before about how the deeper down into the ocean you go, the greater the pressure?
我们之前不是讲过,越往海洋深度去,压强就越大吗?
Professor:Excellent point!
教授:说到点子上了。
And not only the extreme pressure, but also the extreme temperature of the water around these vents.
而且不仅是极大的压强,还有这些出口附近水的温度。
If the lack of sunlight didn't rule out the existence of a biological community down there then these factors certainly would, or so they thought.
如果阳光的缺失没有使这里的生物群体消失的话,那么这些因素也会的,人们起初这么想。
Student:So you are telling us they did find organisms that could live under those conditions?
学生:那么你是在说他们在那种环境下找到有机物了?
Professor:They did indeed, something like 300 different species.
教授:确实。找到了大概 300 个物种。
Student:But... but how could that be? I mean without sunlight, no energy, no no …
学生:但是那怎么可能呢?我的意思是说没有阳光,没有能源,没有…
Professor:What they discovered was that microorganisms, bacteria, had taken over both functions of the biological community-the recycling of waste materials and the production of energy.
教授:他们找到的是有两种生物群体功能的微生物、细菌-废物循环及能源再生。
They were the energy source.
他们就是能源。
You see, it turns out that certain microorganisms are chemosynthetic -they don't need sunlight because they take their energy from chemical reactions.
你们看,原来有些微生物是化学合成的,他们不需要阳光,因为他们从化学作用中吸取能源。
So, as I said, unlike green plants which are photosynthetic and their energy from sunlight, these bacteria that they found at the ocean floor, these are chemosynthetic, which means that they get their energy from chemical reactions.
因此,正如我所说,和进行光合作用并从阳光中吸取能源的绿色植物不一样,这些人们在海底发现的细菌是化学合成的,意味着他们通过化学作用来获得能源。
How does this work?
那是怎么回事呢?
As we said, these hydrothermal vents are releasing into the ocean depth this intensely hot water and here is the thing, this hot water contains a chemical called hydrogen sulfide, and also a gas, carbon dioxide.
正如我们说的,海底热泉往海中中释放及其热的水,是这么回事,这种热水包含化学物质硫化氢和一种气体,就是二氧化碳。
Now these bacteria actually combine the hydrogen sulfide with the carbon dioxide and this chemical reaction is what produces organic material which is the food for larger organisms.
这些细菌实际上就是硫化氢和二氧化碳的结合体,这种化学反应就产出了有机物质,也就是更大的有机体的食物。
The researchers had n ever seen anything like it before.
研究人员之前从来没有看过这种现象。
Student:Wow! So just add a chemical to a gas, and bingo, you've got a foodsupply?
学生:哇哦。那么说往气体里放点化学位置,然后就变成了食物供应?
Professor:Not just that!
教授:不仅是如此。
What was even more surprising were all the large organisms that lived down there.
更让人吃惊的是居住在那里的大有机物。
The most distinctive of these was something called the tube worm.
最有特点的一个叫做管虫。
Here, let me show you a picture.
来,我给你们看一张照片。
The tube of the tube worm is really, really long.
这管虫特别长。
They can be up to one and half meters long, and these tubes are attached to the ocean floor, pretty weird looking, huh?
可能达到一米半那么长。而这些管子是连在海底呢,长的很奇怪是吧?
And another thing, the tube worm has no. mouth, or digestive organs.
还有一个问题。管虫没有嘴,没有消化器官。
So you are asking how does it eat.
你们会问,那它怎么吃东西啊?
Well, they have these special organs that collect the hydrogen sulfide and carbon dioxide and then transfer it to another organ, where billions of bacteria live.
嗯,他们有一些特殊的器官能收集硫化氢和二氧化碳并能将其转化到另一个器官,那里有亿万个细菌。
These bacteria that live inside the tube worms, the tube worms provide them with hydrogen sulfide and carbon dioxide.
这些细菌生活在管虫里面, 管虫为他们提供硫化氢和二氧化碳。
And the bacteria, well the bacteria kind of feed the tube worms through chemosynthesis, remember that chemical reaction I described earlier.
而细菌呢,有点像通过化学合成的方式来为管虫提供食物,记得之前讲过的化学作用吧。

重点单词   查看全部解释    
transfer [træns'fə:]

想一想再看

n. 迁移,移动,换车
v. 转移,调转,调任

联想记忆
recycle [ri:'saikl]

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vt. 使再循环,再利用,再制
vi. 循环<

联想记忆
inorganic ['inɔ:'gænik]

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adj. 无机的,无生物的,非自然生长的

 
vessel ['vesl]

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n. 容器,器皿,船,舰
n. 脉管,血

 
release [ri'li:s]

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n. 释放,让渡,发行
vt. 释放,让与,准

联想记忆
species ['spi:ʃiz]

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n. (单复同)物种,种类

 
hydrogen ['haidridʒən]

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n. 氢

 
secrete [si'kri:t]

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v. 隐秘,隐藏,隐匿 v. 分泌

联想记忆
source [sɔ:s]

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n. 发源地,来源,原始资料

 
organic [ɔ:'gænik]

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adj. 器官的,有机的,根本的,接近自然的

 

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