手机APP下载

您现在的位置: 首页 > 托福 > 托福听力 > 托福TPO真题听写 > 正文

托福TPO-18 Lecture 4

来源:可可英语 编辑:mike   VIP免费外教试听课 |  可可官方微信:ikekenet
 下载MP3到电脑  批量下载MP3和LRC到手机
加载中..

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

独白:听下面一段生物学的课程。
Well, it's finally looking like spring is arriving.
嗯,现在看来,春天终于要到来了。
The last of the winter snow would be melting away in a few days.
几天之后,最后的冬雪将会融化。
So before we close today, I thought I'd mention a biological event that's a part of the transition from winter to spring, something you can go outside and watch if you have some patience.
所以,在我们今天结束课程之前,我想谈谈一个与冬春换季有关的生物学事例,这个事情你们如果有耐心的话,自己出门儿就能观察到。
There is a small creature that lives in this area; you've probably seen it.
这个片区内生活着一群小动物—你们很可能已经见过了。
It's the North American wood frog.
名字叫做北美林蛙。
Now the wood frog's not that easy tosspot since it stays pretty to close to the ground, under leaves and things and it blends in really well with its background as you can see.
现在林蛙不是特别好找,因为它们和地面贴得很近,而且藏在树叶等与它们外形相似、可以掩盖它们踪迹的隐蔽物下面。
But they are worth the effort because they do something very unusual, something you might not have even thought possible.
但是,它们值得你们费这番功夫,因为它们有一个非常奇妙的本领,这项本领你们想来绝对不可思议。
OK North American wood frogs live over a very broad territory or range.
好的,北美林蛙生活的地域是非常广阔的,
They're found all over the northeastern United States and all through Canada and Alaska, even inside the Arctic Circle.
从美国北部一直到加拿大和阿拉斯加甚至到北极圈,你们都能够看到它的身影。
No other frog is able to live that far and north.
没有另外一种蛙类可以生活在如此遥远的北地。
But wherever they live, once the weather starts to turn cold and the temperature starts to drop below freezing, as soon as the frog even touches an ice crystal or a bit of frozen ground, well, it begins to freeze.
但不管它们到底生活在那一个地方,一旦天气变冷,气温达到冰点以下,甚至只要林蛙碰到了一小点冰渣或冻土,它马上就会被冷冻起来。
Yeah...yes to me. You look a little bit taken aback.
嗯,我觉得是这样的。你们看上去有点吃惊?
Wait, you mean it's still alive but it freezes, solid?
等一下,您的意思是,它是活着的,但它是冰冻、不动的?
Well, almost. Ice forms in all the spaces outside the cells but never within a cell.
嗯,差不多吧!在林蛙的体内,除了细胞之外的空间里,到处都是冰。
But… then how does its heart beat?
但是…这样的话,它的心脏怎么跳动呢?
It doesn't.
已经不跳了。
But…then how could it…
但是,那样它怎么…
You are gonna do such a thing?
你是想知道这是怎么一回事吗?
Well, that first touch of ice apparently triggers a biological response inside the frog.
嗯,林蛙接触冰这个动作触发了林蛙体内的生理反应。
That first of all starts drawing water away from the center of its body, so the middle part of the frog, its internal organs, its heart, lungs, liver, these start getting drier and drier while the water that's being pulled away is forming a puddle around the organs just underneath the skin.
首先,这个反应会导致体腔内脱水,所以,在林蛙的中部,它的内部器官,包括心脏、肺、肝都会变得越来越干燥。
And then that puddle of water starts to freeze.
其后,它的蹼也会脱水结冰。
OK, up to known, the frog's heart is still beating, right? Slower and slower but…and in those last few hours before it freezes, it distributes glucose, a blood sugar throughout its body, its circulatory system, sort of acts like an antifreeze.
好的,到了现在这一步,林蛙的心脏依旧是在跳跃,对吧?越来越慢,对的…到结冰前的几个小时里,它的体内会释放葡萄糖这一血糖到全身的循环系统,这种葡萄糖似乎起到的是抗冻剂的作用。
A solution of antifreeze like you put in your car in the winter?
林蛙的这种释放葡萄糖的这种做法,即像我们在冬季往车里加抗冻剂一样吗?
Well, you tell me.
嗯,一会儿我讲完了你来告诉我吧!
In frogs, the extra glucose makes it harder for the winter inside the cells to freeze.
在林蛙体内,超量的葡萄糖会使得它们在冬季时细胞内部很难结冰。
So the cells stay just slightly wet, enough so that they can survive the winter.
所以,那时细胞仅仅会湿润一些,而这个湿度恰恰是保证它们在冬季的生存的程度。
Then after that, the heart stops beating altogether.
等到了那时,心脏的全部机能都会停止。
So is that the same?
所以,你还觉得你的比喻恰当吗?
I don't really know, but how long does it stay that way?
我真的不知道,不过,这种状态会持续多久呢?
Well, it could be days or months, all winter in fact but umm, see the heart really doesn't need to do any pumping now because the blood is frozen too.
嗯,长则几个月,甚至整个冬天,短则几天。实际上,嗯,因为心脏不需要输送血液,因为血液也是凝固的。
I just, I guess I just don't see how it isn't, you know, clinically dead.
我想,只是这样想,我不明白,它这种状态卫生么还是活着的,因为按照临床医学的经验来说,它已经死了。
Well, that's the amazing thing and how it revives is pretty amazing too.
嗯,那就是它的神奇所在!
After months without a heartbeat, spring time came around again, the earth starts to warm up and suddenly one day, ping, a pulse, followed by another one, then another until maybe ten, twelve hours later, the animal is fully recovered.
并且,它的解冻过程,也是令人吃惊的。在长达数月的心脏停跳期后,春季再次降临,地球又重新开始温暖如春,突然某一天,一声脉搏的颤动之后,接着又来了一个…脉搏恢复了大概 10 到 12 个小时之后,林蛙就彻底恢复了。
And does the thawing process have some kind of trigger as well?
那么这种解冻的过程是否也有一个触发点呢?
Well, we are not sure actually, the clearer thing is even though the sun is warning the frog up on the outside, its inside thaw out first, the heart and brain and everything.
嗯,我们目前也不清楚。我们可能会想到的是,当温暖的阳光叫醒青蛙之后,它的躯体内部包括大脑、心脏等会率先恢复。
But somehow it all just happens that way every spring.
但事实上,每次春季的时候,林蛙的身体解冻是一次性到位的。
But after they thaw does it affect them like their lifespan?
但目前还没有关于其寿命的证据。但是,在解冻之后,这种经历会影响它的寿命吗?
Well, hmm, we really don't know a lot about how long a wood frog normally lives, probably just a few years but there is no evidence its longevity. It does have some other impacts though.
嗯,我们现在还没有研究清楚一只林蛙正常情况下会存活多久,有可能是几年,但这个过程对林蛙的其他方面倒有一定影响。
In studies, we found that when it comes to reproduction, freezing diminishes the mating performance of males.
一些研究中,我们发现到了繁殖季,有过冰冻经历的雄性林蛙交配次数会减少。
After they've been frozen and thawed of course, they don't seem quite as vocal.
在他们冰冻—解冻之后,它们鸣叫求偶的欲望并不十分强烈。
They move slower and they seem to have a harder time recognizing a potential mate.
它们跑动得很慢,而且寻找雌性交配对象时会有麻烦。
So if the male frog could manage not to go through this freezing cycle, he'd probably have more success in mating.
所以,如果雄性林蛙能够设法避免进入冰冻周期的话,它交配的成功率就会大一些。

重点单词   查看全部解释    
internal [in'tə:nəl]

想一想再看

adj. 国内的,内在的,身体内部的

 
solution [sə'lu:ʃən]

想一想再看

n. 解答,解决办法,溶解,溶液

联想记忆
vocal ['vəukəl]

想一想再看

adj. 声音的,口述的,歌唱的
n. 元音,

联想记忆
evidence ['evidəns]

想一想再看

n. 根据,证据
v. 证实,证明

联想记忆
cell [sel]

想一想再看

n. 细胞,电池,小组,小房间,单人牢房,(蜂房的)巢室

 
territory ['teritəri]

想一想再看

n. 领土,版图,领域,范围

联想记忆
range [reindʒ]

想一想再看

n. 范围,行列,射程,山脉,一系列
v. 排

 
unusual [ʌn'ju:ʒuəl]

想一想再看

adj. 不平常的,异常的

联想记忆
potential [pə'tenʃəl]

想一想再看

adj. 可能的,潜在的
n. 潜力,潜能

 
freeze [fri:z]

想一想再看

v. 冻结,冷冻,僵硬,凝固
n. 结冰,冻结

 

    阅读本文的人还阅读了:
  • 托福TPO-18 Conversation 2 2014-01-06
  • 托福TPO-18 Lecture 3 2014-01-07
  • 托福TPO-19 Conversation 1 2014-01-13
  • 托福TPO-19 Lecture 1 2014-01-14
  • 托福TPO-19 Lecture 2 2014-01-15
  • 新东方托福网络课程:试听更多托福网络课程>>

    关键字: TPO 托福 听写 训练 练习

    发布评论我来说2句

      可可英语官方微信(微信号:ikekenet)

      每天向大家推送短小精悍的英语学习资料.

      添加方式1.扫描上方可可官方微信二维码。
      添加方式2.搜索微信号ikekenet添加即可。