两栖类文章难度较高，很可能涉及进化理论的对比，可能考到理论的主要观点或者对比的焦点。同时学生应该注意教授的总结内容。
TPO 21 - Biology (Snake Evolution)
Professor: Probably back in some previous biology course you learned that snakes evolved from lizards, and that the first snakes weren’t venomous and then along came more advanced snakes, the venomous snakes. Ok, venomous snakes are the ones that secrete poisonous substances or venom, like the snakes of the viper family or cobras. Then there is non-venomous snakes like constrictors and pythons. Another family of snakes, the colubrids, don’t really fit neatly into either category though. Colubrids, and you probably learned this too, although they are often classified as venomous snakes, they are actually generally non-venomous. They are classified as venomous snakes because they resemble them, their advanced features more than the other non-venomous snakes.
TPO24 lecture 1 一种爬行动物—鳄鱼。鳄鱼之间的互动方式多种多样，其中一种就是发声法。
Professor: OK. For today, let's look at a reptile, a predator that hasn't evolved much in the last seventy million years. No discussion of reptiles would be complete without some mention of crocodiles.
Now, we tend to think of crocodiles as, uh, kind of solitary, hiding out in a swamp, uh, kind of mysterious creatures. But we are finding out that they aren't as isolated as they seem. In fact, crocodiles interact with each other in a variety of ways. One way is with vocalizations, you know, sounds generated by the animal. This is true of the whole crocodile family, which includes crocodiles themselves, alligators, etc.
Take American alligators. If you were to go to a swamp during the breeding season, you'd hear a chorus of sounds, deep grunts, hisses, these are sounds that male alligators make.
And some of them are powerful enough to make the water vibrate. This sends a strong, go-away message to the other males. So the alligator can focus on sending other sound waves through the water, sound waves that you and I couldn't even hear since they are at such low frequency. But they do reach the female alligator, who then goes to find and mate with the male.
TPO 54-Lecture 1
三大生态类群就是浮游生物、游泳生物和底栖生物了。
鱼类一般统一被称为游泳动物，因为大部分的鱼类有发达的运动器官，游泳能力强，相应的还有一些头足类、哺乳类（鲸/海豚/海豹）、爬行类（海龟）、海鸟之类的。
浮游生物缺乏发达的运动器官、只能随水流移动。
Migration of Zooplankton
And the sea is teeming with tiny organisms, but they don't get as much popular attention as say, whales.
Microscopic algae just aren't as exciting I suppose. And yet those organisms are the foundation of the bulk of the marine food chain. Without plankton which is the global term for these tiny organisms, there will be no whales.
Plankton is found both in fresh water and marine environments. Again it's a term we use for any small organisms that float along with the current, either because they are too small or weak to swim against it, or because they don't have any capacity at all to move by themselves.
TPO 17-Lecture 4
Octopus
Ok, now I want to talk about an animal that has a fascinating set of defense mechanisms. And that’s the octopus, one of the unusual creatures that live in the sea. The octopus is prey to many species, including humans, so how does it escape its predators? … Just like Proteus, the octopus can go through all kinds of incredible transformations. And it does this in three ways: by changing color, by changing its texture, and by changing its size and shape. For me, the most fascinating transformation is when it changes its color. It’s a normal skin color, the one it generally presents, is either red or brown or even grey, and it’s speckled with dark spots. But when it wants to blend in with its environment to hide from its enemies, it can take on the color of its immediate surroundings: the ocean floor, a rock, a piece of coral, whatever. Charles?
这一段是描写章鱼(octopus)的学术讲座，当教授提及now I want to talk about…”这类表达，考生应当十分敏感，这是主旨题的典型信号句。对于生物学讲座，一般情况下教授都会在讲课开始时给出话题重点，比如某种生物或某个概念。
这也是其他学科类段子的共性。在此段开始，教授道出了主题：章鱼的御敌方法。那么接下来就该说说具体的方法了：通过改变颜色，质地和形状。这三种方式都用介词by引出，应当引起考生注意。
TPO10 lecture 1鲸鱼由陆上生物进化为海洋生物的证据。首先说到陆生鲸的化石分析可见鲸鱼是陆生生物。接着，又把路行鲸鱼和现在鲸鱼的DNA作比较，它们之间有一定的相似性。通过把DNA的比较发现鲸鱼是河马的远方亲戚。
TPO15 lecture 4关于深海热液喷泉口生命的探究，从喷泉口发现了大量的生物，震惊了科学界。
TPO23 lecture 3海豚可以发出两种声音。一种是我们大家都比较熟悉的声音，就是从它们的喷水口发出的声音。另一种声音是他们用以回声定位的咔嚓声，这种声音是海豚的充满空气的鼻囊里发出的。海豚鼻疣是具有独特的声学特征，它是运用鼻疣发声的。
TPO 49 - Reindeer
Professor: Okay, so that's how the arctic ground squirrel's able to cope in this extreme environment. Now let's talk about your reading assignment, about reindeer, also typically found in Siberia and other far northern regions. Who would like to start off? Yes, Mike
Male Student: Well, for one thing, they've got thick hair all over their body, even on their noses.
Professor: Yes.They are very well insulated, and the thickness of their fur varies depending on the season. Good. Yes?
Female Student: Um...newborn reindeer are very adult-like, like they can stand as soon as they're born, and by their second day they can already run as fast as a human.
TPO18 lecture 4北美的wood frog 有一种神奇的过冬现象，就是心跳停止了，但是它们还活着。然后讲了下这种现象的原理以及这种现象的影响。
TPO20 lecture 4本文主要讲述一种动物兔子，通过本身的特性可以适应恶劣环境。
TPO21 lecture 3从全文来看，教授先提到蛇的分类，在提到一个关于蛇进化的新理论，接着讲述了一个实验是如何来证明这个理论的。
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