Part I
Professor: OK, we've being talking till now about the two basic needs of biological community: an energy source to produce organic materials, you know, uh, food for the organisms and the waste recycling or breakdown of materials back into inorganic molecules, and about how all this requires photosynthesis, when green plants or microbes converts sunlight into energy, and also requires microorganisms, bacteria, to secrete chemicals that break down or recycle the organic material to complete the cycle.
So, now we're done with this chapter of the textbook, we can just review for the weekly quiz and move on to the next chapter, right? Well, not so fast. 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. And, well, there actually were quite a few surprises!
首先，我想谈谈一些挑战了这些基本假设之一的发现，即需要什么条件才能生成一个生物群落。
1. community|kəˈmju:nəti|
noun. a group of plants and animals growing or living in the same place or environment （动植物的）群落
E.g.: a community of bacteria
一组菌群
2. breakdown|ˈbreɪkdaʊn|
noun. the breaking of a substance into the parts of which it is made 分解
E.g.: the breakdown of proteins in the digestive system
蛋白质在消化系统中的分解
3. molecule 分子; proton 质子; atom 原子; neutron 中子; electron 电子; photon 光子
4. photosynthesis|ˌfəʊtəʊˈsɪnθəsɪs|
noun. the process by which green plants turn carbon dioxide and water into food using energy obtained from light from the sun 光合作用
E.g.: In apple trees photosynthesis occurs almost exclusively in the leaves.
苹果树的光合作用几乎只发生在叶内。
5. secrete |sɪˈkri:t|
verb. (of part of the body or a plant 身体或植物器官) to produce a liquid substance 分泌
E.g.: Insulin is secreted by the pancreas.
胰岛素是胰腺分泌的。
Part II
It all began in 1977 with the exploration of hydrothermalvents on the ocean floor. Hydrothermal vents are cracks in the Earth surface that occur, well, the ones we're talking about here, are found deep at the bottom of the ocean. And these vents on the ocean floor, they release this incredibly hot water, three to four times the temperature that you boil water at, because this water's being heated deep within the Earth.Well, about 30 years ago, researchers sent a deep-sea vessel to explore the ocean's depth, about three kilometers down, way deep to the ocean floor. No one had ever explored that far down before. Nobody expected there to be any life down there because of the conditions.
热液喷口是地球表面出现的裂缝，我们今天在这里谈论的是在海底深处发现的那些地表裂缝。
1. hydrothermal |ˌhaɪdrə'θɜməl|
adj. of or relating to hot water —used especially of the formation of minerals by hot solutions rising from a cooling magma 水热的;热液的
E.g.: In all hydrothermal deposits, the minerals formed are not solely the sulfide ore minerals.
在所有热液矿床中，所形成的矿物并不单单是硫化物矿石矿物。
2. vent |vent|
noun. an opening that allows air, gas or liquid to pass out of or into a room, building, container, etc. （空气、气体、液体的）出口，进口，漏孔
E.g.: Quite a lot of steam escaped from the vent at the front of the machine.
大量蒸汽从机器前部的排风口冒了出来。
3. vessel|ˈvesl|
noun. a large ship or boat 大船;轮船;舰
E.g.: A Moroccan fishing vessel and a South Korean cargo ship collided in rough seas.
一艘摩洛哥渔船与一艘韩国货船在波涛汹涌的大海上相撞了。
4. way|ˈvesl|
adv. very far; by a large amount 远远地;大大地;非常
E.g.: Way down in the valley to the west is the town of Freiburg.
从这里往西远远的山谷中是弗赖堡镇。
Part III
First of all, sunlight doesn't reach that far down so it's totally dark. There couldn't be any plant or animal life, since there's no sunlight, no source of energy to make food. 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. Ann?Student: And what about the water pressure? Didn't we talk before about how the deeper down into the ocean you go, the greater the pressure?Professor: Excellent point! And not only the extreme pressure, but also the extreme temperature of the water around these vents. 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.Student: So you're telling us they did find organism that could live under those conditions?Professor: They did indeed, something like three hundred different species.Student: But, but, how could that be? I mean, without sunlight, no energy, no, no...
如果真的有什么生命，那也只是一些细菌，它们靠分解可能掉到海底的死掉的生物为生。
1. rule out
to state that sth is not possible or that sb/sth is not suitable 把…排除在外；认为…不适合
E.g.: Police have not ruled out the possibility that the man was murdered.
警方尚未排除那个男子是被谋杀的可能性。
2. species |ˈspi:ʃi:z|
noun. a group into which animals, plants, etc. that are able to breed with each other and produce healthy young are divided, smaller than a genus and identified by a Latin name 种，物种（分类上小于属）
E.g.: a conservation area for endangered species
濒危物种保护区
Part IV
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. They were the energy source.You see, it turns out that certain microorganisms are chemosynthetic–they don't need sunlight because they take their energy from chemical reactions. So, as I said, unlike green plants which are photosynthetic and get 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. How does this work?As we said, these hydrothermal vents are releasing into the ocean depth, this intensely hot water, and here's the thing, this hot water contains chemical called hydrogen sulfide and also a gas, carbon dioxide. 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. The researchers have never seen anything like it before.
所以，正如我所说，不像绿色植物是进行光合作用从阳光中获取能量，这些在海底发现的细菌，它们是进行化学合成，这意味着它们从化学反应中获取能量。
1. take over
if you take over a job or role or if you take over, you become responsible for the job after someone else has stopped doing it 接替;接任;接手
E.g.: His widow has taken over the running of his empire, including six London theatres.
他的遗孀已接手管理他创下的帝国，其中包括 6 家伦敦剧院。
2. chemosynthesis |ˌkemoʊ'sɪnθəsɪs|
noun. synthesis of carbohydrate from carbon dioxide and water; limited to certain bacteria and fungi 化学合成：用来自化学反应(而不是吸收光线)的能量从二氧化碳和水合成碳水化合物。某些细菌和藻类进行这种合成。
3. depth |depθ|
noun. the deepest, most extreme or serious part of sth 最深处；深渊；极限
E.g.: The ship vanished into the depths.
船消失在了大海深处。
4. hydrogen sulfide 硫化氢; methane 甲烷; carbon dioxide 二氧化碳; carbon monoxide 一氧化碳; oxygen 氧气; hydrogen 氢气; nitrogen 氮气
Part V
Student: Wow! So just add a chemical to a gas and bingo! You've got a food supply?Professor: Not just that, what was even more surprising were all the large organisms that lived down there. The most distinctive of these was something called the tube worm. Here, let me show you a picture. The tube of the tube worm is really, really long. They can be up to one and a half meters long, and these tubes are attached to the ocean floor, pretty weird looking, huh?And another thing, the tube worm has no mouth or digestive organs. So you're asking, how does it eat? Well, they have this special organs that collect the hydrogen sulfide and carbon dioxide, and then transfer it to another organ where billions of bacteria live; these bacteria that live inside the tube worms, the tube worms provide them with hydrogen sulfide and carbon dioxide and the bacteria, well, the bacteria kind of feed the tube worms through chemosynthesis. Remember? That chemical reaction I described earlier.
他们有这个可以收集硫化氢和二氧化碳的特殊器官，然后把硫化氢和二氧化碳转移到另一个器官，那个器官里住着数十亿的细菌；这些细菌生活在管虫体内，管虫为它们提供硫化氢和二氧化碳，细菌则通过化学合成反过来喂养管虫。
1. bingo |ˈbɪŋgəʊ|
exclamation. used to express pleasure and/or surprise because you have found sth that you were looking for, or done sth that you were trying to do （事情如愿时说）好，瞧
E.g.: The computer program searches, and bingo! We've got a match.
电脑程序在搜索，瞧！找到匹配的了。
2. distinctive |dɪˈstɪŋktɪv|
adj. having a quality or characteristic that makes sth different and easily noticed 独特的；特别的；有特色的
E.g.: The male bird has distinctive white markings on its head.
雄鸟的头上有明显的白色斑纹。
3. digestive |daɪˈdʒestɪv|
adj. connected with the digestion of food 消化的；和消化有关的
E.g.: Peppermint oil is very good for regulating digestive disorders.
薄荷油能很有效地调节消化系统失调。
