动物科学专业英语文章

1、CellsThrough about three billions （3,000,000,000） years, scientists says, the developmentsof plants and animals on our earth have been going on. At first both were very small, much less than a pin point in size. We might say that the first plants or animals weretoosmall for mans eyeto see. Such cell

2、s take food in （吸进） and let waste out （排出） through very small openings in their walls. They do not give birth to（生育）new cells but, strange to say, divide to become two daughter cells.Life began, men think, in the salty sea. Near the land, where the waters were not deep, very small one-celled organis

3、ms came into bei形g成、产生）.The cells in our bodies all have water in them, though they are of different sorts This water has in it about the same amount of salt, common table s（食 盐）,as that in the water of sea in which the earliest organisms swam That water was little less salty than sea water is today

4、 In billions of years, the rivers have washed down more and more salt from the land into the sea The sea has become more salty The water in our bodies does not become more salty Even if we eat a great amount of salt in our food，the body automatically controls how much it will keep in the blood strea

5、m And the same is true if we let much salt out through the skin when we get overheated Then we have to eat something that will give us new supplies of saltThe first living things, though they were too small to be seen, were eating, growing organism which divided to become like themUnder a microscope

6、,a cell looks like a bit of clear jelly with a thin wall round it. In every cell there is a part like a little ball. This is the nucleus, which organizes the work of the cell. Though cells were discovered two and a half centuries ago, itis only in the last hundred years that knowledge of the work of

7、 the nucleus has developed. It is this nucleus which keeps the cell working at what has to be done.In short, all living things are developments from these one-cell organisms. They have developed step by step through change upon change from these first, simple, living things. Our bodies and the bodie

8、s of the plants and animals we see about us are highly complex in their structure. They have in them millions of millionsof cells, some doing one sort of work, some another. Every different cell has its own sort of work to do.CellsThrough about three billions （3,000,000,000） years, scientists says,

9、the developments of plants and animals on our earthave been going q科学家说， 大约从三十亿年前一直到现在，地球上的动植物一直在进行进化， 并将继续进 行下去。 At first both were very small, much less than a pin point in size. We might say that the first plants or animals weretoo small for mans eyeto see. 最 初的动植物都非常小，它们的体积比大头针的针尖还小。我们可以说，最早的 动植

10、物小得肉眼看不见。Such cells take food i（吸进）and let waste out （排 出）through very small openings in their walls这类细胞通过细胞壁上非常小的 小孔吸进养分并排出废物。They do not give birth to（生育）new cells, but,strange to say, divide to become two daughter cel它们不生育新的细胞，但说来 奇怪,它们分裂成为两个子细胞。Life began, men think, in the salty sea. 人们相信,生命是起源

11、于咸的海水 中。 Near the land, where the waterswere not deep, very small one-celled organisms came into being形成、产生）.在靠近陆地的地方，海水较浅，非常 小的单细胞生物产生了。The cells in our bodies all have water in them, though they are of different sorts. 我们体内的细胞虽然有不同的种类,但都含有水份。 This water has in it about the same amount of salt, com

12、mon table sal食盐），as that in the water of sea in which the earliest organisms swam在这种水里都含有盐分，即普通的食盐, 其含量与最早期生物体浮游过的海水中的含量大致相同That water waslittle less salty than sea water is today. In billions of years, the rivers have washed down more and more salt from the land into the sea那时的水比现在的 海水盐分少一些。在几十亿年的时

13、间里，河流将越来越多的盐从陆地冲到海里。The sea has become more salty. The water in our bodies does not become more salty. 海变得更咸了。我们体内的水并没有变咸。 Even if we eat a great amount of salt in our food，the body automatically controls how much it will keep in the blood stream. 即使我们将大量的盐吃进血液，肌体也能自动控制血液中应该保 持的含盐量。 And the same is

14、true if we let much salt out through the skin when we get overheated. 假如我们因为受热而从皮肤排出了大量盐分，情况也是这 样。Then we have to eat something that will give us new supplies of 羁时我们 不得不吃些能给我们补充盐分的东西。The first living things, though they were too small to be seen, were eating, growing organism which divided to becom

15、e like them最早的生命物质，虽然小 得看不见，但它们却是在不停地吃、不停地生长的有机体，并且它们分裂成为 与它们相同的个体。Under a microscope,a cell looks like a bit of clear jelly with a thin wall round it. 在显微镜下，细胞看上去就像一滴透明的胶状物体（果冻），周围都 有一层很薄的壁。 In every cell there is a part like a little ball. This is the nucleus, which organizes the work of the cell.

16、 每个细胞里都有这么一个像小球一样的部 分。这就是细胞核，它管理着细胞的一切活动。 Though cells were discoveredtwo and a half centuries ago, itis only in the last hundred years that knowledge of the work of the nucleus has developed. It is this nucleus which keeps the cell working at what has to be done.虽然细胞核已经发现250年了，但认识细胞核的 作用还是近一百年的事。 正

17、是细胞核，使得细胞做着该做的事（执行着正常功 能）。In short, all living things are developments from these one-cell organisms. They have developed step by step through change upon change from these first, simple, living things.简而言之，所有的生命物质都是由这些单细胞生物体发展 而来。它们由这些最初的，简单的生命物质经过多次转变一步步进化而来的。Our bodies and the bodies of the plants and animals we see about us are highly complex in their structure. 我们的机体和我们能够在我们周围看到的动植物的 机体结构是极为复杂的。 They have in them millions of millionsof cells, some doing one sort of work, some another. Every different cell has its own sort of work to do. 它们是由数以亿万计的细胞构成的，这些细