動(dòng)物科學(xué)專業(yè)英語(yǔ)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 （吸進(jìn)） 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、產(chǎn)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 鹽）,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科學(xué)家說， 大約從三十億年前一直到現(xiàn)在，地球上的動(dòng)植物一直在進(jìn)行進(jìn)化， 并將繼續(xù)進(jìn) 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 初的動(dòng)植物都非常小，它們的體積比大頭針的針尖還小。我們可以說，最早的 動(dòng)植

10、物小得肉眼看不見。Such cells take food i（吸進(jìn)）and let waste out （排 出）through very small openings in their walls這類細(xì)胞通過細(xì)胞壁上非常小的 小孔吸進(jìn)養(yǎng)分并排出廢物。They do not give birth to（生育）new cells, but,strange to say, divide to become two daughter cel它們不生育新的細(xì)胞，但說來 奇怪,它們分裂成為兩個(gè)子細(xì)胞。Life began, men think, in the salty sea. 人們相信,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、產(chǎn)生）.在靠近陸地的地方，海水較淺，非常 小的單細(xì)胞生物產(chǎn)生了。The cells in our bodies all have water in them, though they are of different sorts. 我們體內(nèi)的細(xì)胞雖然有不同的種類,但都含有水份。 This water has in it about the same amount of salt, com

12、mon table sal食鹽），as that in the water of sea in which the earliest organisms swam在這種水里都含有鹽分，即普通的食鹽, 其含量與最早期生物體浮游過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那時(shí)的水比現(xiàn)在的 海水鹽分少一些。在幾十億年的時(shí)

13、間里，河流將越來越多的鹽從陸地沖到海里。The sea has become more salty. The water in our bodies does not become more salty. 海變得更咸了。我們體內(nèi)的水并沒有變咸。 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. 即使我們將大量的鹽吃進(jìn)血液，肌體也能自動(dòng)控制血液中應(yīng)該保 持的含鹽量。 And the same is

14、true if we let much salt out through the skin when we get overheated. 假如我們因?yàn)槭軣岫鴱钠つw排出了大量鹽分，情況也是這 樣。Then we have to eat something that will give us new supplies of 羈時(shí)我們 不得不吃些能給我們補(bǔ)充鹽分的東西。The first living things, though they were too small to be seen, were eating, growing organism which divided to becom

15、e like them最早的生命物質(zhì)，雖然小 得看不見，但它們卻是在不停地吃、不停地生長(zhǎng)的有機(jī)體，并且它們分裂成為 與它們相同的個(gè)體。Under a microscope,a cell looks like a bit of clear jelly with a thin wall round it. 在顯微鏡下，細(xì)胞看上去就像一滴透明的膠狀物體（果凍），周圍都 有一層很薄的壁。 In every cell there is a part like a little ball. This is the nucleus, which organizes the work of the cell.

16、 每個(gè)細(xì)胞里都有這么一個(gè)像小球一樣的部 分。這就是細(xì)胞核，它管理著細(xì)胞的一切活動(dòng)。 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.雖然細(xì)胞核已經(jīng)發(fā)現(xiàn)250年了，但認(rèn)識(shí)細(xì)胞核的 作用還是近一百年的事。 正

17、是細(xì)胞核，使得細(xì)胞做著該做的事（執(zhí)行著正常功 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.簡(jiǎn)而言之，所有的生命物質(zhì)都是由這些單細(xì)胞生物體發(fā)展 而來。它們由這些最初的，簡(jiǎn)單的生命物質(zhì)經(jīng)過多次轉(zhuǎn)變一步步進(jìn)化而來的。Our bodies and the bodies of the plants and animals we see about us are highly complex in their structure. 我們的機(jī)體和我們能夠在我們周圍看到的動(dòng)植物的 機(jī)體結(jié)構(gòu)是極為復(fù)雜的。 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. 它們是由數(shù)以億萬(wàn)計(jì)的細(xì)胞構(gòu)成的，這些細(xì)