在线英语听力室

SSS 2010-01-29

时间：2010-05-20 02:30:36

搜索关注在线英语听力室公众号：tingroom，领取免费英语资料大礼包。

（单词翻译）

Organisms evolved sexual reproduction so they could stay one step ahead of parasites1. Or so the theory goes. But what about beasties that make babies without sex? How do they escape infection? A study in the journal Science suggests that for bdelloid rotifers, the answer is blowin’ in the wind.

Biologists believe that sex offers an evolutionary2 advantage because it promotes genetic4 diversity. Coming up with fresh new gene3 combinations should allow organisms to outsmart parasites, which are also continuously evolving. But if that theory is correct then bdelloid rotifers, freshwater invertebrates5 that haven’t had sex in at least 30 million years, should have been parasited into extinction6 long ago. Yet here they are, alive and well.

To find out why, scientists infected rotifers with a deadly fungus7. And they found that bdelloid rotifers can shake the infection by drying out, drifting away and then rehydrating once they land someplace moist but fungus-free. The fungi8 don’t survive the desiccation, so the longer the bdelloids stay dry, the better off they be.

So for celibate9 rotifers that want to stay clean, a good long dry spell is just what the doctor ordered.

 

—Karen Hopkin

 


分享到：


点击收听单词发音收听单词发音  

1 parasites a8076647ef34cfbbf9d3cb418df78a08     
寄生物( parasite的名词复数 )； 靠他人为生的人； 诸虫
参考例句：
  • These symptoms may be referable to virus infection rather than parasites. 这些症状也许是由病毒感染引起的，而与寄生虫无关。
  • Kangaroos harbor a vast range of parasites. 袋鼠身上有各种各样的寄生虫。
2 evolutionary Ctqz7m     
adj.进化的；演化的，演变的；[生]进化论的
参考例句：
  • Life has its own evolutionary process.生命有其自身的进化过程。
  • These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。
3 gene WgKxx     
n.遗传因子，基因
参考例句：
  • A single gene may have many effects.单一基因可能具有很多种效应。
  • The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。
4 genetic PgIxp     
adj.遗传的，遗传学的
参考例句：
  • It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
  • Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
5 invertebrates 7e45dc289993d00de9b9f14a70e51319     
n.无脊椎动物( invertebrate的名词复数 )
参考例句：
  • Insects and worms are all invertebrates. 昆虫和蠕虫都是无脊椎动物。 来自辞典例句
  • In the earthworm and many other invertebrates, these excretory structures are called nephridia. 在蚯蚓和许多其它无脊椎动物中，这些排泄结构称为肾管。 来自辞典例句
6 extinction sPwzP     
n.熄灭，消亡，消灭，灭绝，绝种
参考例句：
  • The plant is now in danger of extinction.这种植物现在有绝种的危险。
  • The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。
7 fungus gzRyI     
n.真菌，真菌类植物
参考例句：
  • Mushrooms are a type of fungus.蘑菇是一种真菌。
  • This fungus can just be detected by the unaided eye.这种真菌只用肉眼就能检查出。
8 fungi 6hRx6     
n.真菌，霉菌
参考例句：
  • Students practice to apply the study of genetics to multicellular plants and fungi.学生们练习把基因学应用到多细胞植物和真菌中。
  • The lawn was covered with fungi.草地上到处都是蘑菇。
9 celibate 3cKyS     
adj.独身的，独身主义的；n.独身者
参考例句：
  • He had defended the institution of a celibate priesthood.他捍卫了独身牧师制度。
  • The instinct of the celibate warned him to hold back.单身汉的本能告诫他回头是岸。

本文本内容来源于互联网抓取和网友提交，仅供参考，部分栏目没有内容，如果您有更合适的内容，欢迎 点击提交 分享给大家。