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SSS 2012-02-23

时间:2012-03-19 06:17来源:互联网 提供网友:gmeng   字体: [ ]
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 This is Scientific American 60 second Science, I'm Sophie Bushwick, got a minute

 
In the lab, female rodents1 sometimes terminate their pregnancies2 after being exposed to new males. It’s called the Bruce effect, for researcher Hilda Bruce. Now a study in the journal Science finds that the Bruce effect occurs in the wild, and likely ups evolutionary3 fitness.
 
To discover whether the Bruce effect is a naturally occurring adaptive strategy, researchers from the University of Michigan observed a wild population of gelada monkeys. They measured hormones4 in the animals’ feces to identify pregnant females and their conception dates.
 
Gelada monkeys live in small groups, with several females and a single male. When a rival displaces the male in a gelada family, he frequently kills his predecessor’s progeny5. And the females know it. The researchers found that females impregnated by the old male terminate 80 percent of their pregnancies after the new male takes over.
 
Those females were quicker to conceive again with the new male than were females who hadn’t been pregnant. Rather than producing offspring at risk of death, females subject to the Bruce effect invest in new progeny—with a better chance of survival.
 
Thanks for the minute for scientific American 60 second science, I'm Sophie Bushwick

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1 rodents 1ff5f0f12f2930e77fb620b1471a2124     
n.啮齿目动物( rodent的名词复数 )
参考例句:
  • Rodents carry diseases and are generally regarded as pests. 啮齿目动物传播疾病,常被当作害虫对待。 来自《简明英汉词典》
  • Some wild rodents in Africa also harbor the virus. 在非洲,有些野生啮齿动物也是储毒者。 来自辞典例句
2 pregnancies 2fedeb45162c233ee9e28d81888a2d2c     
怀孕,妊娠( pregnancy的名词复数 )
参考例句:
  • Since the wartime population needed replenishment, pregnancies were a good sign. 最后一桩倒不失为好现象,战时人口正该补充。
  • She's had three pregnancies in four years. 她在四年中怀孕叁次。
3 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。
4 hormones hormones     
n. 荷尔蒙,激素 名词hormone的复数形式
参考例句:
  • This hormone interacts closely with other hormones in the body. 这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。
  • The adrenals produce a large per cent of a man's sex hormones. 肾上腺分泌人体的大部分性激素。
5 progeny ZB5yF     
n.后代,子孙;结果
参考例句:
  • His numerous progeny are scattered all over the country.他为数众多的后代散布在全国各地。
  • He was surrounded by his numerous progeny.众多的子孙簇拥着他。
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