SSS 2012-02-23
时间：2018-12-24 作者：英语课 分类：Scientific American(二)月
英语课
This is Scientific American 60 second Science, I'm Sophie Bushwick, got a minute
In the lab, female rodents 1 sometimes terminate their pregnancies 2 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 evolutionary 3 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 hormones 4 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 progeny 5. 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
1 rodents
n.啮齿目动物( rodent的名词复数 )
- 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
怀孕，妊娠( pregnancy的名词复数 )
- 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
adj.进化的；演化的，演变的；[生]进化论的
- 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。