SSS 2009-07-08
时间：2019-01-04 作者：英语课 分类：Scientific American(七)月
This is Scientific American's 60-second Science. I'm Cynthia Graber, this will just take a minute.
Sex might seem like one of those little gifts from evolution. But it’s pretty inefficient 1 from an evolutionary 2 perspective. It’d be much easier to reproduce if you could do away with finding the right member of the opposite sex to help you create the next generation. So why did evolution come up with sex?Biologists have hypothesized that one driving force might have been parasites 4. Now scientists have had a chance to test that theory. Asexual reproduction leads to clones. Being genetically 6 identical, clones are also weak in the same ways, and thus more likely to all succumb 7 to a parasite 3. But sex keeps shuffling 8 the genetic 5 deck.
Well, there’s a snail 9 common in New Zealand lakes that does both—some populations have sex and some reproduce asexually. So researchers spent 10 years monitoring the two populations, and the number of parasites living off both groups. As expected, cloned snails 10 that were plentiful 11 at the beginning of the study suffered big losses as they became infected with parasites. But the sexual snail populations remained stable, results published in the journal American Naturalist 12. So, next time you’re feeling sexy, thank a parasite.
This is Scientific American's 60-second Science. I'm Cynthia Graber.
- The inefficient operation cost the firm a lot of money.低效率的运作使该公司损失了许多钱。
- Their communication systems are inefficient in the extreme.他们的通讯系统效率非常差。
- 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。
- The lazy man was a parasite on his family.那懒汉是家里的寄生虫。
- I don't want to be a parasite.I must earn my own way in life.我不想做寄生虫，我要自己养活自己。
- 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。
- 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。
- All the bees in the colony are genetically related. 同一群体的蜜蜂都有亲缘关系。
- Genetically modified foods have already arrived on American dinner tables. 经基因改造加工过的食物已端上了美国人的餐桌。 来自英汉非文学 - 生命科学 - 基因与食物
- They will never succumb to the enemies.他们决不向敌人屈服。
- Will business leaders succumb to these ideas?商业领袖们会被这些观点折服吗？
- Snail is a small plant-eating creature with a soft body.蜗牛是一种软体草食动物。
- Time moved at a snail's pace before the holidays.放假前的时间过得很慢。
- I think I'll try the snails for lunch—I'm feeling adventurous today. 我想我午餐要尝一下蜗牛——我今天很想冒险。 来自《简明英汉词典》
- Most snails have shells on their backs. 大多数蜗牛背上有壳。 来自《简明英汉词典》
- Their family has a plentiful harvest this year.他们家今年又丰收了。
- Rainfall is plentiful in the area.这个地区雨量充足。
- He was a printer by trade and naturalist by avocation.他从事印刷业，同时是个博物学爱好者。
- The naturalist told us many stories about birds.博物学家给我们讲述了许多有关鸟儿的故事。