SSS 2008-11-06
时间：2019-01-08 作者：英语课 分类：Scientific American(十一)月
This is Scientific American's 60-Second Science. I'm Karen Hopkin. This will just take a minute.
Why bother with sex? It’s a question that’s bugged 1 biologists since they first noticed that some critters do it and some don’t. The answer they’ve come up with is that sex generates genetic 2 diversity, which could allow a species to better adapt to changing environments. That’s because sex mixes together the genes 3 from mom and dad. And, like shuffling 4 a deck of cards and dealing 5 new hands, sometimes the kids will get a better combination of genes than their parents had.
So how do species that reproduce by cloning weather change? It turns out not all clones are alike. Scientists from Melbourne were studying a kind of mite 6 that reproduces asexually. In the process, sometimes rare mutations occur, so a clone might be a little different from its parent, and from the rest of the population.
What the scientists found is that sometimes these rare mutants are favored by natural selection. Maybe they’re a little better at hiding from predators 7. So they leave behind more offspring, and eventually come to dominate the population. When circumstances change, another rare mutant might gain favor, results that appear in the current issue of the Proceedings 8 of the National Academy of Sciences. So sex isn’t necessary, as long as you’re willing to back somebody different when it’s time for a change.
Thanks for the minute for Scientific American's 60-Second Science. I'm Karen Hopkin.
- The police have bugged his office. 警察在他的办公室装了窃听器。 来自《简明英汉词典》
- He had bugged off before I had a chance to get a word in. 我还没来得及讲话，他已经走了。 来自《简明英汉词典》
- 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。
- You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
- Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪
- This store has an excellent reputation for fair dealing.该商店因买卖公道而享有极高的声誉。
- His fair dealing earned our confidence.他的诚实的行为获得我们的信任。
- birds and their earthbound predators 鸟和地面上捕食它们的动物
- The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》
- He was released on bail pending committal proceedings. 他交保获释正在候审。
- to initiate legal proceedings against sb 对某人提起诉讼