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(单词翻译:双击或拖选)
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 bugged1 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 genetic2 diversity, which could allow a species to better adapt to changing environments. That’s because sex mixes together the genes3 from mom and dad. And, like shuffling4 a deck of cards and dealing5 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 mite6 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 predators7. 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 Proceedings8 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.
1 bugged | |
vt.在…装窃听器(bug的过去式与过去分词形式) | |
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2 genetic | |
adj.遗传的,遗传学的 | |
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3 genes | |
n.基因( gene的名词复数 ) | |
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4 shuffling | |
adj. 慢慢移动的, 滑移的 动词shuffle的现在分词形式 | |
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5 dealing | |
n.经商方法,待人态度 | |
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6 mite | |
n.极小的东西;小铜币 | |
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7 predators | |
n.食肉动物( predator的名词复数 );奴役他人者(尤指在财务或性关系方面) | |
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8 proceedings | |
n.进程,过程,议程;诉讼(程序);公报 | |
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