选择城市
新东方网为大家带来2020托福听力练习：近亲繁殖的鸣禽易走调（下载），希望对大家有所帮助!更多内容请随时关注新东方网!
Just like humans have to learn to talk, songbirds aren't just born singing—they have to learn to carry a tune. "So in the beginning they just babble." Raissa de Boer, a behavioral ecologist at the University of Antwerp in Belgium. "And they learn from a tutor, so they need an example song in order to learn it."
She says the example song might come from the chick's father. And over time, the baby bird tweaks that tweet, to make it its own. "And then it takes almost a year until they're fully adult, until the next spring, for the final song to come out."
De Boer and her colleagues investigated that song-learning process in canaries, using two groups of baby birds: the first consisted of inbred birds, whose parents were siblings; the second had parents that were unrelated. And the researchers found that the songs of inbred birds and those of the other, outbred birds sound... pretty similar to the human ear. "I cannot tell the difference."
But computer analysis revealed that the inbred birds sang notes at slightly different pitches—and with tones that were not quite as pure. "So basically they sang out of tune, in comparison to outbred birds." The results appear in the Proceedings of the Royal Society B.
And even though our untrained ears have a hard time telling the tones apart, female canaries seemed to notice. They tended to lay smaller eggs, and fewer of them, when they mated with inbred birds as opposed to the better songsters. Suggesting that the quality of a songbird's genes may be revealed in its tunes.
翻译见下页
就像人类要学习说话一样，鸣禽也不是天生就会唱歌，它们也要学习唱歌不走调。“一开始它们只是呀呀学语。”蕾伊莎·德·波尔是比利时安特卫普大学行耿生态学家。她说，“它们跟随导师学习，所以它们在学习时需要一首典型歌曲。”
她表示，典型歌曲可能来自于雏鸟的父亲。随着时间的推移，雏鸟不断调整这种叫声，然后演变成它自己的叫声。“大概需要一年的时间，到雏鸟成年、到下一个春天来临的时候，最终的歌曲才会成形。”
德·波尔和她的同事用两组雏鸟对金丝雀学习歌曲的过程进行了研究：第一组是近亲繁殖生出的雏鸟，它们的父母是兄弟姐妹;第二组雏鸟的父母则没有任何关系。研究人员发现，人耳听起来，近亲繁殖鸟儿和非近亲繁殖鸟儿的歌声非常类似。“我不能分辨两者的区别。”
但是电脑分析显示，近亲生鸟儿唱出的歌曲音高不同，而且音调也不太纯。“所以基本上来说，与非近亲生鸟儿相比，近亲生鸟儿其实是跑调的。”这一研究结果发表在《皇家学会学报B》上。
虽然我们人类未经训练的耳朵很难区分这两种音调，但是看起来雌性金丝雀却能注意到两者的区别。当雌性金丝雀同近亲交配，而不是与更好的鸣禽交配时，它们产下的蛋个头较小，而且数量也会减少。这表明鸣禽的基因质量可能会显示在它们的歌声中。
重点讲解：
1. in order to 为了;以便;目的在于;
例句：They did this in order to head off the crisis.
他们这样做以防止发生危机。
2. consist of 由…组成;由…构成;
例句：A molecule of water consists of two atoms of hydrogen and one atom of oxygen.
水分子含有两个氢原子和一个氧原子。
3. in comparison to 与…相比;与…比较而言;
例句：In comparison to city life, life in the country is quiet and peaceful.
同城市生活相比，乡村生活既和平又宁静。
4. tell apart 区分;区别;辨别;
例句：Perhaps it is the almost universal use of flavourings that makes it so hard to tell the products apart.
或许是因为调料的使用几乎千篇一律才使得那些产品难以区分开。
5. as opposed to 而不是;
例句：Permission to be employed in this manner is issued to an individual, as opposed to an employer.
这种形式的工作许可是签发给申请人个人的，而不是给雇主的。
以上是新东方网为大家带来的2020托福听力练习：近亲繁殖的鸣禽易走调（下载），希望认真积极的备考，早日取得优异的成绩。更多内容请随时关注新东方网!
最新热文推荐：
更详细的内容请点击：2020软科世界一流学科排名发布
