Listening to Birdsong
A male zebra finch(雀科鸣鸟) chirps(鸣) away to himself. Suddenly he notices a female bird nearby. He realizes he has an audience and immediately changes his song. Can the female tell the difference in his performance? According to a new study, the female zebra finch knows. And she prefers the special trills(啭音) he creates when he sings to her. A male zebra finch changes his song when singing to a female in ways that people can barely detect. But the female finch can tell the difference.
Scientists had noticed slight variations in the songs of male zebra finches based on whether they were singing alone or whether there was a female (and potential mate) nearby. With an audience, the males sped up the pace of their songs and controlled the notes they used.
For this study, researchers Sarah C. Woolley and Allison Doupe at the University of California, San Francisco decided to focus attention on the listening females, which have not been well studied in the past.
In the study, Woolley and Doupe set up a long cage with a sound speaker at each end. One broadcast the sound of a male zebra finch singing to himself, like someone singing in the shower. The other speaker broadcast a male performing for a female audience, as if he was giving a concert.
Female birds were placed between the two speakers. Some of the birds had mates, others didn't. The females shifted around a bit, and then most of them hopped over to sit beside just one speaker. All the birds that made a clear choice liked songs meant for a female audience, even if they'd never met the male.
Mated females also had a chance to listen to two different performance songs, one from an unknown male, and one from their mate. They spent more time listening to the concert version of their mates' songs. This suggests that after a while, females learn to recognize—and prefer—the songs of their mates.
Scientists then studied the brains of the females. They found certain areas of the brain perked up (活跃起来) when the birds listened to the concert songs. These brain areas may be involved in recognizing and evaluating the songs, and storing the memories of them.
This research deals with what's called directed communication, when the communicator, or sender, focuses the message for a specific audience. One example is the way moms speak to their babies. Mothers around the world use the same sort of high-pitched sing-song chatter(喋喋不休), and the babies respond best to those sounds. Songbirds are one of the only other species known to learn their communication, in this case their songs.
Which of the following is true about birdsongs?
A.Female zebra finches are too shy to sing before males.
B.Male zebra finches sing louder than females.
C.Female zebra finches like to listen to unknown males sing.
D.Male zebra finches change their songs to attract females.
第1题
有关血细胞发育成熟的一般规律,描述正确的是
A、细胞体积由小变大
B、核质比例由大到小
C、核染色质结构由紧密粗糙到疏松细致
D、核仁从无到有
E、肝、脾和淋巴结肿大
第4题
下列关于血细胞发育过程的一般规律描述正确的是
A.细胞体积由小变大
B.核浆比例由大变小
C.核染色质结构由紧密粗糙到疏松细致
D.核仁由无到有
E.胞质颗粒从有到无
第5题
从原始细胞到成熟细胞,符合血细胞发育过程的一般规律的是
A、核仁由无到有
B、核质比例由大到小
C、胞质颗粒从有到无
D、细胞体积由小变大
E、核染色质结构紧密粗糙到疏松细致
第6题
血细胞发育的一般规律描述正确的是
A.细胞体积由小变大
B.核浆比例由小到大
C.核染色质结构由紧密粗糙到疏松细致
D.核仁从有到无
E.胞质中颗粒从少到多
第7题
下列血细胞发育过程的一般规律描述正确的是
A、细胞体积由小变大
B、核染色质结构由紧密粗糙到疏松细致
C、核仁由无到有
D、核浆比例由大到小
E、胞质颗粒从有到无
第8题
血细胞发育的一般过程描述,正确的是
A、细胞体积从小到大
B、核质比例由大到小
C、核染色质结构由紧密粗糙到疏松细致
D、核仁从无到有
E、胞质颗粒从有到无
第9题
下列血细胞发育过程的一般规律描述正确的是
A.细胞体积由小变大
B.核浆比例由小到大
C.核仁由无到有
D.核染色质结构由紧密粗糙到疏松细致
E.胞质颗粒从少到多
第10题
血细胞从原始到成熟,下列哪项不符合血细胞发育的一般规律
A.细胞由大到小
B.核质比从小到大
C.核染色质结构由细致到粗糙
D.核仁从显著可见到无
E.胞质颗粒从无到有
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