句间停顿:
  • 1S
  • 3S
  • 5S
语速: x 1.0
  • 速度0.8X
  • 速度1.0X
  • 速度1.2X
  • 速度1.5X
  • 速度1.8X
  • 速度2X
始终显示原文
欢迎使用 KMF 精听精研
坚持练习精听,反复听、吃透每个句子,能够快速 提升听力能力
开始精听
或按 「 空格」开始播放

段落1

This is Scientific American's 60-Second Science. I'm Karen Hopkin. This'll just take a minute.

点击显示原文

隐藏原文=

Most birds don't have penises.

点击显示原文

隐藏原文=

Good, I have your attention.

点击显示原文

隐藏原文=

Of course female birds don't have penises, but neither do most males.

点击显示原文

隐藏原文=

Now researchers have unraveled the genetics behind the disappearance of this anatomical apparatus.

点击显示原文

隐藏原文=

Their penetrating insights are in the journal Current Biology.

点击显示原文

隐藏原文=

Only 3 percent of avian species have males with obvious organs of intromission.

点击显示原文

隐藏原文=

Ducks and other water fowl are fairly well endowed.

点击显示原文

隐藏原文=

But most birds have just rudimentary gear, if anything at all.

点击显示原文

隐藏原文=

To get to the root of this penile puzzle, researchers compared the embryos of chickens and ducks.

点击显示原文

隐藏原文=

Both types of birds start to develop a member.

点击显示原文

隐藏原文=

But in chickens, this so-called "genital tubercle" shrinks before the little guys hatch.

点击显示原文

隐藏原文=

And it's because of a gene called Bmp4.

点击显示原文

隐藏原文=

Bmp4 basically tells cells to commit suicide.

点击显示原文

隐藏原文=

This form of cell death keeps birds from sprouting teeth.

点击显示原文

隐藏原文=

And in developing male chickens, it causes the phallus to regress.

点击显示原文

隐藏原文=

Why this happens is still a mystery.

点击显示原文

隐藏原文=

It may allow female birds to be more selective about their mates.

点击显示原文

隐藏原文=

Because males with external equipment tend to impose it where they will.

点击显示原文

隐藏原文=

Whereas those without have to let the ladies rule the roost.

点击显示原文

隐藏原文=

Thanks for the minute, for Scientific American's 60-Second Science. I'm Karen Hopkin.

点击显示原文

隐藏原文=
[ < 空格 > ]
当前句 /
/
  • 段落1
  • 第 1 句
  • 第 2 句
  • 第 3 句
  • 第 4 句
  • 第 5 句
  • 第 6 句
  • 第 7 句
  • 第 8 句
  • 第 9 句
  • 第 10 句
  • 第 11 句
  • 第 12 句
  • 第 13 句
  • 第 14 句
  • 第 15 句
  • 第 16 句
  • 第 17 句
  • 第 18 句
  • 第 19 句
  • 第 20 句
  • 第 21 句

+ 创建收藏夹
保存 取消