SSS 2008-12-08
时间：2019-01-08 作者：英语课 分类：Scientific American(十二)月
This is Scientific American's 60-Second Science. I'm Karen Hopkin. This will just take a minute.
Animals that live in cold climates tend to have stubby limbs—shorter arms and legs—even smaller ears and tails. Picture a penguin 1 and you’ll see what I mean. Biologists have long assumed that these stumpy appendages 2 are an evolutionary 3 adaptation. Shorter extremities 4 minimize heat loss, so animals that are more compact are better suited to the cold.
But scientists from Ohio say that temperature may have a more direct effect on the length of an animal’s limbs. Because they find that turning up the heat helps cartilage grow—results that were published in the Proceedings 5 of the National Academy of Sciences.
The researchers raised mice at several different temperatures, and they confirmed that those kept at a balmy 80 degrees were longer limbed than those who lived at a more chill 45. But how does a little heat make mice more leggy? The answer, they find, lies in the cartilage. Long bones grow from the cartilage found at either end. And the warmer it is, the more that cartilage grows, even when it’s just sitting in a test tube. Which I guess means it’s possible that the dog days of summer lead to longer-legged dogs.
Thanks for the minute for Scientific American's 60-Second Science. I'm Karen Hopkin.
- The penguin is a flightless bird.企鹅是一种不会飞的鸟。
- He walked with an awkward gait like a penguin.他走路的步子难看得就像企鹅。
- The 11th segment carries a pair of segmented appendages, the cerci. 第十一节有一对分节的附肢，即尾须。 来自辞典例句
- Paired appendages, with one on each side of the body, are common in many animals. 很多动物身上有成对的附肢，一侧一个，这是很普遍的现象。 来自辞典例句
- Life has its own evolutionary process.生命有其自身的进化过程。
- These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。
- She was most noticeable, I thought, in respect of her extremities. 我觉得她那副穷极可怜的样子实在太惹人注目。 来自辞典例句
- Winters may be quite cool at the northwestern extremities. 西北边区的冬天也可能会相当凉。 来自辞典例句
- 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