【英语语言学习】原始人的母乳喂养

RENEE MONTAGNE, HOST:

 

Over the past few years, research has taught us a lot about Neanderthals, about their red hair and their blood type and their genome. And now we're learning about their breastfeeding practices. As NPR's Adam Cole reports, figuring out Neanderthals' nursing habits will help us understand our own evolution.

 

ADAM COLE, BYLINE¹: Manish Arora just had triplets, and he loves watching his newborns learn and grow. But sometimes his fatherly pride is expressed a bit scientifically.

 

MANISH ARORA: I've already started recording² a lot of data on my babies.

 

COLE: Specifically, he's interested in the development of their teeth. That's because Arora studies tooth chemistry at the Icahn School of Medicine in New York City.

 

ARORA: Teeth develop in a very interesting and very systematic³ manner.

 

COLE: Arora's triplets began to form teeth in the womb, creating a new layer of enamel⁴ and dentine each day.

 

ARORA: You can almost visualize⁵ tooth development in terms of growth rings that you would see in a tree.

 

COLE: Like tree rings, those tooth layers mark the passage of time. A very prominent line marks the stressful moment of birth, and the composition of those layers holds clues about the baby's nutrition and development. But there's one important piece missing.

 

ARORA: There wasn't a useful, objective biomarker for breastfeeding.

 

COLE: Scientists, whether they study human development or study human evolution, wanted some sort of signal written in the enamel that said: Here's when the baby stopped nursing. So Arora set out to find one. He meticulously⁶ recorded the breast-feeding habits of women and their babies. Years later, when the children started losing their baby teeth, Arora was there to collect them.

 

He and his colleagues took thin slices of the teeth and blasted them with lasers to vaporize chemicals for analysis. They started to notice a pattern in the distribution of the element barium.

 

ARORA: During the period of breast-feeding, the barium levels in teeth were higher as we had predicted. And at weaning, the levels of barium in teeth started to drop.

 

COLE: Barium is an elemental cousin of calcium⁷, and over a lifetime, it accumulates in our bones. That barium ends up in breast milk, and eventually in baby's teeth. Arora had his marker. He could look at a tooth and identify the time of weaning. His colleague, Tanya Smith, who studies human evolution at Harvard, knew just the tooth to analyze⁸ first.

 

TANYA SMITH: This tooth, it's a first molar tooth from a Neanderthal from a site in Belgium called Scladina.

 

COLE: The tooth is 100,000 years old, but it's perfectly⁹ preserved. By analyzing¹⁰ barium levels in the molar, researchers found that its owner started weaning at about 7 months, and then transitioned to a mixed diet. The results were published in the journal Nature. The study is a first step towards figuring out an odd difference between humans and their closest relatives, the great apes.

 

Chimpanzees and gorillas¹¹ stop nursing after four years. Humans living in preindustrial societies stop much sooner. So the big evolutionary¹² question is this...

 

SMITH: When, in our past, do we see this shift?

 

COLE: Smith hopes that analyzing more fossilized teeth will provide the answer. The evolution of early weaning was important. Shorting nursing times would have given mothers the freedom to reproduce more frequently and gather food for the group. As for Arora, he can't wait to study the teeth of his own kids. His wife has signed off on the idea.

 

ARORA: She's only concerned that the teeth be allowed to shed naturally, and I don't, you know, nudge the process along.

 

COLE: Adam Cole, NPR News.

1 byline   

n.署名；v.署名

参考例句：

• His byline was absent as well.他的署名也不见了。
• We wish to thank the author of this article which carries no byline.我们要感谢这篇文章的那位没有署名的作者。

2 recording   

n.录音，记录

参考例句：

• How long will the recording of the song take?录下这首歌得花多少时间？
• I want to play you a recording of the rehearsal.我想给你放一下彩排的录像。

3 systematic   

adj.有系统的，有计划的，有方法的

参考例句：

• The way he works isn't very systematic.他的工作不是很有条理。
• The teacher made a systematic work of teaching.这个教师进行系统的教学工作。

4 enamel   

n.珐琅，搪瓷，瓷釉；(牙齿的)珐琅质

参考例句：

• I chipped the enamel on my front tooth when I fell over.我跌倒时门牙的珐琅质碰碎了。
• He collected coloured enamel bowls from Yugoslavia.他藏有来自南斯拉夫的彩色搪瓷碗。

5 visualize   

vt.使看得见，使具体化，想象，设想

参考例句：

• I remember meeting the man before but I can't visualize him.我记得以前见过那个人，但他的样子我想不起来了。
• She couldn't visualize flying through space.她无法想像在太空中飞行的景象。

6 meticulously   

adv.过细地，异常细致地；无微不至；精心

参考例句：

• The hammer's silvery head was etched with holy runs and its haft was meticulously wrapped in blue leather. 锤子头是纯银制成的，雕刻着神圣符文，而握柄则被精心地包裹在蓝色的皮革中。 来自辞典例句
• She is always meticulously accurate in punctuation and spelling. 她的标点和拼写总是非常精确。 来自辞典例句

7 calcium   

n.钙(化学符号Ca)

参考例句：

• We need calcium to make bones.我们需要钙来壮骨。
• Calcium is found most abundantly in milk.奶含钙最丰富。

8 analyze   

vt.分析，解析 (=analyse)

参考例句：

• We should analyze the cause and effect of this event.我们应该分析这场事变的因果。
• The teacher tried to analyze the cause of our failure.老师设法分析我们失败的原因。

9 perfectly   

adv.完美地，无可非议地，彻底地

参考例句：

• The witnesses were each perfectly certain of what they said.证人们个个对自己所说的话十分肯定。
• Everything that we're doing is all perfectly above board.我们做的每件事情都是光明正大的。

10 analyzing   

v.分析；分析( analyze的现在分词 )；分解；解释；对…进行心理分析n.分析

参考例句：

• Analyzing the date of some socialist countries presents even greater problem s. 分析某些社会主义国家的统计数据，暴露出的问题甚至更大。 来自辞典例句
• He undoubtedly was not far off the mark in analyzing its predictions. 当然，他对其预测所作的分析倒也八九不离十。 来自辞典例句

11 gorillas   

n.大猩猩( gorilla的名词复数 )；暴徒，打手

参考例句：

• the similitude between humans and gorillas 人类和大猩猩的相像
• Each family of gorillas is led by a great silverbacked patriarch. 每个大星星家族都由一个魁梧的、长着银色被毛的族长带领着。 来自《简明英汉词典》

12 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• 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。