SSS 2012-01-24
时间：2018-12-24 作者：英语课 分类：Scientific American(一)月
英语课
This is Scientific American Sixty Seconds Science, I'm Sophie Bushwick, got a minute?
When Mexican tetra fish moved into darker caves long ago, they evolved to deal with the dark by becoming albino and going blind. A new research shows that the changes various cavefish populations went through occurred repeatedly. A massive textbook example of convergent 1 revolution. The studys in the journal BioMed Central Evolutionary 2 Biology.
To determine how the dark-dwelling fish evolved their sightlessness, researchers tested the DNA 3 of 11 Mexican cavefish populations; they compared the genes 4 with those of the tetra populations that lived out in the light. Originally researches had believed that all of the cave populations were descended 5 from a single group of tetra fish that went underground and then went blind. But the cavefish genes told a different story: the 11 populations had five separate evolutionary origins, with different groups independently experiencing and selecting an eyeless mutation 6. Although the surfacing cave-dwelling fish frequently mix, interbreeding has not eradicated 7 cavefish blindness, which means that evolution is actively 8 selecting blindness, perhaps because investing bodily resources in sight is a waste of energy in the dark.
Thanks for the minute for Scientific American Sixty Seconds Science, I'm Sophie Bushwick.
1 convergent
adj.会聚的
- A curved-inwards wall has a convergent effect on wall spray.凹型壁面对碰壁喷雾有聚集作用。
- If a sequence is not convergent,it is divergent.如果一个序列不收敛，我们称它发散。
2 evolutionary
adj.进化的；演化的，演变的；[生]进化论的
- 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。
3 DNA
(缩)deoxyribonucleic acid 脱氧核糖核酸
- DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
- Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
4 genes
n.基因( gene的名词复数 )
- You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
- Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪
5 descended
a.为...后裔的，出身于...的
- A mood of melancholy descended on us. 一种悲伤的情绪袭上我们的心头。
- The path descended the hill in a series of zigzags. 小路呈连续的之字形顺着山坡蜿蜒而下。
6 mutation
n.变化，变异，转变
- People who have this mutation need less sleep than others.有这种突变的人需要的睡眠比其他人少。
- So far the discussion has centered entirely around mutation in the strict sense.到目前为止，严格来讲，讨论完全集中于围绕突变问题上。
7 eradicated
画着根的
- Polio has been virtually eradicated in Brazil. 在巴西脊髓灰质炎实际上已经根除。
- The disease has been eradicated from the world. 这种疾病已在全世界得到根除。