【英语时差8,16】进化在行动

Evolution In Action Although rainforests cover less than two percent of Earth’s surface, they are home to more than half of all plant and animal species. How did rainforestsevolve so much more diversity than other parts of the globe? For starters, tropical species have had longer to evolve without extreme challenge from things like glaciers¹. Instead of destroying rainforests, climate changes like the ice ages usually just cause them to shrink. As a matter of fact, this periodic shrinkage might actually help generate more new species than it kills off.This is how it happens. When a rainforest shrinks, it sometimes fragments into isolated² rainforest pockets. These pockets can stay separated long enough for the isolated plants and animals to begin developing into different species from their cousins next door. When the pockets grow back to form a single forest again, the forest can have twice the number of species that it started with. Scientists working in the Daintree and Atherton Tableland rainforests of Australia have uncovered strong evidence for this. These rainforests are connected now, but during ice ages they were separated by a dry area. The scientists studied the genes³ of birds and lizards⁵ living on opposite sides of this area. Almost all the bird species showed a significant amount of genetic⁶ difference. What’s more, scientists found that the genes of one lizard⁴ species–the prickly skink–were so different that these skink are well on their way to becoming two separate species. We usually think of climate disasters like ice ages as bad news for life everywhere. In rainforests however, they can be an engine which, over time, enriches the web of life on Earth.

1 glaciers   

冰河，冰川( glacier的名词复数 )

参考例句：

• Glaciers gouged out valleys from the hills. 冰川把丘陵地带冲出一条条山谷。
• It has ice and snow glaciers, rainforests and beautiful mountains. 既有冰川，又有雨林和秀丽的山峰。 来自英语晨读30分（高一）

2 isolated   

adj.与世隔绝的

参考例句：

• His bad behaviour was just an isolated incident. 他的不良行为只是个别事件。
• Patients with the disease should be isolated. 这种病的患者应予以隔离。

3 genes   

n.基因( gene的名词复数 )

参考例句：

• 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

4 lizard   

n.蜥蜴，壁虎

参考例句：

• A chameleon is a kind of lizard.变色龙是一种蜥蜴。
• The lizard darted out its tongue at the insect.蜥蜴伸出舌头去吃小昆虫。

5 lizards   

n.蜥蜴( lizard的名词复数 )

参考例句：

• Nothing lives in Pompeii except crickets and beetles and lizards. 在庞培城里除了蟋蟀、甲壳虫和蜥蜴外，没有别的生物。 来自辞典例句
• Can lizards reproduce their tails? 蜥蜴的尾巴断了以后能再生吗？ 来自辞典例句

6 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。