英语听力文摘 English Digest 644 蟑螂实际上有用吗

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　　The natural History of the Cockroach¹, on this Moment of Science.

　　For certain species of cockroach, humans make the perfect roommates. Why do cockroaches like living in our houses? And what do they do when they’re not bugging³ us?

　　Although most us think of cockroaches as vermin, they do have a useful ecological⁴ role. Cockroaches are professional recyclers, chowing down just about anything, including dead plants and animals, and animal waste.

　　Their digestive systems are up to the task because they contain bacteria and protozoa that help convert the world’s waste into easily-absorbed nutrients⁵. In the wild, the waste of roaches nourishes growing plants, continuing the cycle.

　　Day In The Sun

　　300 million years ago, the Carboniferous period was the cockroaches’ day in the sun so to speak. The whole earth was swampy⁶ and hot, with new plants and animals appearing on the scene, creating lots of waste for roaches to recycle. As the earth’s climate changed, becoming colder and dryer⁷, cockroaches survived mainly in the tropics

　　A few hundred million years later, ships full of food and humans set out from the tropics, carrying clandestine⁸ cockroaches on board. Cockroaches disembarked in ports all over the world, searching for new homes. You might not have compared your house to a Carboniferous swamp, but the similarities wouldn’t escape a cockroach.

　　Cockroaches And Humans

　　There are lots of tasty crumbs⁹ littering the floor, a nice warm temperature year-round, and endless crannies to hide in. Despite these ideal living conditions, not all wandering cockroaches chose to shack¹⁰ up with humans. Of the 55 species of cockroach in the US, only 12 prefer human dwellings¹¹. The rest live outside, recycling without bugging us at all.

　　蟑螂实际上有用吗？

　　科学一刻为您揭秘蟑螂的自然发展历史。

　　对于某些品种的蟑螂来说，它们能够很好的融入人类的生活环境。为什么蟑螂会喜欢生活在我们房子里面呢？在烦扰我们之余，他们又都在做些什么?

　　尽管我们认为蟑螂是害虫，实际上他们对自然生态环境颇有益处。蟑螂是回收专家，能够吃下任何东西，包括死去的动植物以及动物的粪便。

　　它们的消化系统功能强大，含有某些细菌与原生动物能将世间废物变成极易吸收的营养物质。在野外，蟑螂的粪便给植物提供生长养分，让生态系统继续循环。

　　辉煌之时

　　可以这么说，3亿年以前的石炭纪是蟑螂的辉煌之时。那时的地球非常湿热，新生动植物的出现造成了大量的废弃物可供蟑螂进行回收利用。当地球的气候变得干冷之后，蟑螂只主要生活在热带地区。

　　几百万年以后，满载食物与人类的船只从热带出发，而蟑螂则偷偷摸摸地登上了船。蟑螂们登陆了全世界各个港口，寻找新家园。也许你不会将你的家与石炭纪的沼泽进行对比，但是蟑螂不会忽视其相似之处。

　　蟑螂与人类

　　人们房子里的地板上到处掉落着美味的面包屑，同时，常年保持温暖适宜的温度，而且有数不清的缝隙提供藏身之所。尽管生活条件理想，并不是所有蟑螂都选择与人们憩息在同一屋檐之下。在美国有55种蟑螂，其中只有12种喜欢与人类共处。其他种类都生活在室外，从不打扰我们，只是默默进行资源回收活动。

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