时差N小时:巨型昆虫的进化与消亡(上)
日期:2017-05-22 17:55

(单词翻译:单击)

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Once upon a time, hundreds of millions of years ago, many insects were much larger than they are today.
很久以前,大约几亿年前,许多昆虫的体型要比现在的昆虫大得多f_Ld[Z9W@@!k^#4G.YY
Scientists have found fossilized remains of dragonflies with wingspans several feet in diameter.
科学家已经发现翼展直径长达几英尺的蜻蜓化石YPef(0[M,1!oN
Other insects were equally monstrous due largely to the abundance of oxygen in the atmosphere.
其它昆虫的体型也不可小觑,究其原因是因为当时的大气中氧气含量充足所致BM_kJP.;Wo8Yd

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Oxygen is the fuel that powers insects’ flight muscles. So the more oxygen in the atmosphere, the larger insects tend to grow.
氧气是昆虫锻炼飞行肌的动力来源lLR05Llh!avWXs0Xgkf。因此,大气中的氧气越充足,昆虫的体型就越庞大y.5=tT6fI]nmZ(4c(=Jk
Hundreds of millions of years ago, oxygen made up around 30% of the earth’s atmosphere, compared to about 20% today.
几亿年前,地球大气的含氧量高达30%,如今大气的含氧量只有20%Q2Rw&m.Gbr-1FtS5
But around 150 million years ago, even though oxygen saturated the atmosphere, giant insects began to disappear.
大约一亿五千万年前,虽然大气中的含氧量仍然趋于饱和,但巨型昆虫还是相继灭绝%kEMUmC~JVy9buuHs
Why? Scientists suspect it was due mainly to the evolution of insect-eating birds.
究竟是何原因?科学家怀疑主要原因可能是食虫鸟类的进化所致的Ffq24)ODS5*)c=7qT+nm
Bird like creatures existed earlier, but their ability to fly and maneuver was limited.
现在的鸟类与远古时期的鸟类相差无几,只是当时鸟类的飞行能力和控制力十分有限@1NAjZPg.7^;_
Their offspring eventually evolved smaller tails, specialized wing bones, and larger breast bones.
它们的后代最终进化成尾巴更小,胸骨更大,翼骨更加发达的鸟类@bK_m!VMQP

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