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北师大版高中英语新教材(选择性必修第一册)课文 （Unit 3 | LESSON 1)

Lesson 1 The Sixth Extinction第一课 第六次灭绝

Extinctions, where entire species are wiped out, are not unusual in our Earth’s history. In

fact, over 90 percent of all species that ever lived are now extinct. In the last 500 million years,

there have been five times when life on Earth has almost ended. These include the third mass

extinction, known as the “Great Dying”, which killed 90% to 96% of all species. And the fifth

event, which

occurred 66 million years ago, caused the death of the dinosaurs. The reasons for

extinctions are varied. According to scientists, they include volcanic eruptions, asteroids

hitting the Earth from space, changes in sea levels, the decrease of the oxygen content of the

sea and global warming. Many scientists say we are now entering the Earth’s sixth mass

extinction. This time, human activity will be to blame.

物种灭绝，即某个物种的完全消失，在地球的历史上并不罕见。事实上，曾经存在的物种中90%

以上现在都已经灭绝。在过去的五亿年中，地球上出现过五次生物几乎全部灭绝的情况。这其中包括称

为“大灭绝”的第三次灭绝，期间90%至96%的物种灭亡。6600万年前发生的第五次灭绝导致了恐

龙的灭亡。灭绝的原因各不相同，科学家认为原因包括火山爆发、小行星从太空撞击地球、海平面变化、

海洋氧含量下降和全球变暖。许多科学家认为地球的第六次大灭绝即将来临，这一次，人类活动是主要

原因。

Although it is not unusual for species to die out naturally, the rate at which this is now

happening is cause for concern. A 2015 study by scientists who were based at Brown

University and Duke University in the US, looked at how quickly species die out due to natural

causes, that is, the

“background extinction rate”. They found that human activity is causing species to die

out 1,000 times faster than normal. There is a long list of reasons why so many species are

dying out: air and water pollution, forests being destroyed, factory farming and overfishing. It

is clear that human activity has negatively affected all other species on Earth, including

animals and plants.

虽然物种的自然灭绝并不罕见，但现在灭绝的速度让人担忧。2015年在美国布朗大学和杜克大学

的科学家进行的一项研究，调查了物种自然状态下灭亡的速度，即“背景灭绝率”。他们发现人类活动

导致物种灭亡的速度比正常情况快1000倍。这么多物种正在消亡的原因有很多：空气和水污染、森林

被毁、工厂化畜牧和过度捕捞。显然，人类活动对地球上所有

其他物种产生了负面影响，包括动物和植物。

If a sixth mass extinction occurs, scientists who have studied the issue believe that up to

three quarters of all species on Earth could die out. Of course, as we humans depend on so

many species for our survival, we would also be at risk of dying out. Our world and our lives

depend on the balance in nature between animals and plants. Without forests, we would have