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  • 大规模灭绝

    What you will learn
    ::你会学到什么

    • How human actions are driving the sixth mass extinction
      ::人类行动如何推动第六次大规模灭绝
    • Causes and effects of extinction
      ::原因及灭绝的影响
    • What can be done to protect
      ::B. 能够采取什么行动来保护

    The Philippine Eagle, critically endangered, illustrating biodiversity loss and conservation efforts.

    This is one of the most powerful birds in the world. Could it go extinct?
    ::这是世界上最强大的鸟类之一 它会灭绝吗?

    The Philippine Eagle, also known as the Monkey-eating Eagle, is among the rarest, largest, and most powerful in the world. It is critically endangered, mainly due to massive loss of habitat due to deforestation in most of its range. Killing a Philippine Eagle is punishable under Philippine law by twelve years in jail and heavy fines.
    ::菲律宾鹰(又称食猴鹰)是世界上最稀有、最大和最强大的鹰之一。 它受到严重威胁,主要原因是大部分森林砍伐导致大量生境丧失。 根据菲律宾法律,杀害菲律宾鹰将被判处12年监禁和重罚。

    Human Actions and the Sixth Mass Extinction
    ::人类行动和第六大规模灭绝

    Over 99 percent of all that ever lived on Earth have gone extinct. Five mass extinctions are recorded in the . They were caused by major geologic and climatic events. Evidence shows that a sixth mass extinction is occurring now. Unlike previous mass extinctions, the sixth extinction is due to human actions.
    ::地球上超过99%的人已经灭绝了。有五种大规模灭绝记录在其中。它们是由重大的地质和气候事件造成的。证据表明第六种大规模灭绝现在正在发生。与以前的大规模灭绝不同,第六种大规模灭绝是由人类行为造成的。

    Some scientists consider the sixth extinction to have begun with early hominids during the Pleistocene. They are blamed for over-killing big mammals such as mammoths. Since then, human actions have had an ever greater impact on other species. The present rate of extinction is between 100 and 100,000 species per year. In 100 years, we could lose more than half of Earth’s remaining species.
    ::一些科学家认为第六次灭绝始于普莱斯丁(Pleistocene)的早期人类。 他们被指责为大哺乳动物(如猛象)超杀。 从那时起,人类行为对其他物种的影响就越来越大。 目前,每年的灭绝速度在100到10万种之间。 在100年中,我们可能会损失地球所剩物种的一半以上。

     

     

    Causes of Extinction
    ::灭绝的原因

    The single biggest cause of extinction today is habitat loss . , forestry, mining, and urbanization have disturbed or destroyed more than half of Earth’s land area. In the U.S., for example, more than 99 percent of tall-grass prairies have been lost. Other causes of extinction today include:
    ::今天,灭绝最大的一个原因就是生境的丧失。 林业、采矿业和城市化已经扰乱或摧毁了地球一半以上的陆地面积。 比如,在美国,99%以上的高草原已经丧失。 今天,灭绝的其他原因包括:

    • Exotic species introduced by humans into new habitats. They may carry disease, prey on native species, and disrupt food webs . Often, they can out-compete native species because they lack local predators . An example is described in the Figure .
      ::人类引入新生境的外来物种可能携带疾病,食用本地物种,扰乱食物网。 通常,它们能够超越本地物种,因为它们缺乏本地食肉动物。 图中描述了一个例子。
    • Over-harvesting of , trees, and other organisms . This threatens their survival and the survival of species that depend on them.
      ::过度收获树木和其他生物,威胁着它们的生存和依赖它们生存的物种的生存。
    • Global climate change, largely due to the burning of fossil fuels . This is raising Earth’s air and ocean temperatures. It is also raising sea levels. These changes threaten many species.
      ::全球气候变化主要是由于化石燃料的燃烧造成的。 这正在提高地球的空气和海洋温度。 它还在提高海平面。 这些变化威胁着许多物种。
    • Pollution, which adds chemicals, heat, and noise to the environment beyond its capacity to absorb them. This causes widespread harm to organisms.
      ::污染给环境增加了化学品、热量和噪音,使环境无法吸收这些化学品、热量和噪音,对生物体造成广泛伤害。
    • Human overpopulation, which is crowding out other species. It also makes all the other causes of extinction worse.
      ::人类人口过剩,排挤了其他物种,也使所有其他灭绝原因更加严重。
    A close-up of a brown tree snake, a species impacting local ecosystems in Guam.
    The Brown tree snakes "hitch-hiked" from their native Australia on ships and planes to Pacific islands such as Guam. Lacking local island predators, this exotic species of snakes multiplied quickly. They have already caused the extinction of many birds and mammals they preyed upon in their new island ecosystems.

    Effects of Extinction
    ::灭绝的影响

    The results of a study released in the summer of 2011 have shown that the decline in the numbers of large predators like sharks, lions, and wolves is disrupting Earth's in all kinds of unusual ways. The study, conducted by scientists from 22 different institutions in six countries, confirmed the sixth mass extinction. The study states that this mass extinction differs from previous ones because it is entirely driven by human activity through changes in land use, climate, pollution, hunting, fishing, and poaching. The effects of the loss of these large predators can be seen in the oceans and on land.
    ::2011年夏季公布的一项研究结果显示,鲨鱼、狮子和狼等大型掠食动物数量的减少以各种不同方式扰乱了地球。这项研究由来自六个国家的22个不同机构的科学家进行,证实了第六次大规模灭绝。研究指出,这种大规模灭绝不同于以往的大规模灭绝,因为它完全受人类活动驱动,改变土地使用、气候、污染、狩猎、捕鱼和偷猎。这些大型捕食动物的丧失造成的影响可以在海洋和陆地上看到。

    • Fewer cougars in the western US state of Utah led to an explosion in the deer . The deer ate more vegetation, which altered the path of local streams and lowered overall biodiversity.
      ::美国西部犹他州的幼鲸数量较少,导致鹿的爆炸。 鹿吃了更多的植物,改变了当地溪流的路径,降低了总体生物多样性。
    • In Africa, where lions and leopards are being lost to poachers, there is a surge in the number of olive baboons, who are transferring intestinal parasites to humans living nearby.
      ::在非洲,偷猎者正在失去狮子和豹子,而橄榄兔子的数量激增,他们正在把肠寄生虫转移给附近的人类。
    • In the oceans, industrial whaling led to a change in the diets of killer whales, who eat more sea lions, seals, and otters, and have dramatically lowered the population counts of those species.
      ::在海洋中,工业捕鲸导致虎鲸饮食的改变,虎鲸食用更多的海狮、海豹和水燕,大大降低了这些物种的人口数量。

    The study concludes that the loss of big predators has likely driven many of the pandemics, population collapses, and ecosystem shifts the Earth has seen in recent centuries. 
    ::研究结论认为,大掠食动物的消失很可能已导致许多流行病、人口崩溃和地球近几个世纪生态系统的变化。

    Disappearing Frogs
    ::消失的青蛙

    Around the world, frogs are declining at an alarming rate due to threats like pollution, disease, and climate change. Frogs bridge the gap between and land habitats, making them the first indicators of ecosystem changes. 
    ::由于污染、疾病和气候变化等威胁,青蛙正在以惊人的速度在世界各地以惊人的速度下降。 青蛙弥合了陆地生境与陆地生境之间的差距,成为生态系统变化的第一个指标。

     

     

    Nonnative Species
    ::非本地物种

    Scoop a handful of critters out of the San Francisco Bay and you'll find many organisms from far away shores. Invasive kinds of mussels, fish, and more are choking out native species, challenging experts around the state to change the human behavior that brings them here.
    ::从旧金山湾挖出一小撮动物,你会发现来自远岸的许多生物。入侵性的贝类、鱼类和更多的生物正在窒息本地物种,挑战国家周围的专家改变人类行为,而人类行为却把他们带到这里来。

     

     

    How You Can Help Protect Biodiversity
    ::如何帮助保护生物多样性

    There are many steps you can take to help protect biodiversity. For example:
    ::你可以采取许多步骤来帮助保护生物多样性。例如:

    • Consume wisely. Reduce your consumption wherever possible. Re-use or recycle rather than throw out and buy new. When you do buy new, choose products that are energy efficient and durable.
      ::明智地消费。 尽可能减少消费。 重新使用或再循环, 而不是丢弃和购买新产品。 当你购买新产品时, 选择节能和耐久的产品 。
    • Avoid plastics. Plastics are made from petroleum and produce toxic waste.
      ::塑料用石油制成,产生有毒废物。
    • Go organic. Organically grown food is better for your health. It also protects the environment from pesticides and excessive nutrients in fertilizers.
      ::有机食品,有机食品对健康有益,还可以保护环境,免受杀虫剂和肥料中过度养分的影响。
    • Save energy. Unplug electronic equipment and turn off lights when not in use. Take mass transit instead of driving.
      ::节省能源, 解除电子设备插头, 不使用时关闭灯光, 使用公共交通, 而不是驾驶 。

    Lost Salmon
    ::丢失的鲑鱼

    Why is the salmon population of Northern California so important? Salmon do not only provide food for humans but also supply necessary nutrients for their ecosystems. The species in the most danger of extinction is the California coho salmon.
    ::为什么北加州的鲑鱼种群如此重要? 鲑鱼不仅为人类提供食物,而且为其生态系统提供必要的养分。 最濒临灭绝的物种是加利福尼亚可可鲑鱼。

     

     

    Summary
    ::摘要

    • Evidence shows that a sixth mass extinction is occurring. The single biggest cause is habitat loss caused by human actions.
      ::证据表明,第六次大规模灭绝正在发生,最大的一个原因是人类行为造成的生境损失。
    • There are many steps you can take to help protect biodiversity. For example, you can use less energy.
      ::您可以采取许多步骤来保护生物多样性。例如,您可以少用能源。

    Review
    ::回顾

    1. How is human overpopulation related to the sixth mass extinction?
      ::人类人口过剩与第六次大规模灭绝有何关系?
    2. Why might the brown tree snake or the Philippine Eagle serve as “poster species” for causes of the sixth mass extinction?
      ::为什么褐色树蛇或菲律宾鹰会成为第六次大规模灭绝的“后世物种”呢?
    3. Describe a hypothetical example showing how rising sea levels due to global warming might cause extinction.
      ::描述一个假设的例子,说明全球变暖造成的海平面上升如何可能导致灭绝。
    4. Create a poster that conveys simple tips for protecting biodiversity.
      ::创建海报,传达保护生物多样性的简单提示。