Lecture 2 环境生态
Wors Tips
habitat n.（动物的）栖息地，住处 migrate vi.迁移；随季节而移居
hummingbird 蜂鸟 hemisphere n.半球，地球的半球
nectar n.花蜜 theGulfofMexico 墨西哥湾
pollinate vt.给……传授花粉 pollen n.花粉
posearealthreatto 构成真正威胁
Listen to the following recording and answer questions 1-4.
1）A.major changes in the migratory patterns of hummingbirds
B.the adaptation of hummingbirds to urban environments
C.concern about the reduction of hummingbird habitat
D.the impact of ecotourism on hummingbird populations
2）A.Humming bird doesn’t need to feed when it migrates.
B.Humming bird beats its wings about 2 thousand times per minute.
C.Humming bird uses up almost all of its body fat when flying across the Gulf of Mexico.
D.Humming bird relies on nectar and insects and some flowers can only be pollinated by humming birds.
3）A.an increase in the ecotourism industry
B.an increase in the use of land to raise crops and cattle
C.a decrease in banding studies
D.a decrease in the distance traveled during migration
4）A.They have built a series of hummingbird feeding stations.
B.They have supported new laws that punish polluters of wildlife habitats.
C.They have replanted native flowers in once polluted areas.
D.They have learned to identify various hummingbird species.
听力原文
Now，we’ve been talking about the loss of animal habitat from housing developments，um…，growing cities — small habitat losses.But today I want to begin talking about what happens when habitat is reduced across a large area.There are，of course，animal species that require large areas of habitat，and some migrate over very long distances.So what’s the impact of habitat loss on those animals — animals that need large areas of habitat？
Well，I’ll use the humming birds as an example.
Now you know a humming bird is amazingly small，but even though it’s really tiny，it migrates over very long distances，travels up and down the western hemisphere — the Americas，back and forth between where it breeds in the summer and the warmer climates where it spends the winter.So we would say that this whole area over which it migrates is its habitat because on this long-distance journey，it needs to come down to feed and sleep every so often，right？
Well，the humming bird beats its wings — get this — about 3 thousand times per minute.So you think，wow，it must need a lot of energy，a lot of food，right？ Well，it does.It drinks a lot of nectar from flowers and feeds on some insects，but it’s energy-efficient，too.You can’t say it isn’t.I mean，as it flies all the way across the Gulf of Mexico，it uses up almost none of its body fat.But that doesn’t mean it doesn’t need to eat.So humming birds have to rely on plants in their natural habitat.
And it goes without saying，but，well，the opposite is true as well，plants depend on humming birds too.There are some flowers that can only be pollinated by the humming birds.Without its stopping to feed and spreading pollen from flower to flower，these plants would cease to exist.
But the problem，well，as natural habitat along these migration routes is developed by humans for housing or agriculture or cleared for raising cattle，for instance，there is less food available for migrating humming birds.Their nesting sites are affected too，the same，by the same sorts of human activities.And all of these activities pose a real threat to the humming bird population.
So to help them survive，we need to preserve their habitats.And one of the concrete ways people have been doing this is by cleaning up polluted habitat areas and then replanting flowers，um，replanting native flowers that humming birds feed on.
Questions：
1.What does the professor mainly discuss？
2.Which is the right description of the hummingbird？
3.What does the professor imply might cause a decrease in the hummingbird population？
4.What does the professor say people have done to help hummingbirds survive？
参考译文
我们一直在讨论在房产开发和，呃……城市发展中动物栖息地的减少——为数并不太多。今天我想谈论大片的栖息地在减少的时候都发生了什么。当然，动物需要大面积的栖息地，也有迁徙的物种越过很长的距离。那么，栖息地的缩减对需要大量栖息地的物种有什么影响呢？
我举一个蜂鸟的例子。
大家都知道蜂鸟体形超小，但尽管它很小，它迁徙时得飞到很远的地方，南北横跨西半球——美洲，在夏季的繁殖地和气候暖和一点的越冬地来回迁徙。这样你会说它们迁徙跨越的这片土地就是它们的栖息地，因为在它们长途迁移的过程中它们需要时不时停下来进食和休息，是吧？
蜂鸟扇动着翅膀——明白不——大约每分钟3千次。所以你会认为，哇，它们一定需要很多能量，很多食物，对吧？是的，确实这样。它们得喝很多花蜜，吃昆虫，其实它们也很节能的。这一点你得承认。我是说，当它们飞过墨西哥湾时，它们并没有耗尽身体的脂肪。但这并不意味着它们不需要进食。所以蜂鸟必须依赖自然栖息地的植物。
这是不言而喻的，但反过来也有道理，植物也依赖蜂鸟。一些花只靠蜂鸟来授粉。如果蜂鸟不停下来在花丛中觅食或传播花粉，这些植物就不复存在。
但问题是：随着人类对沿蜂鸟迁徙路线上的自然栖息地进行开发，如扩建住房，或是耕作，或是放牧，这样下来，迁徙途中的蜂鸟能找到的食物就变少了。它们的筑巢区也会受到影响，原因也是诸如此类的人类活动。同时，人类所有的这些活动对蜂鸟种群造成真正的威胁。
所以要帮助它们生存，人类需要保护它们的栖息地。人们一直以来采取的保护蜂鸟栖息地的具体措施之一是清理受到污染的栖息地，然后重栽花草，呃，重栽蜂鸟赖以生存的本土花草。
参考答案
1.C 2.D 3.B 4.C