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NARRATOR:Listen to part of a lecture in a biology class.
FEMALE PROFESSOR:Almost all animals have some way of regulating their body temperature; otherwise, they wouldn’t survive extreme hot or cold conditions.Sweating, panting, swimming to cooler or warmer water, ducking into somewhere cool like a burrow or a hole under a rock ... these are just a few.And that spot is colder or warmer than the surrounding environment because it's a microclimate.A microclimate is a group of climate conditions that affect a localized area, weather features like temperature, wind, moisture and so on.And when I say localized, I mean really localized, because microclimates can be, as the name suggests, pretty small, even less than a square meter.And microclimates are affected by a huge number of other variables … obviously weather conditions in the surrounding area are a factor.But other aspects of the location like... um... the elevation of the land, the plant life nearby and so on, have a substantial effect on microclimates.And, of course, the human development in the area... um... a road will affect a nearby microclimate.It's also interesting to note that microclimates that are near each other can have very different conditions.In the forest for example, there can be a number of very different microclimates close to each other because of all the variables I just mentioned.
MALE STUDENT:So how does a hole in the ground, a burrow, stay cool in a hot climate?
FEMALE PROFESSOR:Well, since cold air sinks, and these spots are shaded, they are usually much cooler than the surrounding area.And these spots are so important because many animals rely on microclimates to regulate their body temperature.Umm … for instance there is a species of squirrel in the western part of the United States that can get really hot when they are out foraging for food, so they need a way to cool down.So what do they do? They go back to their own burrow.Once they get there, their body temperatures decrease very very quickly.The trip to the burrow prevents the squirrel from getting too hot.
MALE STUDENT:But squirrels are mammals right? I thought mammals regulated their temperature internally …
FEMALE PROFESSOR:Mammals do have the ability to regulate their body temperature … but not all can do it to the same degree, or even the same way.Like when you walk outside on a hot day, you perspire and your body cools itself down, a classic example of how a mammal regulates its own body temperature.But one challenge that squirrels face, well, many small mammals do, is that because of their size, sweating would make them lose too much moisture; they dehydrate.But on the other hand, their small size allows them to fit into very tiny spaces.So for small mammals, microclimates can make a big difference—they rely on microclimates for survival.
MALE STUDENT:So cold-blooded animals, like reptiles—they can't control their own body temperature, so I can imagine the effect a microclimate would have on them.
FEMALE PROFESSOR:Yes. Many reptiles and insects rely on microclimates to control their body temperature.A lot of reptiles use burrows … or stay under rocks to cool down.Of course, with reptiles, it's a balancing act.Staying in the heat for too long can lead to problems, but staying in the cold can do the same.So reptiles have to be really precise about where they spend their time, even how they position their bodies.And when I say they are precise, I mean it—some snakes will search out a place under rocks of a specific thickness, because too thin a rock doesn’t keep them cool enough and too thick a rock will cause them to get too cold.That level of precision is critical to the snake for maintaining its body temperature.And even microscopic organisms rely on microclimates for survival.
Think about this: decomposing leaves create heat that warms the soil; the warm soil in turn affects the growth, the conditions of organisms there, and those organisms then affect the rate of decomposition of the leaves …So a microclimate can be something so small and so easily disturbed that even a tiny change can have a big impact.If someone on a hike knocks a couple of rocks over, they could be unwittingly destroying a microclimate that an animal or organism relies on.
旁白：请听一段生物学课上的演讲。
教授：几乎所有动物都有某种调节身体温度的方法；不然他们就不能在极其炎热或寒冷的条件下生存。流汗，喘气，或是游到更凉或更温的水域里；躲进凉爽的地方，像是冰冷的地洞或岩石下的洞穴......这些只是少数例子而已。在这些地方，他们的身体温度要比周遭的环境低或高，因为这就是小气候。所谓小气候，指的是一组气候条件，这些条件可能会影响到局部区域，那里的气候特征，包括气温，风，和湿度等等。而当我说到局部，我指的是小范围的，因为小气候就像其名字表明的一样，很小，甚至小于一平方米。而小气候会受到大量其他变量所影响，很明显周围区域的气候条件就是因素之一。而该区域的其他方面因素，像，地面的海拔，周围的植物等等，会对小气候区域起到极大的影响。当然，还有该区域的人类发展，呃，建一条公路也会影响到周边的小气候。同时有趣的是，相邻的两种小气候的环境条件可能会大相径庭。比如，森林里就有大量的相邻小气候区域，其环境截然不同，这就是因为我所提到的各种不同的可变因素。
学生：那么地下的洞穴，地洞，是怎么在炎热的气候中保持清凉的呢？
教授：嗯，由于冷空气沉降，并且这些地方被遮蔽着，所以温度经常比周边环境的要低。而这些地区是很重要的，因为很多动物就是依靠小气候来调节其身体温度的。比如说，有一种松鼠，栖息在美国西部地区，当他们外出觅食的时候，身体会变得很热，所以他们需要找到降温的方法。那么他们怎么做呢？他们会回到自己的地洞中。一旦他们回到地洞，他们身体温度就会急速下降。到达地洞的过程可以防止松鼠身体变得太热。
学生：但松鼠是哺乳动物不是吗？我认为哺乳动物会自身内部调节身体温度。
教授：哺乳动物确实有能力调节自己的体温，但不是所有都能达到同样的水平，或以同样的方式。就像在炎热的天气你在外面走，就会流汗，你的身体会自我冷却，这是一个哺乳动物是怎么调节自身体温的经典例子。但是松鼠面临的一个挑战，很多小型哺乳动物都会面临的，就是由于体型问题，一流汗就会流失太多水分。他们会脱水。但另一方面讲，正因为他们体型小，使它们能够在狭窄的空间中活动。所以对于小型的哺乳动物来讲，小气候意义重大，他们依靠小气候而得以生存。
学生：那么冷血动物呢，像爬行类动物，他们不能控制自己的体温，所以我能想象得出小气候对他们的影响。
教授：是的。很多爬行动物和昆虫都依靠小气候来控制自己的体温。很多爬行动物通过待在洞穴中或岩石底下来降低体温。当然对于爬行动物来说，这是一种平衡的行为。在热环境中待过长时间的话会出现问题，而在冷环境中也是。所以爬行类动物必须精确把握在某种环境中的时间，甚至是如何安置它们的身体。当我说精确的时候，我的意思是，某些蛇类会在某一块厚度适宜的石头下寻找落脚的地方，因为如果石头厚度不够，蛇便不能保持低体温，而太厚了会让他们体温太低。这种精确度对于保持体温的蛇来说是至关重要的。甚至是微生物也要依赖小气候生存。
想想看：叶子分解会产生热量使土壤变暖；温暖的土壤反过来影响那里有机物的生存条件，这些有机物又影响了叶子分解的速度。所以小气候是很小的，很容易受到干扰，一点点改变会造成大影响。如果有人在徒步旅行的时候撞到了某些石头，他们就可能无意间破坏了某一种动物或微生物赖以生存的小气候区域环境。
题型分类：主旨题
原文定位：
Almost all animals have some way of regulating their body temperature. Otherwise, they wouldn't survive extreme hot or cold conditions. Sweating, panting, swimming to cooler or warmer water, ducking into somewhere cool like a burrow or a hole under a rock...these are just a few. And that spot is colder or warmer than the surrounding environment because it's a microclimate.
选项分析：
主旨需要听完全后概括总结，全文都是关于 microclimates 和其对于生物的重要性的，所以选项D正确。
如果对题目有疑问，欢迎来提出你的问题，热心的小伙伴会帮你解答。