原文已被隐藏，你可用 快捷键 - 或点击 显示原文 按钮来查看原文
第一段
1 .Listen to part of a lecture in a biology class.
该句暂无译文！
第二段
1 .Okay,so that's how the arctic ground squirrel's able to cope in this extreme environment.
该句暂无译文！
2 .Now let's talk about your reading assignment,about reindeer,also typically found in Siberia and other far northern regions.
该句暂无译文！
3 .Who would like to start off?Yes,Mike?
该句暂无译文！
第三段
1 .Well,for one thing,they've got thick hair all over their body,even on their noses.
该句暂无译文！
第四段
1 .Yes.They are very well insulated,and the thickness of their fur varies depending on the season.
该句暂无译文！
2 .Good.Yes?
该句暂无译文！
第五段
1 .Um...newborn reindeer are very adult-like,like they can stand as soon as they're born,
该句暂无译文！
2 .and by their second day they can already run as fast as a human.
该句暂无译文！
第六段
1 .Critical.Food is very scarce in far north so reindeer herds have to cover lots of ground every day.
该句暂无译文！
2 .And in the fall they might easily trek a thousand kilometers or more to get to their winter feeding site.
该句暂无译文！
3 .So if you are a newborn you've got to get up to speed fast.
该句暂无译文！
第七段
1 .Okay Other adaptations?
该句暂无译文！
第八段
1 .Also reindeer don't have to keep their legs as warm as their main body,so they don't have to use up as much energy keeping them warm.
该句暂无译文！
第九段
1 .Yes,so that means they can allocate less energy to heating their extremities and more energy to maintaining stable temperature in their body core where their vital organs are located.
该句暂无译文！
2 .And you know I don't think it is mentioned in your textbook,
该句暂无译文！
3 .but even different parts of a reindeers leg are adapted for optimal cold weather performance.
该句暂无译文！
4 .The fat in the lower part of their legs,the part that gets coldest,that fat has a different chemical structure from the fat in the upper parts of the leg.
该句暂无译文！
5 .So it doesn't get hard,even at temperatures down around freezing,it stays kind of gel-like,kind of oily.
该句暂无译文！
第十段
1 .Okay, good.What about food?
该句暂无译文！
2 .What do you remember about that?
该句暂无译文！
第十一段
1 .Well,they are pretty flexible.
该句暂无译文！
第十二段
1 .OK,can you explain that a little more?
该句暂无译文！
第十三段
1 .Well,they can eat a lot of different kinds of plants,so that improves their chances of coming across something they can eat.
该句暂无译文！
2 .I think they said that they found that the reindeer in one herd had something like 37 different kinds of plants.
该句暂无译文！
第十四段
1 .OK,yes.You've really done your reading.
该句暂无译文！
2 .And reindeer also eat a number of different plant species that most animals are not very interested in.
该句暂无译文！
3 .Which means?
该句暂无译文！
第十五段
1 .They don't have a lot of competition when it comes to that food?
该句暂无译文！
第十六段
1 .That's right.
该句暂无译文！
2 .In particular,your reading mentions lichens.
该句暂无译文！
3 .Lichens are plants you'll find growing on rocks in the far north,sometimes referred to as reindeer moss.
该句暂无译文！
4 .They look pretty basic you know,just a little moss on a rock.
该句暂无译文！
第十七段
1 .But lichens are actually quite complex.
该句暂无译文！
2 .They are not just a single organism.
该句暂无译文！
3 .They're actually kind of combination of some sort of fungus and some sort of algae that lire together in a symbiotic relationship.
该句暂无译文！
第十八段
1 .Anyway...Okay,reindeer,um,oh,oh yes,and one more thing about lichens.
该句暂无译文！
2 .They crank out a lot of chemicals,which is probably at least part of the reason why they are not considered all that tasty by most animals.
该句暂无译文！
3 .Anyway,does anyone remember what your reading said about them?
该句暂无译文！
第一十九段
1 .Yeah,somehow when reindeer eat lichens they're able to draw a lot more nutrients from them than other animals.
该句暂无译文！
2 .Like if a cow or a sheep eats lichens,they're only gonna get like half as much nutrition out af them as a reindeer would.
该句暂无译文！
第二十段
1 .That's right,and in winter,lichens are crucial for reindeer because their supply energy,
该句暂无译文！
2 .but they don't have all the proteins and minerals the reindeer need.
该句暂无译文！
第二十一段
1 .Um,so when reindeer get to the end of the long winter they are often very thin with low levels of minerals.
该句暂无译文！
第二十二段
1 .In spring they have to eat different plants and replenish what they've lost over the winter,
该句暂无译文！
2 .so what reindeer have done is they've developed the ability to digest different plants in different seasons by adjusting the microbes in their digestive systems.
该句暂无译文！
3 .As you know microbes are micro-organisms like bacteria that help to digest or break down food.
该句暂无译文！