用户登录  |  用户注册 首 页下载论文听力动漫常用工具苏教人教新课标高中生自考在线教案作文

网站首页 | 试题中心 | 一轮复习 | 二轮专题 | 三轮冲刺 | 在线听力 | 教育论坛 | 家长学校
动画资源 | 自考资料 | 优秀作文 | 在线教案 | 状元纪实 | 园丁风采 | 学习方法 | 高考新闻

当前位置:免费教育资源网听力大学英语第四册→ 大学英语精读第四册>>-Unit Two:Deer and the Energy Cycle
大学英语精读第四册>>-Unit Two:Deer and the Energy Cycle
听力类型: - 大学英语 - 第四册
听力大小:0 Bytes


Is there anything we can learn from deer? During the "energy crisis" of 1973-1974 the writer of this essay was living in northern Minnesota and was able to observe how deer survive when winter arrives. The lessons he learns about he way deer conserve energy turn out applicable to our everyday life.

Some persons say that love makes the world go round. Others of a less romantic and more practical turn of mind say that it isn't love; it's money. But the truth is that it is energy that makes the world go round. Energy is the currency of the ecological system and life becomes possible only when food is converted into energy, which in turn is used to seek more food to grow, to reproduce and to survive. On this cycle all life depends.
It is fairly well known that wild animals survive from year to year by eating as much as they can during times of plenty, the summer and fall, storing the excess, usually in the form of fat, and then using these reserves of fat to survive during the hard times in winter when food is scarce. But it is probably less well known that even with their stored fat, wild animals spend less energy to live in winter than in summer.
A good case in point is the whiter-tailed deer. Like most wildlife, deer reproduce, grow, and store fat in the summer and fall when there is plenty of nutritious food available. A physically mature female deer in good condition who has conceived in November and given birth to two fawns during the end of May or first part of June, must search for food for the necessary energy not only to meet her body's needs but also to produce milk for her fawns. The best milk production occurs at the same time that new plant growth is available. This is good timing, because milk production is an energy consuming process — it requires a lot of food. The cost can not be met unless the region has ample food resources.
As the summer progresses and the fawns grow, they become less dependent on their mother's milk and more dependent on growing plants as food sources. The adult males spend the summer growing antlers and getting fat. Both males and females continue to eat high quality food in the fall in order to deposit body fat for the winter. In the case of does and fawns, a great deal of energy is expended either in milk production or in growing, and fat is not accumulated as quickly as it is in full grown males. Fat reserves are like bank accounts to be drawn on in the winter when food supplies are limited and sometimes difficult to reach because of deep snow.
As fall turns into winter, other changes take place. Fawns lose their spotted coat. Hair on all the deer becomes darker and thicker. The change in the hair coats is usually complete by September and maximum hair depths are reached by November or December when the weather becomes cold.
But in addition, nature provides a further safeguard to help deer survive the winter—an internal physiological response which lowers their metabolism, or rate of bodily functioning, and hence slows down their expenditure of energy. The deer become somewhat slow and drowsy. The heart rate drops. Animals that hibernate practice energy conservation to a greater extreme than deer do. Although deer don't hibernate, they do the same thing with their seasonal rhythms in metabolism. Deer spend more energy and store fat in the summer and fall when food is abundant, and spend less energy and use stored fat in the winter when food is less available.
When the "energy crisis" first came in 1973-1974, I was living with my family in a cabin on the edge of an area where deer spend the winter in northern Minnesota, observing the deer as their behavior changed from more activity in summer and fall to less as winter progressed, followed by an increase again in the spring as the snow melted. It was interesting and rather amusing to listen to the advice given on the radio: " Drive only when necessary," we were told. "Put on more clothes to stay warm, and turn the thermostat on your furnace down." Meanwhile we watched the deer reduce their activity, grow a winter coat of hair, and reduce their metabolism as they have for thousands of years. It is biologically reasonable for deer to reduce their cost of living to increase their chance of surviving in winter.
Not every winter is critical for deer of course. If the winter has light snow, survival and productivity next spring will be high. But if deep snows come and the weather remains cold for several weeks, then the deer must spend more energy to move about, food will be harder to find, and they must then depend more on their fat reserves to pull them through. If such conditions go on for too long some will die, and only the largest and strongest are likely to survive. That is a fundamental rule of life for wild, free wandering animal such as deer.
Yes, life—and death, too -- is a cycle that goes round and round, and when animals die their bodies become food for other life forms to use by converting them into energy.
And the cycle continues.

New Words
n. (sing. or pl.)鹿

a. belonging to or suggesting romance; fanciful not practical 浪漫的;幻想的

n. a natural tendency; inclination(天生)倾向

n. money that is actually in use in a country 通货,货币

a. of or concerning interrelationship of organisms and their environment 生态的

n. 生态学

vt. change (from one form, use, etc. into another); cause (a person) to change his beliefs, etc. 使转变;使改变信仰(等)

n. the part that is more than enough; the condition of exceeding what is usual or necessary 过量;过度

n. sth. that is being or has been stored for later use 储备(物)

scarce a. not available in sufficient quantity 缺乏的

n. animals and plants which live and grow wild

a. full grown and developed 成熟的;成年的

a. of the sex that gives birth to young 女(性)的;雌的
n. a female person, animal or plant

vt. become pregnant with (young); form (an idea, plan, etc.) in the mind 怀(胎);构思

n. a young deer less than a year old

n. selection for maximum effect of the precise moment for beginning or doing sth. 时机的选择

vt. eat or drink; use; use up 消耗;消费

n. a place, space or area; a part of the body 地区;(身体的)部位

a. plentiful 充裕的

n. (pl.) possessions (esp. of a country). in the form of wealth and goods, that help one to do what one wants 资源

a. relying (on another) for support

a. of the sex that does not give birth to young 男(性)的;雄的
n. a male person, animal or plant

n. the solid, bony horn of a male deer 鹿角,茸角

vt. put or store for safe keeping; (esp. of a liquid, a river) leave lying (a layer of matter)存放;使沉积

n. a fully-grown female deer

vt. spend or use up 花费;耗尽

v. make or become greater in number or quantity; collect or gather 积累;积聚

n. a sum of money kept in a bank which may be added to or taken from 帐户;存款

a. marked with spots

n. the state or degree of being deep 深;深度,厚度

n. a means of protection against sth. unwanted 预防措施

a. of or in the inside, esp. of the body 内部的;体内的

a. 生理的;生理学的

n. 新陈代谢

ad. therefore 因此,所以

n. expending or using up; the amount of money, time, etc. expended 花费;用光;支出额,费用

ad. by some degree or amount; a little 有点,稍微

a. sleepy or half sleepy; making one sleepy 困倦的;催眠的

vi. (of some animals) pass the whole of the winter in a state like sleep 冬眠

n. either end of anything; highest degree 极端

a. depending on the season; changing with the seasons 季节性的

n. 节奏

a. more than enough 充足的;丰富的

n. a small roughly built, usu. wooden house 小木屋;茅舍

v. cause (a solid) to become liquid; (of a solid ) become liquid (使)融化;(使)熔化

a. funny 逗人笑的;引起乐趣的

vt. cause to laugh or smile

n. an automatic device for regulating temperature 恒温器

ad. 生物学上

biological a.

n. the fact or likelihood of surviving 幸存

n. the ability or capacity to produce, productiveness 生产力;生产率;多产

a. basic; most important

Phrases & Expressions
go round
function smoothly

in the form of

in point
appropriate; pertinent 适用的;相关的

in (good) condition
in good health, physically fit

give birth (to)
bear; (fig.) produce 生(孩)子,产(仔);产生,引起

draw on
take or use as a source 利用;动用

slow down
(cause to ) go more slowly than usual; (cause to ) live, work, etc. in a less active and intense way (使)慢下来;(使)放松

turn down
reduce the force, speed, loudness, etc. of (sth.) by using controls 减弱;关小,调低

move about
travel around; go from one place to another

pull through
help (sb.) to survive a period of danger or crisis 使渡过危险或危机

Proper Name

点这里下载 →
点这里下载 →
点这里下载 →
点这里下载 →
点这里下载 →
点这里下载 →
点这里下载 →
点这里下载 →
点这里下载 →
点这里下载 →


* 为了达到最快的下载速度,推荐使用网际快车迅雷下载本站软件。
* 请一定升级到最新版WinRAR3.80才能正常解压本站提供的软件!
* 如果您发现下载链接错误,请点击报告错误谢谢!
* 站内提供的所有软件包含破解及注册码均是由网上搜集,若侵犯了你的版权利益,敬请来信通知我们!
  • 人教版小学数学一年级下学期全部
  • 必修一第二章 第3节 氧化还原反应
  • 第2章 化学物质及其变化第2节 离
  • 第2章 化学物质及其变化 学案 第
  • 第3节 物质的量浓度(第3课时)导
  • 第2节 化学计量在实验中的应用(
  • 第2节 化学计量在实验中的应用(
  • 第1章 从实验学化学 学案第一节
  • 第1节 化学实验基本方法(第2课时
  • 第一章 从实验学化学 第一节 化学
  • 高一化学必修1全套精品导学案133
  • 2009年山东省临沂市高三英语3月教
  • 北京十一学校高三英语月考试卷

  • 本类top12