新视野大学英语 读写教程第三册 unit6-b

　　Section (B)Changes in the Balance of NaturePerceptions are relative.

A single tree may seem large compared to a person. If you compare it to a mountain, however, thelarge tree seems small. In other words, things in nature are large or small, new or old, only inaccordance with the measures and the comparisons involved.

During the duration of one human lifetime, not many things change. Even trees live longer thanpeople, and the Earth itself is far older. The Earth was formed about five billion years ago from arotating, circular cloud of dust and gases such as hydrogen and nitrogen. A billion years later, the planethad cooled, and the continents and the great bodies of water had formed.

About 3.5 billion years ago, another great change occurred. The oceans began to develop anenormous system of living things, with many diverse forms of life, all dependent on one another. Thefirst animals on this living sphere, the Earth, were primitive 1 marine 2 animals, and then around 500million years ago these sea animals developed shells. Seventy million years later, the first fishappeared. Next, insects developed, about 400 million years ago. After another 200 million years,dinosaurs and the first mammals walked the Earth. About 200 million years ago, warm-bloodedanimals took to the air — the first birds. Fifty million years later, both birds and mammals were wellestablished. About three million years ago, scientists believe, the first human beings walked the Earth.

Life was now flourishing.

In terms of the evolution of life on Earth, human beings have just arrived. Despite their short time onEarth, however, people have brought about enormous changes to the surface of the planet — changesfar out of proportion to the interval 3 of time they have occupied it.

People Try to Control ResourcesPeople have more control over their surroundings than any other species on Earth. With thecombination of intelligence and manual skill (allowing us to make and use tools), people have foundways to use plant and animal resources, mineral ores, fuels, and many other of Earth's materials andresources.

As the number of people on Earth increases, it becomes increasingly difficult for the population tosurvive on the resources of the land. The amount of land is limited. Although agricultural productioncan be increased by use of machinery 4 such as tractors and the addition of fertilizer, the land ultimatelycan produce only so much food and no more. As the human population grows, people consume more.

Clearly, some locations on Earth already have too many people; in many of these areas, futureincreases will surely bring about more poverty and suffering. Yet people in rich nations useproportionally far more of the available resources than people in poorer nations. As they consume theseresources without restraint, they also waste large amounts of them.

People are only a very small fraction of all the living things on the planet. Yet their numbers create adrain on resources that can't be renewed. For example, the amount of water on Earth is limited; thiswater is cleaned through natural processes. However, the natural processes for filtering water can cleanonly a certain amount of water by removing the pollution.

Likewise, a limited amount of petroleum 5 can be found under the Earth's surface. Petroleum is avaluable resource. Should people use it up to manufacture petrol for automobiles 6? As people work tocontrol the planet and make life comfortable, are they using up resources that are needed for theirsurvival?

The Balance of NatureAll natural systems tend toward balance among opposing factors or forces. Human activities cancause or accelerate permanent changes in natural systems. The smoke of one small fire causes no harmto the environment. Natural cleaning processes can clean the particles of smoke from the air. However,the collective smoke from thousands of factories, over the past two centuries, has caused enormousincreases in air pollution levels worldwide. Cleaning this smoke has exceeded the protective ability ofnatural processes. The forests cannot clean the air fast enough.

In spite of rapid population increase and industrial growth, some groups of people, often in remoteareas, have been able to live in harmony with the planet. These people have not changed their ways ofliving from the ways of their ancestors. Called native peoples, they retain the ways of life that haveremained unchanged for many generations. Many of their cultural values and ways of life includepractices that return resources to the Earth.

Human population growth is creating food shortages, problems of air quality, and changes in weatherpatterns. What is destroying rain forests and ruining the land and seas? What causes the acid rain thatforms from water passing through polluted air? Why is there the threat of global warming? All theseharmful results come from the too much use of resources and the human struggle to control theenvironment.

The twentieth century began with powerful countries competing to take advantage of the Earth. Asan outcome of their hunger for empires, the Earth was abused. Now people all over the world are livingwith the problems caused by this abuse. Now that they are no longer ignorant of the causes of thesickness of our planet, they seek ways to help the Earth, to give back what they take away. Previously,mankind only used the Earth. Now everyone must protect planet Earth, a planet in danger.

　　New Words

perception n. 1.感知，感觉，知觉 2.认识，观点，看法

accordance n. 一致，和谐

duration n. 持续，持续期间

rotate v. 1.（使）旋转，（使）转动 2.（使）轮流

circular a. 圆形的，圆的

hydrogen n. 氢

nitrogen n. 氮

sphere n. 1.球形，球体 2.范围，领域

primitive a. 1.原始的，早期的 2.简陋的，粗糙的

shell n. 1.壳，贝壳 2.炮弹

vt. 剥... ...的壳

insect n. 昆虫，虫

■dinosaur n. 恐龙

■mammal n. 哺乳动物

flourish vi. 茂盛，繁荣，兴旺

vt. 挥舞

evolution n. 1.进化 2.演变，发展

manual a. 手工制作的，人工的

n. 操作手册，指南

ore n. 矿石，矿砂

tractor n. 拖拉机

fertilizer n. 肥料，化肥

location n. 1.地点，位置 2.（电影的）外景拍摄地

proportional a. 与... ...成比例的

proportionally ad. 与... ...成比例地

restraint n. 1.克制，抑制，约束 2.限制因素，约束措施

fraction n. 小部分，片段

renew vt. 1.更新，补充 2.注入新的生命和精力，使恢复 3.延长期效

petroleum n. 石油

manufacture vt. 1.（大量）制造，加工 2.编造

petrol n. 汽油

oppose vt. 反对，反抗

accelerate v. 加速，促进

particle n. 粒子，微粒

collective a. 集体的，共同的

n. 集体，团体

exceed vt. 超过，胜过，越出

protective a. 保护的，防护的

remote a. 1.遥远的，偏僻的 2.关系疏远的，脱离的，与……没有联系的 3.绝少的，微乎其微的

ancestor n. 1.祖先，祖宗，先人 2.雏形，原型

retain vt. 保留，保存

shortage n. 缺乏，不足

threat n. 1.构成威胁的人或事物 2.威胁，恐吓 3.凶兆，征兆

empire n. 1.帝国 2.（由一个人、一个家族或集团控制的）大企业

abuse vt. 1.滥用，妄用 2.虐待，凌辱

n. 1.滥用，妄用 2.虐待

ignorant a. 1.不知道的 2.愚昧的，无知的

mankind n. 人类

Phrases and Expressions

compared to/with 跟……相比

in other words 换句话说，也就是说

in accordance with 依照；与... ...一致

be formed from 由……构成, 由……做成

take to 开始 (从事) 喜欢上 逃入；躲藏于

in terms of 就……而论

bring about 使发生

out of proportion to sth. 与... ...极不成比例的，大大超过... ...的

survive on 靠……活下来，靠……生存

so much 这么多（表示未明确指出的数或量）

use up 用尽，用光

in harmony with 与……协调一致，与……相配

take advantage of 利用

hunger for sth. 得到某事物的渴望

live with 接受，容忍

be ignorant of 不知道，不了解

give back 归还

take away 拿走，带走