Tài liệu A Citizen''''s Guide to Ecology ppt

A Citizen's Guide to Ecology

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A Citizen's Guide to Ecology

Lawrence B. Slobodkin

OXFORD UNIVERSITY PRESS

20O3

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OXFORD

Oxford New York

Auckland Bangkok Buenos Aires Cape Town

Chennai Dares Salaam Delhi Hong Kong Istanbul

Karachi Kolkata Kuala Lumpur Madrid Melbourne

Mexico City Mumbai Nairobi Sao Paulo Shanghai

Taipei Tokyo Toronto

Copyright © 2003 by Lawrence B. Slobodkin

Published by Oxford University Press, Inc.

198 Madison Avenue, New York, New York 10016

www.oup.com

Oxford is a registered trademark of Oxford University Press

All rights reserved. No part of this publication may be reproduced,

stored in a retrieval system, or transmitted, in any form or by any means,

electronic, mechanical, photocopying, recording, or otherwise,

without the prior permission of Oxford University Press.

Library of Congress Cataloging-in-Publication Data

Slobodkin, Lawrence B.

A citizen's guide to ecology /

by Lawrence B. Slobodkin.

p. cm. Includes bibliographical references and index.

ISBN 0-19-516286-2 (cl.) —0-19-516287-0 (pbk.)

1. Ecology. 2. Nature—Effect of human beings on. I. Title.

QH541.S54 2003 577—dc21 2002072826

987654321

Printed in the United States of America

on recycled, acid-free paper

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To Yan, Mathew and Liaht

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Contents

Acknowledgments ix

Introduction 3

Defining Ecology 3

Changes 5

Why Another Ecology Book? 12

Who Are Ecologists? 22

1 THE BIG PICTURE 33

Water and Energy: Life's Necessities 33

The Origin of Life and of Atmospheric Oxygen 43

Big Systems 52.

Lakes 52

Lakes Through the Seasons 60

Oceans 73

Dry Land 81

How Independent Are Ecological Systems? 95

2 HOW DO SPECIES SURVIVE? 101

Populations 101

Individuals and Populations 115

Species Diversity 127

Species Extinction 139

Are All Invasive Species Villains? 144

3 TWO MAJOR CURRENT PROBLEMS 155

Global Warming and Endangered Species 155

What Can Be Done About Global Warming? 156

Protecting Endangered Species 166

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APPLYING ECOLOGY 177

Experts, Pseudoexperts, and How to Tell Them Apart 177

The Importance of Being Natural and Vegetarian 189

Medicine and Ecology as "Health" Sciences 195

Conclusions 205

Appendix 213

References 215

Index 231

4

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Acknowledgments

My wife, Tamara, and daughter, Naomi, put up with me during

endless writing and rewriting.

My colleague Manuel Lerdau provided important criticism. I

also tried out other ideas on Stony Brook colleagues, particu￾larly Dan Dykhuizen, Mike Bell, Charles Janson, Lev Ginzburg,

Jessica Gurevitch, and Geeta Bharathan.

Doug Futuyama, Yossi Loya, Rob Colwell, Uzi Ritte, Rosina

Bierbaum, Phil Dustan, Scott Person, and Conrad Istock are

among my former doctoral students who taught me more than

I taught them.

Since 1947, my friend Fred Smith of Woods Hole has pro￾vided wisdom.

The late Evelyn Hutchinson of Yale demonstrated to me that

ecology is worth a life's effort.

Kirk Jensen has provided important, patient criticism and

encouragement well beyond the usual role of an editor.

I have omitted the names of many other people who have

been important in my life. A list of who they are and what I

learned from each of them would be a thicker book than this

one. I ask their indulgence.

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A Citizen's Guide to Ecology

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Introduction

DEFINING ECOLOGY

Ecology studies interactions among organisms and between or￾ganisms and their environment in nature and is also concerned

with the effects that organisms have on the inanimate environ￾ment. It is concerned with not only what kind of air a species

must have but also what effect that species has on the air.

This book is not an elementary ecology textbook. A textbook

would be longer and more didactic. Ideally it would present a

survey of what is being done by the 7,600 members of the

American Ecological Society and their students and collabora￾tors, and it would prepare students for more advanced, special￾ized books covering one or more of the sixteen subdivisions of

the science of ecology that are listed by the society.

This book is simply a description of what happens outdoors

today. What has been happening outdoors for the past billion or

so years? Has it changed much and is it likely to change further?

How do you and I fit into the changes and the constancies?

I have two goals. One is to enhance appreciation of the pleas￾ure and beauty to be found in nature. Another goal is to help in￾dividual citizens understand the real and unreal assertions about

existing problems and impending disasters in nature.

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4 A CITIZEN'S GUIDE TO ECOLOGY

There is one important difference between ecology and

many other fascinating sciences and games: Unsolved problems

of chess, astronomy, or mathematics will not change if we

ignore them.1

Our activity or lack of activity can alter the state

of ecology. A major focus of ecology is on determining how

certain aspects of the natural world change or do not change.

We must ask:

• What properties of our environment will stay constant, re￾gardless of what we do?

• What changes are inevitable?

• Are particular changes desirable?

In the first chapter of this book I will present some of the

large-scale mechanisms that underlie all of ecological change

and constancy. Chapter 2 focuses on individual organisms,

species, and landscapes. The third chapter examines how we can

reach reasonable conclusions about specific practical problems.

Chapter I describes big, inexorable processes that are almost

Wagnerian. The second chapter describes smaller, quicker, more

complicated, and sometimes almost playful processes that are

more like Mozart. Chapter 3 struggles to make sense out of

how the material in the first two chapters is used in making

decisions.

Motives for the study of ecology range from a sense of awe

to a sense of alarm. The study of nature can be a purely intel￾lectual exercise or can focus on practical problems. Fortunately,

the world in which ecological problems appear is extremely

beautiful, and thinking about ecology can be a great pleasure.

Descriptions of nature can be dramatic. The list of characters

includes molecules, mountain ranges, lions, butterflies, real ser￾pents and dragons, and ultimately all of humanity.

There is a temptation to infer mysterious causes for natural

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