Psychology. Copy right © 1976 by Harper & Row, Publishers, Incorporated.

Printed in t he United States of America. All right s reserved. No part of t his boo kmay be used or reproduced in any manner what soever without written permissionexcept in the case of brief quotations em bodied in critica l art icles and reviews.For information address Harper & Row, Publishers, Inc., 10 East 53rd St reet ,New York, N.Y. 10022.

Int ern at ional Standard Book Number: 0·06·168401·5Library of Congress Cata log Card Number : 75-25946

Edited by Elizabeth L.C. Wolf, Caroline Eastman, Raleigh Wilson, Barbara E. Swart

DG§iaAGa BV §GA 1(9AAComposit ion by Susan WiltseColo r work by Kevan MillerMechan ically prepared by Sharon SattlerProdu ced by Behaviordelia and Ben KannPrinted by Kingsport Press

A POINT OF VIEW

ABOUT THE CONTENT OFPSYCHOLOGY

We've had a great deal of fun in writing and producing this book, asyou can tell by just glancing at it. But we've also put our most seriousintellectual efforts into it, though you may need to go beneath itssurface before that becomes apparent. It's our heaviest work, in spiteof our attempt at a light style. And in trying to deal with much ofthe field of current psychology, we've regressed to nineteeth centuryfu nctionalism. That is, we look at what others may treat as mentalphenomena, instead treating them as processes or actions. We askwhat functions these processes serve in helping the species surviveand in rewarding the actions of the individual.

We start with a biological and evolutionary view of psychologywhich plays a role throughout the book. Then we look at the learning,

... "....... ........

sensory, and perceptual processes. We've also found a functionalframework useful in looking at much of the cognitive work in develop­mental psychology by Jean Piaget, as well as much of the cognitivework in social psychology. That same functionalist view allows us tolook at a good deal of the work of Sigmund Freud as processesresulting from the inherited structure of the individual, and as rewardsand punishers from the individual's past and present environment.

So we've covered much of the standard field of psychology, thoughnot from an eclectic point of view - one that often results in a set ofunrelated topics. Rather, we've taken a unified approach showinghow many of the topics of psychology relate to each other; and, atthe same time, showing how this unified view, the functionalist view,can unite some of these approaches - evolutionary, biological,behavioral, cognitive, social, and dynamic.

We stress the knowledge the science of psychology has given us, tryingto show how this knowledge aIlows us to understand ou r own everydayworld, and trying to show how we can use it to help ourselves andothers lead better lives. You may also wish to use the book, Introduc­tion to the Science ofPsychology, to study the methods used to findthat knowledge. That book was written to go along with t-his one,and presents the science of psychology in a useful, clear, and pleasantmanner.

VI PREFACE

WRITTEN WITHSTUDENTS IN MIND

SEXISM AND RACISM

In many ways, we've tried to create a text designed for you students .First we present psychology so you can relate to it. We present mostof the topics in terms of even ts selected to be of interest to you.Throughout, the book weaves a story about the lives of six studentsat Big State University, involved in the intro psych course, whoportray concepts covered in this book through events in their lives.They reflect features of people we all know, including ourselves . Insome cases , they seem a little extreme - much better, or much worse,than real life - in fact, we often picked extremes to make our points;but those extremes do exist. Look around you.

Besides showing some basic concepts, and some of our humanfeatures, we hope the story also makes the book more rewarding toread . We've written in an informal and personal style, hoping tomake your studying easy and pleasant. We've made an effort not tofill the book with unused technical terms, while at the same timewe've brought in key concepts, dealing with them as needed . We'vewanted to avoid making the concepts of psychology appear simplerthan they really are, as many of the concepts are indeed quitecomplex; instead, we've attempted to present these complex conceptsin an informal and personal manner. In the same manner, Ed Badajoscreated the art to achieve these three goals , and to illustrate the basicconcepts in a 'helpful way.

You can read more of what we have to say about writing style inthe first part of the Notes section at the back of the book, where

ycnilU also find tile bibliography and occasional comments we\iemade about each chapter.

Though written and designed for students, we hope teachers, ourcolleagues, will also find this book of value, since we thought thethings we put in the book are of value to us as professional psychol­ogists as well as to you students.

We've hoped to give you some tools that may be of use to you inyour efforts to help yourself and our society move toward a morejust position. We've tried to do this by looking at some of the reasonsfor why things are as they are, rather than merely presenting thingsas we fed they should be . For instance, we mention the problem thatnot all women, or men, or Blacks, or Whites are indeed free fromharmful cultural constraints in how they treat themselves and others.And those people who seem to be, may have mixed motives, comingas we all do from our traditional culture. The people in our story areoften involved in these problems, sometimes as the present source ofthe problem, sometimes as the victim, sometimes as both the sou teeand the victim, and sometimes as the solver.

We've also made an effort to write in a non-sexist, non-rascist style,by avoiding male words as generic pronouns (e.g., the reader ... , he ...),while showing people in roles other than the standard way they'restereotyped for their sex or race.

BASED ON INSTRUCTIONALTECHNOLOGY

PREFACE VII

Instructional technology is the art and science of using what weknow from psychology and other areas to develop improved ways ofhelping people learn. This book is a product of such instructionaltechnology.

We've already mentioned some of the features of this technology.For instance, we've made the book as rewarding as we were ableso you'll more likely read it, since you need to read it before you canlearn from it.

We've tried to be fairly practical as we planned this book, puttingaside many of our prejudices about what a book should be like, howmuch knowledge and how many facts it should contain, and howmuch you should learn from it. Instead we've gotten a rough idea ofhow much students really can learn from a single course , and usedthat as a guide to determine how much material we presented.

It seems best to present many of the key concepts of psychology,spending a good deal of time trying to get a feel for those concepts .We've avoided making a superficial sweep at all of the hundreds ofconcepts of psychology, knowing full well you'd only be able to

master a small portion of those ; and besides people forget most ofthose superficially presented concepts shortly after the final examanyway. So rather than leave that whole process to chance, weselected some of the most crucial concepts, presenting them in a waywe hope will help you make use of many of them long after thiscourse is over. We hope this book and this course will have a great

effect on your life ana tRe way you ]001<at your life.We've also profited by the large amount of useful feedback from

many students as well as teachers who were good enough to readparts of our work. The student feedback was of great value in helpingus decide how to present psychology so you ' iii understand, value, andenjoy it.

We've also seen that you can learn best, if you don't have to playthe guessing game : What am I supposed to learn? Learning worksmuch better when everyone's up front about the course or text goals ­what they expect you to learn. So we've given you a road map ofsorts : all of the major concepts in each chapter are set off in boldface followed by a definition of that concept - a fact you'll find ofimmense value as you review for quizzes and exams. The conceptsare also defined in the Glossary at the end of this book.

And we 've placed study objectives at the end of each section,pointing to the crucial concepts. They're of great value in helpingyou find au t whether you've gotten the key points from each chapter.These study objectives are the numbered questions at the end of eachof the sections. You should answer them as you read the text , rereadingany sections where you're not sure you've made the correct answer.You may also wish to use the workbook , Introduction to the ConceptsofPsychology, to be even more certain of mastering the material orconcepts of the present text. That book goes along with this one, asit's designed to help you master the study objectives for this text.

We hope that you' ll enjoy this text, that you'll learn from it, andthat you'll find something of use in it.

ACKNOWLEDGMENTS We would like to thank thefollowing academic reviewers fortheir very generous and helpfulcomments, though, of course ,the point of view and any short­comings the book may containare our responsibility;

Galen Alessi , Western MichiganUniversity ; Gordon Anderson,Jamestown Community College ;Peter]. Behrens, PennsylvaniaState University (Allentown) ;Joseph A. Besso, Jr., North TexasState University; Kathy Buckheit ,Southeast Community College;Roy E. Cain, Pan American Uni­versity; Thomas D'Andrea, Haver­ford College; Erhard Eimer,Wittenberg University; HowardFarris, Western Michigan Univer­sity; Nancy Faulk, Western Mich­igan University; Barb Fult on ,Western Michigan University;William H. Glaze, North Texas

State University; ftalpR WHansen,Augustana College; Curt Hulteen,Blackhawk Community College ;Marilyn Gilbert Komechak, NorthTexas State University; JamesKopp , University of Texas (Ar­lington); Thomas Lawson, WesternMichigan University; John Lelak ,Sinclair Community College;Kass Lockhart, Western MichiganUniversity; James R. Lott, NorthTexas State University; KayMalott, Western Michigan Univer­sity; Richard P. McGlynn, TexasTechnological University; JackMichael, Western Michig an Uni­versity; George R . Mount, Moun­tainview College; Steve Mozara,Galveston Junior College; JamesA . Newell, Galveston JuniorCollege; Ron Olson, Western

Michigan University; Dan G.Perkins , Richland CommunityCollege; LeRoy P. Richardson,Montgomery County CommunityCollege; Arthur Snapper, WesternMichigan University; TravisThompson, University of Minne­sota; Richard V. Wagner, BatesCollege; Robert ]. Weber, Okla­homa State University; MaryPeterson Sojourner Weiss, Uni­versity of Rochester; Scott Wood,Drake University.

To make this a student-orientedtext, we've also found it veryhelpful to get feedback from stu­dents and others. In addition tothe students involved in classroomvalidation, we would like to thankthe following people for theirknowledgeable suggestions:

Sharian Deering, Janet Ellis, RoyElrod, Franklin Fordham,

J MicRael Gautney, Dale General,Sigrid Glenn, Lyle Grant, DonnaHicks, Harvey Jacobs , BeverlyLouisell, Susan Rucker, WalterScott, Vivian Snapper, Greg Stike­leather, Tim Trainor, SuanneWilliams.

The following cleric al andresearch staff gave us truly excel­lent help beyond the reasonablecall of duty:

June Asselin , Sharian Deering,Jan Delger, Sue 0 'Connor, SusanRucker, Mary Anne Slomski,Marilyn Walker, Elizabeth Whaley.

We'd also like to thank ourproofreaders, Frank Gallowayand Mary Ann Bowman.

INTRODUCTIONThe book's main characters strugglethrough college registration, raisingsome basic issues for the science ofpsychology along the way.

BIOPHYSICAL STRUCTUREWe evolved from simple to complexstructures: from atoms, to molecules ,to cells, to multi-celled creatures, andat last to complex creatures. Each levelreaches its most complex stage beforecombining to form subunits of the. .. _ . .

next higher level.

PHYSIOLOGICAL PROCESSESOur actions are produ cts of our ana­tomy and physiology, the structureand function of our bodies.

EVOLUTION AND BEHAVIORNature's forces select biological struc­tures, causing us to act in usefu l ways,allowing us to evolve with actions well­suited to our world (at least to thewor ld where we evolved).

MOTIVATION OF LEARNEDACTSOur learning is based on events thathelped our ancestors survive - eventslike getting fuel and escaping harm.

MOTIVATION INDIRECTLYRELATED TO BIOLOGICALNEEDWe may best understand imprinting,instinct, and aggression, when we seethat a creature's actions can be con­trolled by strange rewards if thoseactions themselves helped their speciessurvive.

LEARNING : BASIC ELEMENTSOur actions tend to be more controlledby the results that come right afterthem than by distant results.

LEARNING : FACTORSAFFECTING LEARNINGMany factors control our actions otherthan the mere receipt of rewards ­factors such as the removal and patternof delivery of rewards, and the stimulipresent when we get them.

LEARNING : LEARNEDRESULTS AND GENERAL­IZATIONLearned rewards, learned punishers,and learned concepts are crucial forhuman actions, though they are basedon processes found in simpler creatures.

SENSORY PROCESSESWe've become better able to survive inour world as we've evolved sensorycapacities allowing us to respond tomore and more of the details of thatworld. Now the products of socialevolut ion may be taking over fromnatural evolution.

PERCEPTIONWe may be able to dispe l some of t hemystery surrounding the field of per­ception if we look at it as control bycomplex stimuli, with the standard lawsof behavior and natural selection stillapplying.

1111111&IIIII

DEVELOPMENT OFBASIC RESPONSESIn what way do heredity and environ ­ment affect how our children develop?We can greatly help our children, if weknow the answers.

DEVELOPMENT OFLANGUAGEWe can improve the way our childrenlearn to speak and understand langu­age through the careful use of re­wards.

DEVELOPMENTOF INTELLIGENCE9Hfe~l!sr!n m~y~! mHe~ ~!n!f gffif we help them learn components ofintelligent behavior such as orientingand language skills.

JEAN PIAGET AND THEDEVELOPMENT OFCOGNITIVE BEHAVIORWeget the notion that our learned cog­nitive acts can control our externalactions, when we combine Piaget'scognitive approach with a behavioralapproach.

SOCIAL REINFORCEMENTSocial rewards, such as attention andapproval, affect us all, causing us to bethe kinds of people we are - rationalor silly, pleasant or grouchy, steady orflighty. Social rewards may evendetermine whether or not we go tocollege.

SOCIAL VALUESSocial factors cause us to have certainlearned rewards and punishers. In turn,those learned values affect much ofwhat we do and who we like.

ATTITUDE CHANGEWomen's liberation provides manygood examples of the factors affectingour attitudes about crucial issues.

MORALITYUnlike lower animals, we civilizedcreatures need moral control to survive.But moral control is a fragile process,sometimes causing problems. Variouslevels of moral control affect how werespond to the chance to cheat incollege.

SOCIAL ROLESWe tend to play the same social rolesin the same setting, though we mayswitch roles when the setting changes.This depends on what roles are reowarded - whether we're rewarded forbeing the scientist or the theologian,the model child or the college radical.

SIGMUND FREUDAND PERSONALITYWe can still learn much from Freud'sclassic theory with its stress on sexualand aggressive rewards, social-moralcontrol, and rational control.

CONSCIOUSNESS:MEANINGS AND DEFINITIONSWe learn self·awareness from the peoplewho affect how we use our language.

CONSCIOUSNESS ASPRIVATE ACTIVITYWe learn from and are rewarded byour fantasies, by what we say to our­selves in private. Those fantasies cancontrol what we do later in reality.

CONSCIOUSNESS ANDITS LIMITSPain, hypnosis, and meditation are allrelated to self-awareness, and muchconfusion is eliminated in the process.

EMOTIONSEmotions are our physiological reac­tions to crucial events in our world.Often emotions prepare us to dealwith those events though sometimesthe y may harm us. Such reactions mayalso function as unlearned and learnedrewards and punishers.

PIli ILIIIIILPIIILIIiI

HANS SELYE AND STRESSIn coping with stress, we may findways that give us longer, more healthy,less stressful , lives, but it's alwaysrisky business.

NEUROSESInept patterns of handling stress takemany forms called neuroses. Theseneuroses often fail to fade away, per­sisting t hroughout a person's life,sometimes leading to psychoses andconfinement.

OVERVIEW XI

BEHAVIOR PROBLEMSProblem behaviors occur because ofthe strong control of immediate reowards. Better actions may not occur,though they payoff more in the longrun, because, at best, distant rewardsexert weak control.

PSYCHOSESOften an environment may do muchto produce and maintain psychoticactions, though it seems warm andloving. It's always worthwhile to insurethat normal actions are the ones thatget the rewards, even with psychosesthat may have organic roots.

RETARDATIONNew and powerful training techniquesprovide the greatest help for the re­tarded as they help overcome some ofthe problems caused by brain damagearid genetic and congeriiiai factors.

TIIIIPIII

B. F. SKINNER ANDBEHAVIOR MODIFICATIONBehavior mod, a useful new approach,deals with human problems, rangingfrom the training of the retarded, tothe bizarre actions of the psychotic, tothe little, everyday trials we allconfront.

JOSEPH WOLPE ANDBEHAVIOR THERAPYThis new therapy helps get rid of manyproblems, such as those involving sex,test anxiety, and lack of assertiveness.

PREFACE

ACKNOWLEDGEMENTS

INTRODUCTION, 2Of M ice and Syst ems, 2Psychology, 4Inhe ritance, Learning, and Evolut ion, 10System Insensit ivity and Ind iv idua I Needs, 14T he Sexes, 14

TEIIIT

BIOPHYSICAL STRUCTURES, 2 1Complexity and lnstabilltv of Structure, 2 1Single Cell Reproduction , 26The Life Explos ion, 28Or igi n of Mul t i-Cell ed Creatures, 30Complex ity and Mutat ion in Mult i-Cell ed Creatures, 34Conclusion s - The Great Mutation, 41

PHYSIOLOGICAL PROCESSES, 42Introduction, 42Structu re and Funct ion , 42Simple St imulus Transfer, Absorption, and Transformation , 43Major Stimulus Tran sfer Systems, 46The Function of the Nervous System, 48Structure of the Nervous System, 52Conclusions, 5 7

I

XIV CONTENTS

Ii

7

EVOLUTION AND BEHAVIOR, 58Introduction, 58Passive Life, 59Active Life, 61Evolution, 62Purposivism, 66Basic Causes of Action, 68Habituation, 72Basic St imulus Control, 74Feedback Stimulus Control, 77Conclusions, 81

MOTIVATION OF LEARNED ACTS, 82Introduction, 82Operant Conditioning, 83Reinforcers, 90Respondent Conditioning, 96Operant vs. Respondent Conditioning, 100Conclusions, 101

MOTIVATION INDIRECTLY RELATED TO BIOLOGICAL NEED, 102Introduction, 102Imprinting, 103Laboratory Research, 106Instinct - Instinctive Reinforcers, 108Purposivism Revisited, 113Aggression, 114Defining Mot ivat ion, 124Emotions, 126

ConclUsions, 121

LEARNING: BASIC ELEMENTS, 128When Creatures First Learned , 128The Law of Immediate Results, 130Awareness and Learning, 134The Law of Repeated Delayed Results , 136Delayed Results and Mediation, 138The Bait-Shy Effect, 140Conclusions, 141

LEARNING: FACTORS AFFECTING LEARNING, 142Shaping : The Method of Successive Approximation, 142Extinction, 146Extinction and Other Factors, 150St imulus Control, 154Intermittent Reinforcement, 160Conclusions, 163Postscript, 163

LEARNING: LEARNED RESULTS AND GENERALIZATION, 164Learned Results, 164How Learned Reinforcers are Established, 166Learned Punishers, 171How Learned Results Lose Their Power, 172Unlearned or Simple Stimulus Generalization, 174Learned Stimulus Generalization : Concept Formation, 178Response Generalization, 184Conclusions, 189

I

II

12

I

III

I

SENSORY PROCESSES, 190The Sensory Response, 190Vision, 192Hearing, 198Tissue Damage, 200Evolution, 202Conclusions, 203

PERCEPTION, 204Introduction, 204The View Over the Cliff, 206Analysis of the View, 208Other Perceptua I Effects, 215Sensory and Perceptual Stimulus Control, 220Conclusions, 222

I IlLDEVELOPMENT OF BASIC RESPONSES, 225Introduction, 225Phylogenetic and Ontogenetic Development, 226Prenatal Development, 228Maturation vs. Learning, 230Ingestion, 232Irritants - Harmful States, 235Sensory -Motor Responses, 238The Developmental Sequence, 241.......... I • •• '.. ... •

The Natural and the Helping Approaches, 245Conclusions, 249

DEVELOPMENT OF LANGUAGE, 250Introduction, 250 .Understanding Speech, 251Before Language, 254Learning Complex Speech, 258The Functions of Language, 268Conclusions, 279

DEVELOPMENT OF INTELLIGENCE, 280Introduction, 280Basic Skills, 281Prerequisites, 290Psychological Tests, 291What is Intelligence, 294Conclusions, 295

JEAN PIAGET AND THE DEVELOPMENTOF COGNITIVE BEHAVIOR, 296Introduction, 296Sensory -Motor Period, 297Preoperational Period, 302Concrete-Operational Period, 308Formal-Operational Period, 315The Cognitive-Behavioral Approach, 316Conclusions, 317

CONTENTS XV

XVI CONTENTS

17

I

I

II

SOCIAL REINFORCEMENT, 318Introduction, 318Types of Social Reinforcement, 319Concerns About Social Reinforcement, 324Rat ional ity and Soc ial Reinforcement, 326Conclusions, 329

SOCIAL VALUES, 330Introduction, 330Im itation , 331Interpersonal Attraction and the Cultural Program, 334Establishing Values, 336Other Causes of Interpersonal Attraction, 340Gregar iousness and the Group, 342A ssociation and Interpersonal Attraction , 344Conclusions, 345

ATTITUDE CHANGE, 346Attitude and Its Components, 346Attitude Change, 350Inconsistent Attitudes and Rat ional ization , 358Conclusions, 359

MORALITY, 360Forms of Control, 360Pre-Moral Control, 364Guilt - A Form of Internal , Pre-Moral Control , 368Rule-Governed Moral Control, 371

~lniemjl Mer91 GenUel; n~Conclusion s, 375

SOCIAL ROLES, 376Roles, 37 6Peer Control, 380Conformity, 384Conclusions, 38 7

SIGMUND FREUD AND PERSONALITY, 388Introduction , 388Control Processes, 390Psychic Needs and Mental Health, 394Displacement, 396The Role of Sex, 404Personality, 404Conclusions, 409

CONSCIOUSNESS: MEANINGS AND DEFINITIONS, 410Introduction, 410Consciousness as Activation, 410Consciousness as Stimulus Control, 412Self-Awareness, 414Repression, 416Learning Consciousness, 4 20Conclusions, 423

CONSCIOUSNESS AS PRIVATE ACTIVITY, 424Introduction , 424Private Consciou sness, 426Words are Cues, 43 0Conclusions, 437

CONTENTS XVII

CONSCIOUSNESS AND ITS LIMITS, 438Introduction , 438Pain, 44 0Hypnosis, 446Meditation, 450Conclusions, 455

EMOTIONS, 456Introd uction , 456What is Emotion?, 459Sti mul i Th at Cause Emotion, 460The Many Sources of Emotion , 461Words: Cues and Learned Warn ing Signals, 462Feelings and Emot ion, 468Kinds of Emot ion , 470Emotions as Reinforcers, 4 72Conclusions, 474

HANS SELYE AND STRESS, 4 77Stimu li,4 77Learned and Unl earned Stressors, 4 79General Ad aptation Syndrome, 482Psychophys iologic Disorders, 488Types of Psychophysiolog ic Di sorder, 490Hanging in With Stress, 492Conc lusions , 495

NEUROSES, 496Introduction, 496The MMPI and N eurot ics, 498Self-Defeating Behavio r, 502Kind s of Neuroses, 504Anx iety Neurosi s, 512Conclusions, 517

BEHAVIOR PROBLEMS, 518Introduction , 518Production Defect or Behavior Prob lem?, 519Masochism, 520Self -Abuse and Social Reinforcement, 524Learn ing Maladaptive Behavior, 526Delayed Gratificat ion, 530Conclusions, 531

XVIII CONTENTS

PSYCHOSES, 532Neuroses , Behavior Problems, and Psychoses, 532Biological Psychoses , 536Psychogen ic Psychoses, 537Response Bias , 544Social Reinfo rcement and Psychotic Acts , 548Psychic Needs and Mental Health , 550Love and Humanism, 552One Cause of a Psychotic Response, 554Conclusions , 55 7Postscript, 557

RETARDATION, 558Introduction, 558Psychoses, Retardat ion, and Cultural Deprivation, 559Causes of Retardation , 561Ste reotyping and Brain Damage, 564Stereotyping and Stimu lus Control , 5 72Teaching the Retarded, 574Conclusions, 5 74

B. F. SKINNER AND BEHAVIOR MODIFICATION, 577

Introduction, 577Extinction Procedu res and B Mod , 582- . .. .. . ...... . . - _ ....

Task Analysis and Selection, 586B Mod and Self-Control, 592

The Pay off , 59 5Conclus ions, 595

JOSEPH WOLPE AND BEHAVIOR THERAPY, 596

Introduction - At the Zoo, 596Learned Pun ishers in Sexual Behavior, 598

Systematic Desensitization , 602

Assertive Training, 606

Technique, 60 8Co nclusions, 61 1

NOTES, 6 12

GLOSSARY, 67 1

INDEX, 68 1

IIIPTIIIIIIITIIIIITIIIII

OF MICE AND SYSTEMS

"Present your yellow top card .Present your yellow top card .Present your yellow top card .Present your yellow top card "A y ellow sign flashed the messageas the transcribed voice dronedon. "Present y our yellow top

tan!:"Sid looked at the yellow

top card he had clutched for thefifty or so minutes he had beenwaiting in line : FIELDS SIDNEYW 2 201 NR DUM The lettersand numbers meant some thing,of course , but what? The "2 " heguessed meant that he was asophomore. The NR? Hm mm ­could m ean non-resident. Toobad, if he was a resident, hewouldn 't have to pay such highfees . The "201 "? He had heardthat it stood fo r your major. InSid's case, "201 " would have tomean Psy chology.

Sid closed his eyes . Soundswere all around ; voices - faceless

torment of registration .

4 INTRODUCTION

PSYCHOLOGY

Definition

Yes, Sid Fields, one of the characters that we'll stay with through thepages of this book, is a psychology major. He plans to earn a degreein that subject - as perhaps many who are reading this book intendto do. Less than a century ago neither Sid, nor you for that matter,could have majored in psychology. At that time psychology was nota separate field of study. It was part of philosophy. People whostudied psychology were still called philosophers.

But what is psychology in our day and age? What do psychologistsdo? Like most people , Sid isn't quite sure . Sure, he's heard thatpsychology is "the study of the mind" - whatever that means . Thetruth is that it doesn't mean much at all. Today, most psychologistswouldn't go along with such a dated description of what they'resupposed to be doing. Their big complaint would likely involve theterm, "mind". As it turns out, it's a vague term that so many peopletake to mean such different things that in net result, it means little ornothing.

What do psychologists study then if they don't study the mind?As you will see, they study behavior, and a wide range of eventsdealing with behavior in both humans, and other creatures. We'lltalk about most of these events. Some in more detail than others.

Psychology: the study of behavior.

• 1 Within what discipline did psychology first begin?• 2 Why do most modern psychologists object to defining

psychology as lithe study of the mind"?• 3 What is psychology?

CHAPTEH 1 INTRODUCTION 5

Order

"Hey, move up!" Sid's eyes snapped open. There was a gap in the linein front of him.

"Sorry." There were only two in front of him now. Sid could seethe girl who was taking the ID pictures. Why was she taking so long?Sid thought to himself. Why did it all have to be such a pain? Ifenough planning and time went in to it, it could be worked out - nostanding in line, no hassles - smooth as silk . But then, didn't heexpect too much'? Sid thought of Uncle Jason , his father's oldestbrother. Uncle Jason had studied to be a rabbi ; then stricken by poliowhen he was eighteen, he gave up his studies - but not his wisdom .Sid smiled . He could almost see Uncle Jason now ; his head twistedto the side, chin cocked outward like a bulldog - scars of the illness.

"Order - psht! What do we know about order? A fable, a story wetell ourselves. If things run well, if they go smooth, it is a mistake, afreak. Mark my words, there's too much to the cosmos, too much torun, too much to ever know. What farce to presume to run theworld! "

At last it was Sid's turn -r- he was next. But what was wrong? Thegirl was fooling around with the machine, a grim and harried look onher face. It seemed to Sid that her tinkering was endless . Would he

§pfm{j th~ r~§t (3f hi§ lif~ hn~ in th~ mtm '§ Dm = ,[rew eM ami {jig;here at registration?

The girl walked over to Sid. She looked very upset. "Look," shesaid, "something's wrong with the machine ..It happens - it just getsmessed up." Sid gulped in spite of himself.

"What do I do now?" he asked." I' ll just mark your card , so you can go on," the girl said . "Keep

looking for a notice in the Daily. It should let you know aboutgetting an ID picture made later - okay?"

"Okay," Sid said. He tried to look friendly and unbothered."I'm sorry," she said. "God , what a hassle!""Yeah," Sid said . She left him to go break the bad news to the

long line of students.Sid had seen enough carnage for one day - he moved quickly

away, following the arrows to station seven. Maybe Uncle Jason wasright - maybe the idea that there was order was a lie - a lie we telleach other that lets us go on putting up with this topsy-turvy,rag-tag mess, without rhyme or reason , that doesn 't give a gooddiddle about any of us! Sidney laughed and looked around him atthe chaos. Better not ask us poor schnooks about it just now.

Gt:\\:J

ffl>."

The nature of it all

When one group of events always yields the same outcome, we saythey cause it to happen. "Cause" is the key word here. Once all theconditions are there , the outcome is bound to occur. This used to becalled "cause and effect", but nowadays we speak of it as "determinism".When the correct conditions are there, the outcome is determined.

Determinism: the notion that an event is produced or results fromthe active presence of a precise set of conditions.

Science: the systematic study of how events or occu rrences arerelated to the production of other events or occurrences.

Is it as Sid's Unele suggests - are all outcomes merely by chance?Perhaps. But for now it appears otherwise - some events lead in aquite regular fashion to others. Dark clouds precede rain; a seedplanted in the soil brings forth a plant. The study of how some eventsseem to produce others is called "science".

6 INTRODUCTION

~~

~~

The science of psychology is like other sciences in terms of thelogic it's based on. What people do is just as much "caused" as anyother event in nature. Thus, like other sciences, psychology has twomain parts: analysis; where the tie-ins among events - causes and ef­fects - are found; and application, where these facts are used tocontrol outcomes, making desired results occur.

Analysis: the task of finding out and describing the precise set ofconditions that give rise to specific events.

Application: the bringing together of the needed conditions in orderto produce certain desired events or outcomes.

• 4 What is meant by the notion that what happens to us is merelyby chance?

• 5 How did science originate?• 6 Define science.• 7 Briefly outline what is meant by "cause and effect".• 8 What is the modern term that has replaced cause and effect?• 9 How is the science of psychology like all other sciences?,~1 0 What are the two main parts or efforts in the science of

psychology?.11 Describe the first branch or part of the science of psychology.·12 Describe the second branch of the science of psychology.-13 Can you think of an example of how analysis and applied

psychology interact?

CHAPTER 1 INTRODUCTION 7

The haves and have nots

As Sid moved toward his destin yat station seven, he passed by agroup of five husky students inthe midst of a heavy rap .

"You 're fulla it, Red!" Liggitsaid . All the men wore Tshirtsmarked "Propert y of BSU", andthe emblem of Big State Univer­sity Coach Purvis ' plan was tohave the football squad sign upfor classes at the same time.

"g~9~r ~~!!~~~~": h~ ~~I!~~ !~:The team would eat, sleep, studyas a unit - take the same courseswhen they could.

"I ain 't gonna take nochemistry course , not thisnigger! "

"Come on man ," Red coaxed."It'll be a blast. We get ta mix upthem chemicals and stuff likethat. We can make us a bomb!"

"Yeah," Ragsdale said , "youdo that Red . You do that andblow your honky head off."

"You know, I sure would liketa make one a them patents, "Curly said. "You drink a glassa that an ' it turns you inta one athem mean muthas."

"Whada' you mean , Curly;you already Dr. Goof-off!"

Someone came from thecrowd to join the group. He wasdressed like the others. Standingat the edge of the huddle of

~~~!¥ ~~h!~~~~l h~ ~~~ ~!n9~Bthem , but apart. His name wasJuke.

"J ohn Henry Jackson!" Liggitsaid, as he caught a glimpse ofJuke. All heads snapped towardhim . "Welcome to the goin's on,my man!"

"Hey," Red said after thingshad died down. " Let 's ask Juke."

"Yeah, Juke," Liggit said ."This guy here wants us tosign up for chern ."

"What about it , Juke?» Okie

asked."Chemistry - no man ." Juke

shook his head. "No way!""Why'n the hell not!" Red

said."Cause they'll flunk you out

sure as my butt's black - that'swhy!"

"Come on, Juke . Hell, somaybe we'll have to study a little."

"Study? What's wrong with

~~!~ ~~~? !"!~¥l !n~~ : ~h~~ ¥9~been putting in your Gatoraide?"Ragsdale said.

"Study won't get it, Red . Yougotta be a brain to pass thatcourse. You can work your tailoff, get a tutor, st art going taSunday School, and that stillwon't cut it. I'm talkin ' aboutknowin ' what's gain' on - dig?Smart is something you gottahave in front - gotta be bornthat way. There' s things somepeople never can learn! "

***

Individual differences: the ideathat people differ in very basicways along various characteristics.

that there are individual differ­ences between them and otherswho will "pass the course withlittle trouble. These individualdifferences Juke suggests arecrucial.

After awhile, Juke left theteam, working his way alonethrough the morass of warmbodies to the class card tables.He took a trial class slip from hispocket and checked the list ofcourses . There it was; big as life:Chern 100. The same course he'dhassled about a few minutes ago.Seeing it on his list gave Juke atwinge of guilt. He'd been roughon old Red, but he was tryin' totell it straight. Red, Rags, Okie,

Individual differences

Juke's turned on to a fact aboutpeople that has kept psychologybusy right from the starr: We'reall different from each other. Ourlooks or features, what we likeand dislike, the size and shape ofour bodies - simply aren't thesame.

Another basic differenceinvolves skills. In our culture theworth of people is measured in

~~~!n~ ~f Y(~~~ ~~~r ~~~ ~~ ­skills they can perform, problemsthey can solve. Skill in jumping,running, and making your bodywor k, make a good athlete.Other skills - and the degree to

which they can be performed ­are basic to making a passingmark in chemistry or othercollege courses - even psych.

Juke's telling his friends andbrothers to stay out of coursesthat call for skills they're notlikely to have. He's telling them

10 INTRODUCTION

Liggit, they'd all flunk. So whywas he different? Well, he justwas. 'His dad never got out ofhigh school - his mother onlywent to the fifth grade. It didn'tmatter.

Juke looked again at the listof courses. Some pretty heavystuff there - could he make it?No, it wouldn't be like highschool. Hell. Man, I just gottafind out what this here niggercan do!

Just then he became awarethat he was staring at a girl whowalked toward him from theother end of the aisle. She was talland slight. She stopped for aninstant before going into thewomen's room and glanced up ­just long enough to see Jukestaring at her. Turning without aflicker, she went through thedoor.

-14 The fact that people are notalike in many respects hasprovided the" basis for atopic of study in psvcholoqvWhat is it?

-15 What is probably more im­portant in terms of howpeopJe are different thanphysical characteristics - atleast as far as the study ofpsychology is concerned?

INHERITANCE, LEARNING, AND EVOLUTION

Another topic closely tied toskills, and their lack or amplesupply, has to do with how theperson got them. Some things ­color of eyes, body features, etc.- we acquire when we're born.They are inherited - passed onat conception. But what aboutmemory? Recalling phonenumbers, words, ways to dothings? Some believe these skillsare likewise passed on fromparents. Juke's idea is "youeither got it or you don't". Inthis sense Juke is a "nativist",meaning he also seems to believethat if "you don't have it, youcan't get it." What's the answer?Is Juke right - or wrong? Inlater pages, we will try to findout what skills can be acquiredand separate them from those

that only the "right" parents cangive us.

Nativist: a person who tends tobelieve that people are born withbasic skills thatcannot beacquired through learning orexperience.

But sometimes there's a basicchange from parent to offspring.A child may be able to do thingshis parents never could. Whenlife forms change in a gradualway across time and generationsin their skill to get along orsurvive, it is called evolution. Theterm is most often applied tobiology, where it refers to changesin a species structure that occurfrom parent to offspring. But

this is far too narrow a way tolook at it. We will also discussother kinds of evolution in thisbook.

Evolution: a change, that occursacross generations, in the abil ityof a type of-creature to .deal withits environment.

-16 What is another area inpsychology that's closelytied to skills and how theydiffer from person toperson?

-17 What are the two waysmentioned in this chapterthat a person acquires skills?

-18 What is a nativist?-19 Define evolution.

The real things in life

Mae Robinson was at last safebeh ind the door of the women 's

.room . " Damn him! He had noright to look at me that way. Ifhe th inks I'm ju st another blackwom an wait ing like a melon tobe plucked from the vine,well ... " Mae stopped short."But th at's what I am - anotherblack woman. Wasn't that thepoint? Wasn't that why I came toBSU in the first place? "

Last year, Mae had gone toChristian College , a small privateliberal arts college , across town .The y tre ated her well there - afull ride, tuition , room - th eypaid it all . Pretty and bright, Maewas catered to , wined and dined .She could see wh at they thought.It was in their faces . " See - seehow liberal we are! We love black

pe6ple , tssl"It was fine for a time . At mid­

term she'd had second and thirdthoughts . She loved English ­her major - but wanted an act ivehand in shaping the future, inhelping to solve the problem s thatblack people - her people - hadto face. By the end of the springterm she had decided to leaveChristian , to go to BSU in the fall.Th ere were many blacks there ­she could learn their problemsand try to help. She wouldchange her major to psych .

Mae looked at herself in th emirror. "Well, Miss Hotshot Do­Good . Now wha t?" Mae saidaloud to herself. She lookedaround to see if she had beenoverheard . Voices came from th e

CHAPTE;R 1 INTRODUCTION 11

lounge are a." So I said to her, 'Well, Mom ,

wh at do you think the "real"thing is in college? ' and she said ,real huffy and bent outa shape ,'Obviously, Catherine , it 's to getsomething in your head besidespot and sex ; like for instance ,we 'd like you to learn enoughto get a job someday! At least ,Catherine, that's wh at your fatherand I think we're sacrificingfor!' "

"Hell ," another voice said ."It really burned me . I got

ticked at her. 'Look ', I said ,'n o matter wh at y ou think aboutit, mother, there 's more to lifethan just sayin g back a bunch ofdumb facts so you can get somedippy job ! Like - I'd like tofind myself;you know - wisdom ,

~R6Wle8ge , leaFR §Sffiet:BiRgabout people and relationships ­because frankly, Mother, I don 'twant to grow up to be the sameuptight bitch you are!' "

Mae winced . Had she reallysaid that to her mother? Butthere was more to it than coarsetalk. It was the way the girl feltabout school. It was a new ideafor Mae , and there was a lot of ithere. This morning in line shehad heard two students talking.

"But what 's so great about Lit200? You jus t said you don'tlearn anything ," on e of themsaid .

"A 'C' man! No stu dy, notests , and it 's in the bag to beginwith. "

12 INTRODUCTION

Mae couldn't help it. She got mad at these people. "School" ­she even liked the way the word sounded. Books, teachers - thesewere sacred to her; the y always had been . It wasn't true for others ­that much was clear. Yes , there was a lot to learn about here at BSU.Not all about black s, and not all would be pleasant.

She left the women's room. There was only one more courseshe needed. Classes started Monday. The transfer had been hectic.Oh, to have the weekend off! She would go to a movie or two, readsome good fiction , maybe sew on the dress she was making. That wasout. Reading lists were handed out with class cards in four of herclasses. There was work due Monday. Some of the profs here suredidn't waste time . Her weekend would be spent in the library. Maefelt a little sad. A new cam pus, new places to see and explore, andI'm going to be stuck in the library Do I aluiays have to do what I'msupposed to ?

Function and feeling

Most of us break the world down into what goes on in it - whathappens around us and to us - and how we feel about it. Someask : Which is more crucial - what we do or how we feel? Maeis surprised at some of her fellow students because they seem to

thin~ that fttlJng ~88EL Bting ha~~y; finging fhtill§t!¥t§; i§ thsonl y goal . Things the y are told to do - stud y, plan, work , tote thatbriefcase, lift th at book - are seen as a drag and a bore. Mae could beright in putting them down at that. But on the other hand, even Mae,tough as she is, still feels the strain of her chores. She often longs tobe free of the yoke. Well, what should she, they, we , do? We've got todo what it take s to make things go - but can we risk shutting outfeelings?

-20 Briefly summarize the conflict many people have in terms offunctioning and feelings.

CHAPTER 1 INTRODUCTION 13

Human vs. the system

If Mae had seen the clenched fists and red face of the man she passedat the English table, she would know that not all BSU students takeschool lightly.

"But I don't think you understand ... ))"On the contrary, Mr. uh, Mr... ))"LaPorte. ),"Yes, Mr. LaPorte, it's not I who fails to understand, I dare say, but

you. One cannot take 102 unless one has first gained an acceptablemark in 101. It is what is known as a 'prerequisite' You do knowwhat the word means, I trust, Mr. uh ..."

Chet felt his ears burn, students were looking at him. He took adeep breath, and set his feet.

"Look, it's this way. I got a wife and family and a job at theCentral Street Standard Station. I'd like to keep my wife and family,so I gotta keep my job. The only course I can take is 102."

"This may come as a surprise to you, but I, too, have a wife andI sympathize to the utmost with your struggle for an education, Godknows. But none of these data alter the fact that 101 must becompleted before one can be enrolled in 102."

"But I just ... ""I don't want to think you're a dullard, but you must grasp the

simple truth that if one were allowed to take 102 before having 101,he or she would undoubtedly flunk it with all possible alacrity!"

Chet turned his face downward and glared at his shoetops. Hefought back the choking sounds that wanted to eek from his throat.He couldn't think of anything else to say Picky little gnats, littlepeople pulling him down. Was everyone out to get him? WouldMickey Mouse never die?

-"Would you please tell me where I can find the DepartmentChairman?" Chet asked solemnly.

"Surely you're not -going to bother him with this?""I want to see the Chairman."The man behind the desk looked at Chet for perhaps the first time.

The tenseness, the grim set of his jaw - an older student - thesewere things he hadn't noticed. He became afraid of Chet. It showedin the way his eyes began to dart around as though looking for help."Ifyou must 'absolutely have it your way, I'll oblige you." He reachedfor the proper card. "However, 1 think it only fair to say that I'm notdoing you a favor, as you'll all too soon discover."

Chet grabbed the card and turned to walk to a nearby standingtable where he would fill it out.

"I'm not doing any favors for the instructor, either," the professoryelled, his courage bolstered as Chet walked away.

14 INTRODUCTION

SYSTEM INSENSITIVITY AND INDIVIDUAL NEEDS

THE SEXES

Chet looked at his watch, almostthree . Carol said she would meethim at the snack bar. She was onher afternoon break from theMental Health Clinic where sheworked as a receptionist.

When inside the snack bar,Chet spotted Carol at once. Shewas smiling; her hand in the airwaving to him. "Hi babe," Chetsaid. He kissed Carol quickly onthe cheek.

"How'd it go?" Carol asked."Did you get all the courses youwanted? "

Is nature on our side? Does itcare about us humans? Sorry,but "no" to both questions .We've come to accept the factthat nature is not on ours - oranyone's - side. Nature is. That'sall. We're on our own. If we werefoolish enough to leave it up tonature we could end up in a badway. Clearly, our job is to im­prove on the odds that naturegives. This often involves gettingaround our own (human) natures.When people try to build a wayof doing something better thanit would be done by nature orchance, it's called a system.

System: the placing of tasks,personnel, and machines into aunit to achieve a somewhatcomplex end result or function.

"Yeah," Chet said. "But ittook some doin '. This jerk fromEnglish wasn't going to let meinto 102. I talked him into it ,though. "

"But aren't you supposed to

take 101 first?""That's what that little twerp

gave me such a hard time about.""But 102's hard, Chet! You'll

never pass; you know how badyou were at camp in high school!"

"I'm not gain' to flunk! Whatthe hell do you know about it?"

"Cher, I've had the course .

As you might suspect, a univer­sity is a system for educating andtraining people. It does muchmore than that, and is thus reallymany systems within a system.

Both Chet and Sid havefigured out that there's a lot ofslop in the BSU system. This istrue to some extent of allsystems . How people relate tothe system is a topic we willcourt throughout this book.

-21 Whose side is nature on?-22 What have humans built to

improve on nature?-23 Define system.-24 There were two aspects of

the relationship betweenthe individual and the sys­tem that we will discuss inthis book. What were they?

I wasn't always a typist . I wasalmost a senior when I quit toget married, remember?"

"Here we go again . You wereon your way to being a big hot­shot scholar but I spoiled all ofthat, right? So maybe I'll takeyour job and you go to school!"

Here comes Dawn!

Dawn Baker started to feel better.The whole thing had been ashock - not the lines and themass of people. She liked crowds- she liked watching them,wondering about them. Wherewere they coming from? Wherewere they going? Would they befun to know? Would she impressthem? Could she get them tolike her? No, it wasn't the crowdsthat bothered her. It wasn't thesystem either. That was simple .AU you had to do was read anddo what it said; easy as pie. Itwas her hurt feelings. So manypeople didn't even seem to knowshe was there; didn't treat herspecial. It made her feel strange;empty inside - like she was lost.Maybe that's the way it was

WRen You~re cleacl. Dawnshuddered.

She looked around her at thecrowd in the student union .They were relaxed, not runningscared, hassled, harried. Therewas time, now.

At Central High she'd beenhead cheerleader, a big cheese inthe student council, prom

Female-male, male-female roles

There are many things to lookinto when the roles of the sexesin the culture are the topic ­history, for instance. How did theroles get to be the way they havebeen up to now? What part doesand did biology play? To whatextent are roles merely learnedor products of culture? Andlastly, what about the fu ture?

CHAPTER 1 INTRODUCTION 15

queen, homecoming queen - ahotshot. But what now? Littlefish in a big pond? A lot ofpretty faces and nice bod s in thebig U? Sure , she'd heard that.So what? It was time to makeher play. The group around thesoda fountain had thinned out.There was room for them to seeher. Now. The camera in herhead started to roll. She couldsee herself get up slowly; not toofast, easy, relaxed, poised - that'sit . Now, smooth the skirt - good!Perfect! Shoulders back, not toofar. Careful; walk loose like shewas strolling down by a countrystream. That's it. It was working.Little fish in a big pond , huh?Maybe not. The boy at thefountain came to take her order.

She wettea fief lips ana openeaher eyes wider.

"A small coke please - verylittle ice - if you can manageit." She smiled - a slight trickwith her lips. She could see herwords lilting from her lovelymouth, hanging like silver puffsin the air.

How will being equal work?What about the struggle itself ­will it cost more than it gains?

-25 What are some importantissues regarding female­male, male-female roles thatwill be discussed in thisbook? (Name three.)

16 INTRODUCTION

It's a new year

The football hung in the air for a month . Come on, Christmas!Juke said to himself. A in 't y ou never gonna' get here?

When it came, it fell lightly, like an angel cake in his arms. Jukehugged the ball. His cleats caught right in the turf, the muscles of hislegs strained , plunging him forward, shooting him past the red jerseys,grasping hands betrayed by the motion of their bodies. Seconds later,Juke was in the end zone.

"Ohwee!" Juke said . "This is gain' ta be some kind of a year!"

***

CHAPTER 1 INTRODUCTION 17

Mae came back to the dorm at 8: 3O. She pushed the elevatorbutton and waited. A few yards from her three fellows, two of themin tweedy coats, a third wearing a BSU letter sweater, talked to agirl. Mae looked away at first , but her eyes returned to gather inmore detail on the girl. She was striking. In fact, she was gorgeous.She could have 'been the co-ed in a TV ad - she was perfect - if youliked that kind of thing. Mae didn't .

"If you really mean that , you could go have a few beers and apizza with us," one of the men said .

"Beer! I couldn't do that. After all those cokes I'd wet my pantsfor sure." They all laughed.

Just then the elevator came. Mae got on fast . The scene with thegirl turned her off. High school stuff, she thought.

***Mae took a shower and changed into jeans. She was making a list

of what she had to do in the library when she heard a key turn in thedoor.

"Hi there," a tousled head of blond hair poked through thedoorway. "I'm Dawn - Dawn Baker. I guess I'm your roommate." Itwas the girl Mae'd just seen in the lobby. She was struggling with akey that was caught in the lock , trying to balance an armload of newbooks, a frown on her face. She turned and beamed at Mae, the. .frown gone in a split second. "Could you give me a hand here?"

Mae took the books without reply, and put them on the table.Dawn looked at Mae, puzzled by her silence. "I am in the right

room - 526?""Yes - I guess so. I'm Mae Robinson.""Good to meet you, Mae. Are you a freshman, too?""Soph - transfer student.""Oh ," Dawn said. "And you 're black. I mean - of course you're

black; anyone can . .. I mean, I always wanted a black roommate."Dawn was happy with what she'd said . She waited like a puppy thatthought it was about to get petted.

"Yes," Mae said. There was an awkward pause as Dawn waited forher to say more.

"Well - I guess I better go; these dudes're waiting downstairs . It'sgonn a be a great year, Mae." Dawn took Mae's hand and shook it."I know we're going to be the best of friends."

***

For some unknown reason Sidhad been given a roo m in the wingof the dorm th at housed the BSUathletes. All those jocks and Sid.Well, maybe it'd be ok ay. Hisroomm ate seemed like a goodman - a footb aller the y called"Juke". Seemed kinda quiet ,really . Sid liked him. Oh well ,time to take a loo k at the newbooks he'd just paid a fortunefor.

The pages crackled as Sidopened one of them . Holding thebook at arm's length , he read thetitle softly aloud : "Psychology.Well, Psy ch, we'll just see what Iknow after I've read you th at Idon 't kno w now! "

COMPLEXITY AND INSTABIUTY OF STRUCTURE

When atoms collide

" . .. on and on it goes - th esame process ; atoms collide,

ntUH8m fU§t ; ana Ehtrt tffitrgt§from this strife, a grander, moreeloquent str ucture. A morecomplex atom, a new wealth ofelectrons whirling about itscenter. Atomic evolu tion? Bio­ogy? Life? Call it that or call

it falling in love - for in someway it all seems the same." Dr.Burt paused , the bell sounded ,the period was over.

Sid Fields burst loose from thespell that had held him fast forthe past fifty minutes . Possessedwith courage foreign to him, heleaped to his feet and started toapplaud. Others joined in atonce. Soon the lecture hall wasfilled with the sound of twohundred intro physics studentspaying tr ibute. Professor Burtsmiled , bowed slightly, and leftthe podium. Sid started up theramp toward the exit , st ill

looking back at Dr. Burt who'dnot left the stage. Then some-

thing§WPPta hi§ pWgft§§ =something soft and yielding.

"'Scuse me," Sid said . Hejumped back, like he'd donesomething dreadful. The womanhe'd just knocked into wasturned toward him but her eyeswent past him, down front to­

ward Professor Burt. Sid saw acardboard badge pinned on hersweater. It said : "Back theBulldogs ! BSU BOOSTERS. Myname is Dawn Baker." She didn'tseem to notice th at Sid hadslammed into her; made no signto show that she'd heard hisapology.

"Isn't Dr. Burt just marvel­ous!" she said, looking at Sidfor the first time .

"She's a brilliant woman, " Sidmumbled .

"That was a fine thing youdid ," she said. "You were the

first , you know. They allfollowed you."

"Tht fifHF" §ia a§~tg:

"Yes - I was sitting behindyou. You were the first to standand applaud."

"Oh - yeah . .. uh . .. thanks."Was it true? May be it was. Goodtbing be hadn 't kn own it at th etime .

"I t was a great lecture . Shehad a way of making it all fit ­you know what I mean?"

"Uh . . . yeah, I think so.Relevant."

"Yes! Relevant , that's it.""Well . . . look ," Dawn said .

"I've got to get back to the dorm- I live at Co-ed. You aren'tgoing that way are you?"

"I live there too," Sid said ."Come to think of it there is abook I forgot to get ," he lied ."Might as well go get it now."

"Perfect !" Dawn said . "Nowwhat was it you were saying?"

22 BIOPHYSICAL BASES

When people first started toobserve the heavens, the world,life and matter all around, theywanted to know what was goingon. What was nature up to? Whatwas it trying to do? Not that itwas a person or anything likethat - but where was it going?Some looked and saw onlymotion. Matter was restless, everchanging. Order - or whatappeared to be order - was onlya phase in this eternal flux.Others also saw change, butbelieved it went in a certaindirection. All things movedtoward peace, stability, a state ofrest .

If you choose to supporteither of the notions above ,you'll have no trouble findingfacts, and others who see thingsthat way, to support you. But inthis chapter, we're going to try to

- . - ... .get you to consider still anotheraspect of nature - that all

around us, even at this instant,some parts of nature are movingtoward ever greater complexity.

Even now our sun, a "young"star, is in the first simple stage ofwhat may be called "atomicevolution ".

Atomic evolution: a processoccurring in nature where,through fusion of nuclei, simpleatoms evolve into more complexones.

The sun is called a young starbecause it 's almost purehydrogen . Hydrogen is thesimplest element, having onlyone electron whirling around itsnucleus . When nuclei of twohydrogen atoms collide, theirneutrons fuse under intense heat,releasing energy that comes to usas sunshine. What remains is a. .more complex atom - no longerhydrogen, but helium . There are

now two electrons that surrounda slightly altered nucleus . As theprocess goes on, nuclei of thesehelium atoms will collide,creating more complex atomsstill - beryllium, carbon,oxygen. So it goes, right ondown the line , each new atommore complex than the atomsfrom which it fused . Is there nolimit - can we expect the sunwill one day become a ball ofpure uranium, the most complexatoms found in nature ­uranium with ninety-two busyelectrons whirling about a heavycomplex nucleus?

• 1 What do we imply aboutthe composition of our sunby calling it a "young" star?

• 2 What atomic process isgoing on with our sun?

• 3 Define atomic evolution.

Atomic complexity and instability

CHAPTER 2 BIOPHY SICA L STRUCTURE 23

But what's so great abouturanium? Why does it end there?Is there something magic aboutthe atomic number ninety-two?In order to answer these ques­tions, a new concept - instability- is needed . As atoms becomecomplex they reac h a pointwhere they become unstable .The nucle i of these ato msbecome so loaded with pro tonsand other sub-ato mic parts tha tth ey can't remain intact - th eystart to break apart. Too mu chcomplexity . When atoms split orbre ak apar t , it's called "atomicfission ".

Physicis ts have shown howgreater complex ity leads to split­ting by producing elements in

The soup of creation

"Curnme re , J ackson , I got some ­thin' to show yo u! "

Ju ke saw th at it was th atLaPo rte guy - Chet LaPorte .Musta found something new togripe about. Tho ugh he'd o nlybeen at it a sho rt while , Ju keliked the job with the P.E.department . He was assigned tohelp Coac h Kru b conduct thefres hman Physical Condi tioningclasses . As it turned out , Co achKrub left it all up to J uke . Jukefound it wasn 't a bad deal. Forth e most part, the guys wereokay, but a few of them - liketh is LaPorte .. .

" Dammit, snap it up !" Chetsaid . "Thiss somethin ' you andthe rest of th is screwed up P.E.

the atomic lab that are mo recomplex than urani um. Theseato ms are so un st able th at theylast fo r only a fraction of asecond - th en break apart .

These two co ncep ts , complex­ity and instability, may help usmake more sense out of nature.We've seen how they apply at theato mic level. Since th ey alsoapply elsewhere , th ey can bethought of as two basic prin­ciples of str uc ture .

Principle of Complexity: asmatter ex ists and su rvives at anylevel (atoms, molecul es, ce lls,creatures, cultures, etc.) changesoccu r that te nd to ma ke someunits at that level more complex.

bunch sho uld see ." J uk e felt aru sh of anger.

When th ey reached theshowers, Chet sto pped andpointed inside. "Look at th at!"he ordered. Juke peered inside.Two huge centipedes wriggled onthe d imly lighted floor. Therewere three or fo ur small slugs, ahalf dozen other lon g-leggedspid er-looking things. "All themoney I gotta pay to take th isjerk course I didn 't want to takein the first place - and then Igotta t ake a shower in the middleof some damn chamb er a' creepyhorrors!"

J uke scowled , ru bbed his no se ." You 're r ight , man ," he said.

"What?" Chet said - it was

Principle of Instability: as asystem reac hes a ce rtain po int inco mplex ity, it becomes unstab lewh ich tends t o limit furthercomplexity - at least at t he levelof that system .

• 4 If scientists have createdmore complex elementsthan uranium where arethey now?

• 5 What are the two conceptsthat have been called basicprinciples of structure?

• 6 State the Pr inciple of Com ­plexity.

• 7 State t he Princ iple of Insta­bil ity.

like he hadn 't heard ." I don 't blame you - I

wouldn't go in there either.Look , go down the hall andshow er up in th e staff room . It 'sokay. I 'll see th e man 'bout th is.Somethin' gotta be done ."

"Well, I just thought I'd letyo u . . . Down th e hall?"

"Yeah, t o the right. ""J ackson , yo u're okay."Juke stood for some time

looking at the creature s in th edamp , war m, concrete shower.Don't want 'em to tear th is placedo wn , Juke tho ught. Save it fo rtourists. Th is shower 's so old - 1wouldn 't be surprised to findtbis 's where it all started - wherelife began .'

24 BIOPHYSICAL BASES

Chemical evolution

Matter becomes more complexwhen elements come together toform compounds. Atoms of oneelement unite with atoms ofother elements to form a newunit of matter - the molecule.The study of how elementscombine to form compounds iscalled "chemistry". Compounds,too, vary in how simple orcomplex they are. Numbersof single elements join, but thelimit of instability crops upagain. Compounds of simpleelements can only go so farbefore they become unstable. Atthis point instability is sur­mounted as single elements start

Molecular evolution

Organic compounds are of greai:concern to us all because foodwe eat is made of organic com­pounds ; also, fuels - coal, oil,wood - are organic. But othersstudy complex organic moleculesfor the sake of basic science.They presume that the simpleprotein substance emerged fromamino acids and that throughoutthis time these molecules evolved,assuming many new forms and

Life created in the lab

There was a time when everyone'sidea of a mad scientist was aperson trying to create life in atest tube. But for decades manytough-minded scholars andtechnicians have been workinghard to do just that - generate

to combine with existing com­pounds - and compounds com­bine with other compounds.

Molecules that contain carbonoften bind together in largegroups or chains to which mole­cules of simple compoundsattach themselves . Vast chainsand networks of molecules areformed in this manner. Thesecarbon compounds are called"organic compounds". Theirstudy is, of course, the subject oforganic chemistry.

Compounds that containhydrogen and oxygen canbecome monster size, highlycomplex organic groups. There's

becoming more complex. ;f hisprocess, called "molecular evolu­tion ", generated the first primi­tive cells that led to the contem­porary cell's basic unit of life'.

Molecular evolution: evolutionof the molecular structure.

life - trying to chart the likelycourse or courses of molecularevolution . These scientists mustkeep their methods simple ­processes that involve heat,elements, and water and othercompounds that were around

no theoretical limit to howcomplex they could get - yetthere seems to be a practical one.When they grow too large theytend to break apart - instability.

• 8 Atoms of different elementscome together to form a newunit called -------

• 9 The most complex chemicalcompounds are called

compounds.They always contain____. When they alsocontain and____, they have notheoretical Iim it to size orcomplexity.

.... , . .Why are organic compoundsof interest to all people?Why are organic compoundsof interest to scientists whoare trying to pinpoint theorigin of life?Thought question: What areliving things made of?From what organic com­pounds are protein sub­stances made?Define molecular evolution.

when the earth first formed. Ithas to be an open system, too- no pressure cooker or otherfancy gear. Nature didn't have it,so neither can they.

From what they've learned, itlooks like the stages of this

CHAPTER 2 BIOPHYSICAL STRUCTURE 25

evolution must have gone some­thing like this: first, simple non­organic compounds formed intoorganic compounds - organicmass . As the organic matterbecame more complex, it yieldedthe first amino acids - at firstonly a few, but then as many astwenty or so types or kinds. Theamino acids combined to formthe protein-like substance, orproteinoid - the forebear of allprotein . AU of these steps havebeen done in the lab under thesame conditions as must haveobtained on the new planetEarth.

The newest finding comingfrom the molecular evolution labis the formation of cell-likestructures from proteinoid . Onetype of these cell things (there

Nature never sleeps

Still the microsphere just isn't atrue cell . No one's satisfied sofar. So it's back to the lab for themolecular evolution bunch, totry again . Meanwhile , in a dampdump of black rock near avolcano in Hawaii, and in per­haps thousands of other places,the raw stuff that life 's made of

are several types of protocells, asthey're called) is a microsphere .Microspheres appear to do mostof the same things cells do,although not always in the sameway. They look like cells j littlespheres with an outside mem­brane that encloses them . Theygrow until they reach a matureform. But do they reproduce ­and do they move?

There's no doubt that micro­spheres help make more of theirkind. They need more assistance- more ready made substancesand intact energy from theenvironment - than cells we'reused to dealing with. Yet themicrospheres are and must beconstant midwives in the process.Without their effort there'd beno crop of little microspores,

is forming.This should remind us that

there 's one great differencebetween the lab and nature. Onlya few labs are working on theproblem of molecular evolution- a few dozen quite humanpeople. They have to stop work

who do , by the way, grow up to

look like their parents . Move­ment has been noted in micro­spheres, and there's some reasonto believe this movement isdirected, not random - asthough they're moving toward oraway from something.

-15 Briefly sketch the variousl ikely stages of molecularevolution.

-16 What is the forebear ofmodern protein called?

-17 Name one type of modelcell (protocell) produced inthe lab. What function doesit perform?

to care for their families , to eat,to sleep. Nature has thousands oflabs , ten million hands, and allthe time there is - and naturenever , never sleeps.

-18 How do nature's experi­ments differ from ours?

SINGLE CELL REPRODUCTION

The cell

Nature just keep s it up . It willsooner or later produce the mostcomplex microsphere , or otherprotocells , it can ~ then instabil­ity. Microspheres as such canonly go so far, get so complex.

But a lot could happen alongthe way. For instance, every oncein a while a special microsphereis going to pop up - one with aslightly different structure, astructure th at allows it toreproduce in a more effic ientway and not depend so much onthe outside for help - one whosereproduction process could bemore self-contained . But whyshould this matter?

When we're talking about th emost simple cells it probablydoesn 't. When a cell reproduces,it produces a new unit of lifethat is basically identical to itsparent self . No new cell is everthe precise copy of its parent.But then - when such a simpleform of life is concerned ­when it is made of such a smallnumber of simple parts - thereare only a fixed few ways anoffspring could differ from itsparent .

This isn't true when morecomplex cells are concerned . Theoffspring of a complex cell could

differ a great deal , for there'smore room for all kinds of thingsto happen . All the fine complexstructure of the parent could belost . Fickle fortune would thuslimit th e chance for complexityto maintain - and build acrossgenerations. There it is again ­up pops the devil - instability,the arch-enemy of complexity.

-19 We don 't have to worryabout simple cells being toodifferent from their parents.Why? This doesn't hold truewhen cells become morecomplex. Why not?

CHAPTER 2 BIOPHYSICAL STRUCTURE 27

The gene

But if chance keeps doingcomplex cells in, maybe thissame chance will create a cellthat has a new structure : somegimmick that acts like an insur­ance policy -limits chance,protects the complexity that onecell has and makes sure its heirsget it. This is exactly whatdid happen. At some point inevolving, a cell hit upon a struc­ture that acts to keep the formmore or less constant fromparent to offspring. This struc­ture is called a "gene". A gene isa substructure of the cell. It wastalked about for a long timebefore it was found andanalyzed.

Gene: substructure of a cell thatfunctions to maintain more orless constant form or structurebetween parent and offspring.

It's the DNA you've heard somuch about - deoxyribonucleicacid - simple molecules thathook one to the next in a chainor thread. Two such threads formside by side in a helix or spiralshape - the "double helix". It'sthis double helix structure that'sthe gene . In transferring struc­ture , order of the molecules ofthe parent cell is kept intactin the offspring. Of course , it'stransferred from parent tooffspring during reproduction.

The gene governs things like size,shape, and other features of theoffspring - tending to keep theoffspring like the parent.

-20 There's a feature that savesthe cell from instability;how does it work? What isit called?

-21 Define gene .-22 What is a gene constructed

of? Give initials. Give fullname.

-23 Draw a double helix.

The gene and mutation: nature's one-two punch

Sometimes there's a change in thestructure of the gene - the waythe simple building blocks are ar­ranged on the two threads. It canhappen to a parent when thingslike severe temperatures, contactwith harsh chemicals, or strayrays make contact with a cell.This change in the structure ofthe gene may change futuregrowth of the parent cell butmost important is the fact thatit's passed on to the offspring.Since the gene governs what k.indof structure the cell will have,the new cell will turn out some­what unlike other cells of itsspecies. A change that resultswhen the structure of the gene isaltered is called a " rnu ration"

Mutation: change in the compo­sition of the gene that resu lts inaltered structure in offspring ascompared to the parent.

The one-two punch of thegene and the change allowed bymutation are a tough pair tobeat. Both work to create cellsthat are ever different, unique,complex. Genes keep complexity(once it arises and proves to helpthe cell survive) constant.Meanwhile, mutation keeps onmaking subtle changes in theoffspring that'll be passed on ifthe offspring survives longenough to reproduce. In this

way mutation keeps polishing,making the species better able tosurvive.

It was without doubt thehand-in-hand work of the geneand mutation that beat theinstability trap . It cleared theway and caused life to explodeon the small planet Earth. It wasthis move that prepared the wayfor great creatures - the humanamong them - to evolve.

-24 How do genes and mutationwork to provide greatcomplexity?

-25 Define mutation.

28 BIOPHYSICAL BASES

THE LIFE EXPLOSION

The Glop That Kidnapped Kalamazoo

The guard sat at the metal desk eating a sandwich and reading anewspaper; beyond him, the thick lead-lined door that led to theplutonium vault. More than a ton of the awesome stuff was keptthere. The guard was not destined to dine alone that night. For atthat very instant, the "Glop" - slimy freak from the swamp - oozedforward. Bigger at this moment than a small truck, it would grow tothe size of a football field once it devoured the plutonium feastinside. Meanwhile, the guard, unknowing, with no hint of the gooeydeath that stalked him, started to nod. A ray of gray, viscousmatter flowed under the door, a pseudopod that belonged to theGlop.

"Look out!" Red bellowed . "The Glop's put out a testicle!"Down the row Liggit, Ragsdale, Curly, all guffawed.

"No man - the word's 'tentacle'," Curly rumbled in a low-pitchedvoice .

Friday night at the campus flick. Twenty-five cents and a studentI.D. got you in. Half the football squad was there, Juke Jacksonamong them.

"Hey, Red . That the woman you been messin' round with downthere?" Juke asked .

~~S! g~~!~~Q !9 ~~~ ~h9 !E ~~~ J~!~~ ~~~ !~!~!~B ~~9!:!!: "Qh ­yeah, that one. We went to the same high school. Crystal Burke. Inthe green - that who you mean?"

"That's her. What about the one sittin ' by her? You know her?""Met her once when she's with Crystal. Name's Mae. Mae

Robinson. She's cool okay, but she acts a little uppity.""Yeah?" Juke said.Just then the final reel began, the suspense-filled climax of "The

Glop That Kidnapped Kalamazoo".

Limit of the single cell

Thus, single-celled creatures found a new function made possible bythe structure of the gene . They could pass on new structure tooffspring. At the same time cells retained the tendency to mutate.This meant that some offspring would have structure that differedslightly from the parent. In many cases this made their chances to

survive far better. With these two great skills there would be no

CHAPTER 2 BIOPHYSICAL STRUCTURE 29

stopping this single-celled life from taking new shapes, forms, andacquiring new functions. They would venture as far and as wide aslimits would allow, moving ever more toward complexity. But aboveall, these single-celled creatures would endure. They seemed to have ameans to second guess nature - a ready counter for its cruel whims.It didn't seem to matter what new challenge the environmentmustered - changes in heat, cold, shortage of food, an influx ofcaustic substance into the life space. Somehow the creature or itscousins - some number of its kind - survived. These mutants werefor the most part just like their fallen kin. They differed only slightly,but differed enough in ways that mattered in survival.

The proof that these creatures were hardy and robust is seen in thefact that they are with us today in great sc·ope and number. They arecalled "microorganisms".

Micr.oorganism: simple life forms; often single-celled creatures.

Some microorganisms are helpful to humans. They degrade wastes,turning them into rich soil, help convert milk into cheese, fruit juiceinto wine. But some are a curse. We call these germs. They invadeour bodies and cause disease and death.

But what about the "Glop" - the single-celled creature that"kidnapped" Kalamazoo - worked complex vault locks, outwittedan entire army, humbled a thousand computers with its lightningfast logic? Need we fear such a mutant? No. Not at alL Such a single­celled marvel just couldn't be. For one thing, a single cell that largewould have a tough time moving fuel in, and just as tough a timegetting wastes out. The point is that there's a limit to the numberand kind of functions that can be performed by a single cell. Thecomplex functions the Glop performed simply couldn't be donewithout more moving parts, sensors and other structural features thatcouldn't be packed into a single cell - instability again, the end ofthe line for the single cell.

-26 In what sense do single cells second-guess nature?-27 What is a microorganism?-28 Why is it impossible for single cells to develop the highly

complex functions often credited them in science fiction movies?

30 BIOPHYSICAL STRUCTURE

ORIGIN OF MULTI-CELLED CREATURES

Cells - the building blocks of life

There's a limit to what a single'cell can do - a limit to complexity- a point of instability. But whatabout many such cells taken as awhole? Think of a cell as a brick.A group of bricks apart fromeach other are still just bricks.But when they are fastened toeach other - fitted - theybecome something else - assumenew function. They become awall, ahouse, a walkway. Cells aremuch the same. When they'reput together, a new structure canoccur - the old limit to

complexity is gone.It often works out that cells

that live together have a betterchance to survive than those whogo it alone. Cells at the center ofa cluster may grow larger andstronger than those on theoutside. Outside cells get the fullbrunt of harmful stimuli ­friction, cold and heat, and strayrays that damage structure. It'sonly at the expense of theircousins, pushed outside, that theinside cells, shielded and safe,reproduce to keep the species

alive. Does nature in its"wisdom" provide that someshould die so that a greaterpurpose will be served? No suchthing. It just happens that greatercomplexity pays off sometimesand up to a point.

-29 Why would cells ever beginto exist in clusters orgroups?

-3D What factor tended to give acluster of cells an advantageover single cells in somesituations?

Cell differentiation

CHAPTER 2 BIOPHYSICAL STRUCTURE 31

Cells that congregate, even join,are still just cells - they functionthe same, have the same needs aswhen they were loners. And, ofcourse, one feature that all cellsin the cluster retain is the abilityto mutate. As at other levels, thisprovides the way for greatercomplexity.

Suppose two cells exist side byside. They both need oxygen toburn fuel and to stay alive. Theyexpel carbon dioxide as a wasteproduct. But oxygen is in shortsupply - hard times are upon

them. They both scrape through- live just long enough to repro­duce. One produces offspringjust like itself - oxygen eaters,givers of carbon dioxide. Theother cell gives rise to mutantoffspring, with a new structure.These mutants take in carbondioxide as waste. Just the reverseof their parent and of offspringof the other cell.

There should be no problem inseeing that if the two parent cellswere good neighbors, theiroffspring are going to be even

better ones. Each type of cellnow has a better chance ofsurviving because of the muta­tion. As long as they stay close,they 'Il have an edge on cellsthat don't have such helpfulneighbors. When two organismssurvive through such joint advan­tage it is called "symbiosis",

Symbiosis: situation where twoor more organisms have a greatermutual chance to survive as aresult of the function theyprovide for each other.

32 BIOPHYSICAL BASES

Groups of cells thus have an even greater edge when some of themmutate and as a result of their new structure, provide a function thathelps all members of the group. Don't be fooled into thinking that acell mutates in a certain way because the group needs help andnature steps in to help.

There's no way to tell if a mutant cell's going to help or not.Sometimes mutants arise that hinder the group. They feed off thegroup, weaken it, make it work harder to survive - and they givenothing in return. Cells who exist at the expense of others and don'thelp out are called "parasites".

Parasite: an organism that exists because of functions provided byothers, but does not contribute to their survival.

Once cells join, and some mutate in ways that help the groupsurvive, the way is once again paved for great leaps in complexity Astime and mutation go on there's a trend for multi-celled organismsto grow cells that add to the whole. This process is called "celldifferentiation". But the key thing here is not that cells are different- not that they have a new structure. It's the fact that their newstructure allows them to provide a function that helps the wholesurvive. Thus, it's "differentiation of function" that we're reallytalking about.

Differentiation of function: as single-celled organisms develop intomultiple-celled ones, some cells develop specialized structure whichallows them to provide a function that helps the total organismsurvive.

-31 When a cell or other creature mutates in such a manner that itand another creature have a greater chance to survive, this iscalled _

-32 When a cell or other creature mutates in such a way that itmakes use of function provided by others but does notcontribute to their survival, it is called a _

-33 Define symbiosis. Define parasite.-34 Define differentiation of function.

CHAPTER 2 BIOPHYSICAL STRUCTURE 33

Centralization of function

Before they joined the club - became a multi-c~lled organism ­single cells used to absorb fuel, gasses, and other things they neededdirectly from the life space that engulfed them. Wastes weredumped into the same medium. In complex organisms, single cells nolonger do this for themselves. Fuel and oxygen are delivered byorgans and physiological systems - clusters of like cells that havedifferentiated and are now equipped to serve that function. Forinstance, when it was a loner a cell had to detect, and then moveaway from, harmful stimuli. Now when contact is made a specialsystem of differentiated cells (nerves) carries the stimulus to a centralarea (the spinal cord or brain) where it's transferred to muscles(cells differentiated to produce movement) that transport the entirecomplex of cells out of danger.

Thus, as multi-celled creatures become more complex, we finddifferentiated cells form substructures called '.'organs". Organs inturn connect to form "physiological systems". Special functions thatcells provide are thus centralized. They've evolved at new locationswithin the creature that seem to serve all cells best - "centralizationof function ".

Organ: substructure of a complex creature where cells form togetherto provide a function or functions that help the entire organismsurvive.

Physiological system: group of organs and supporting structures, thatprovide a special function for a creature.

Centralization of function: asmulti-celled organisms become morecomplex, cells specialize in a new function, and give up old functions.Functions given up are taken on by other cells specialized in thosefunctions. Cells that provide like function tend to be located atplaces in the organism best suited to serve the whole.

-35 What is an organ? Define.-36 What is a physiological system? Define.-37 Define centralization of function.

34 BIOPHYSICAL BASES

COMPLEXITY AND MUTATION IN MULTI-CELLED CREATURES

The end of mutation

In the first part of this chapter we said that the gene acted tomaintain a level of complexity across the generation gap. If a cell gotto the point th at it was making out pretty well , it'd be too bad ifchance would wipe it all out. The gene kept this from taking place. Itkept the structure of the offspring very much like the parent's. Butthere was still room for change - through mutation. The problem isthat there's no way to tell if the new structure will help or hindersurvival. If it hinders, the cell could die or just produce feweroffspring, and lose out in that manner.

But if we're talking about one cell, what's the worry? What's onecell more or less? Those that didn't mutate, or those that changed inways that helped or at least didn't hurt chances - will survive.There'll be enough of them so that the species goes on. But as singlecells combine to form more complex forms - as cells are differen­tiated and functions centralized - mutation gets a little risky. Justthink of a creature lucky enough to have cells differentiated to forma liver. A liver's a fine piece of machinery - it sifts out poisons, andprovides other functions that help all the cells survive. Then one fineday a "rebel" liver cell isn't content just to stay a liver cell - it wantsto be something else. It mutates to become a skin cell. Skin cells

rt~rgg1:!£t f~gl ~!!g ~rtf!y ~gg!! fh!!!s~ S~f 9~f 9f h~!"!~: Th~ !"!~~fthing you know, the creature's liver turns into a fingernail - or abig toe . You can see that wouldn't make the creature - or the restof the cells - very happy. As a result, when creatures becomecomplex, cells don't mutate so easily. And as you might suspect,more complex cells tend to mutate less often than simple ones. How?Because complex cells don't reproduce as often. Less chance formutation.

CHAPTER 2 BIOPHYSICAL STRUCTURE 35

Law of Complexity and Mutation: as multiple-celled creatures tendto develop complex differentiated cells and systems of centralizedfunction, mutations become less likely.

Thus, when complexity reaches a certain point, the samemechanism that created that complexity in the first place ­mutation - threatens the creature. Instability again! When this levelof complexity is reached change must occur more slowly - not beso drastic as mutation might allow.

Mutation had to go - and so it did. The human as perhaps themost complex model nature's made to date, is a case in point.Humans have specialized cells, organs, systems and central functions.Yet, for all the trillions of complex human cells, mutation is a rareevent.

But without mutation, how can the move toward complexity goon in humans and other multi-celled creatures? Or does it gonowhere , is this the end? Have we reached the final limit - the finallimit this side of instability?

-38 Mutation is always good for the creature. Discuss.-39 Why is mutation a problem with complex organisms?

-40 What would happen to a complex organism if mutation weren'theld in check?

-41 What is the law that states the relationship between complexityand mutation in complex organisms?

-42 Define the Law of Complexity and Mutation.-43 How common is mutation in human cells?

Asexual and sexual reproduction

The storyline was plodding, the dialogue stilted, the acting badbeyond belief - and as Mae knew from the biology course she'd hadat Christian College, there were downright errors in the biologicalfacts portrayed. The movie was so bad, it might well become aclassic. Students roared loudest at the clumsy attempts to lace ascene here and there with sex. At one point the hero was forced totear away the heroine's lab smock, saving her from a Glop spore thathad taken root on her bosom. This contrived bit of near-pornbrought the house down, with hoots, yells, and whistles.

Sex, Mae thought. Why are people so intrigued by it? For othercreatures it's only a very· minor part oflife; something they do toreproduce. Some don't need sex at all; they reproduce without it ­do it all themselves; asexual reproduction it's called. Suppose humanswere tbat way - asexual reproducers. Now that would be something!What would the filmmakers do then? For that matter, what aboutcommerce? Ad agents would have to find something besides sex tosell their wares - it could wreck the economy!

***Indeed, reproduction need not involve sex. All the reproduction

we've talked about thus far has occurred without it - "asexualreproduction", as it's called.

Asexual reproduction: reproduction process that produces anoffspring with one parent.

In asexual reproduction, the creature produces offspring withoutjoining with another creature. The most common form of asexualreproduction is called "mitosis".

Mitosis: asexual reproduction where the creature divides to form twoidentical organisms.

CHAPTER 2 TURE 37YS ICA L STRUCSIOPH

But humans and complex species reproduce themselves through"sexual reprod.uction ".

Sexual reproduction: reproduction process where offspring areproduced with two parents.

To a non-partial viewer, sexual reproduction must seem like a greatdeal of bother 'When compared to the asexual act. It requires thattwo creatures of life spaces that may differ to some extent great orsmall, must meet and spend time together. They must also producegerm cells and in some way insure their fusion into a single cell .The whole thirng would be much simpler to do at leisure and alone .Then why have complex creatures evolved in this manner?

-44 Define asexual reproduction.-45 Define sexuel reproduction .-46 What is rruitosis? Define.

CHAPTER 2 BIOPHYSICAL STRUCTURE 39

Sexual reproduction and complexity

We've pointed out in a past section that mutation isn't likely to yielda good outcome when the creature is a complex one; one with organsand physiological systems that must all work in concert. A mutantcell could reproduce to form a mutant organ, giving up old functionin the process, and leaving the rest of the creature in the lurch. Theentire mass of cells - the creature itself - would perish. Again, aswe've pointed out, when creatures therefore reach a certain stage ofcomplexity, mutation becomes a rare event.

But this poses a problem. If the environment were to change in amanner that was hostile to the species, there would be no mutants ­no creatures who could survive. The trend toward new structure,toward new complexity, would have ended as the power to mutateceased. All creatures would have long since developed identicalstructure - identical strengths and faults.

It's just this problem that sexual reproduction gets around. Withthis type of reproduction, a new level is reached; the way is clearedfor further complexity. Human sexual reproduction shows this quitewell. Sperm are released in the medium of fluid that is the majorpart of male reproductive matter, semen. A sperm is not an adequatecell, as it WIll disintegrate unless it finds a partner cell. When thesperm makes contact with the female reproductive matter, the egg, itpenetrates, the egg and sperm are joined. The two cells combine toform a stable cell. The entire structure of the offspring will growfrom this single cell. But what will the structure be like?

Egg: female reproductive cell that will unite with male sperm to forma new creature.

Sperm: male reproductive cell that will unite with female egg to forma new creatu fee

-47 Define egg.-48 Define sperm.

40 BIOPHYSICAL BASES

The gene lottery

We learned when dealing withsimple creatures that structure iscontrolled by the gene. Inhumans the gene likewisecontrols structure. A single genegives rise to a discrete feature ofstructure such as eye color, hairtexture, size and shape of limb,etc . Dozens of genes arecontained in a kind of genepackage called a "chromosome".

Chromosome: package thatcontains genes; each human cellhas 46 chromosomes, half ofwhich are represented in re­productive cells (sperm oregg).

A sperm or egg is supplied withhalf (23) of each of the donor's46 chromosomes. The exact 23chromosomes the sperm or egg

. --will have of the possible 46 isgoverned by chance - there's noway to know in front. Eggs andsperm are formed when thecomplete reproductive cell splits.Each sperm and egg is given halfof the complement of chromo­somes. This splitting of the

reproductive cell is called"meiosis' '.

Meiosis: the splitting of thehuman reproductive cell to formsperm and eggs with half (23) ofthe full complement of chromo­somes of the parent.

In this sense sexual reproduc­tion is a sort of biological lottery.The mother and father each selecthalf of their genes in randomfashion and toss them together.The offspring receive their geneticcomplement from these two ran­dom selections.

It's clear that sexual reproduc­tion is a good system. It givesplenty of room for furthercomplexity. By sampling onlyhalf the genes from each parent,creatures with features and

structures never seen before canwell occur. Sisters and brothersmay share certain features, butdiffer greatly in others. Only inthe rare case where a fertilizedegg breaks into two or moreseparate cells (forming ident icaltwins, triplets, etc .) do creatures

have the same genes, andtherefore the same structure.Aside from this no two are alike.A new threat from the environ­ment is now more likely to findsome who survive it.

Mae failed to see the survivalfeatures of sexual reproduction.It isn't just a new way to repro­duce that humans just happen tohave acquired. It's a giant leapahead, one that beats theinstability trap of mutation, andprovides for complex structure .Without it the human couldnever have evolved.

-49 Define chromosome. Howmany does the human have?How many of each partner'sare present at conception?

-50 Define meiosis.-51 How do meiosis and mitosis

differ?-52 In what sense can concep­

tion be thought of as abio logical lottery?

-53 Sexual reproduction has nogreat advantages over asexualreproduction. Attack ordefend.

CHAPTER 2 BIOPHYSICAL STRUCTURE 41

CONCLUSIONS - THE GREAT MUTATION

Sid looked over at Jukewho wasnow heavy into the books,studying. Sid envied Juke at thismoment. He wished he could getinto his studies, but somehow itjust wouldn't work. He keptthinking about the girl he'd metin physics class. Dawn - DawnBaker. Sure would like to get adate with her - but how? Can'tjust walk righ t up and ask her.Maybe Juke could give me somehints.

"Hey Juke .""Yeah , man.""How do you go about asking

a girl out on this campus?""Out?" Juke said."On a date.""Oh. Ask her, man. Jus' walk

right up and ask her.""I don't know. I don't know if

I'm h~f fy~~: ! Eh!~~ ~h~ 89~~ !9fbig guys with muscles, goodlooks, flashy - you know."

"Oh ," Juke said. "Only onething to do then."

"Yeah! What is it?""Mutate, man.""Mutate?""Sure, mutate." There was a

long pause."Thanks a lot, Jackson."Muffled laughter came from

behind Juke's book.

***We've come far in this chapter.

We started with the most simpleof atoms, hydrogen, showing

how it gained step by step incomplexity - but that complex­ity at that level ended whenstructure reached the breaking­up point - so complex that itbecame unstable. This sametheme was played upon atchemical, molecular, cellular,multi-cellular, and complex­creature levels.

But our account wouldn't becomplete if we didn't mention aquite special mutation thatoccurred somewhere along theway. The structure that resultedis of utmost concern for thesurvival of all higher creatures,and of the very greatest concernfor humans . It deserves to becalled the "Great Mutation". Thechange in structure that itproduced allows creatures to

~~~r~ ~~ ~h~!!B~~ !!! ~h~!~surroundings, even those that areextreme and happen all at once.Creatures with this structure canadapt without mutation orbreeding - each creature doingso within its own lifetime. TheGreat Mutation occurred, and atonce aU creatures with the newstructure gained a vast edge onthose without it . The functionthis structure allowed is calledlearning. In the next chapter wewill take an in-depth look atthe anatomy and physiology thatallow us and similar creatures toengage in this fantastic process.

II TEllPIYIIILIGIIALPRIIEII,IEI

INTRODUCTION

There are one hundred trillion cells that make up the human body.All of these came from the single cell formed by the union of asperm and an egg. But there's more to the feat than just the simplesplitting and resplitting of cells . As the embryo grows, cells emergeth at are quite unlike that first cell. Some form nerve and brain tissue ,others hair and skin, st ill others organs, glands , and blood vessels ­billions of years of evolution crammed into one small cell. In thischapter we'll attempt to cover the high lights of those aspects ofhuman structure and function that relate most to behavior.

STRUCTURE AND FUNCTION

There are, of course, many things we could observe when we study lifeforms . Just dissecting them to learn their parts and how they're puttogether is both an important and respectable pursuit. But this alonedoesn't seem to make most people happy for long. Sooner or laterthey get around to asking: "But what does it do?" They want toknow about function. The study of the gross structure of the humanbody is called "anatomy"; the study of its function is "physiology".

Anatomy: study of the structure of plants and animals.

Physiology: study of the function of living things and their organs.

Many structures or substructures may take part in providing afunction. For this reason physiologists speak of physiological systems .A physiological system consists of a group of structu res that arerelated in that they work together to provide a function or functions .

• 1 Define anatomy.• 2 Define physiology.• 3 Review: Define physiological system .

CHAPTER 3 PHYSIOLOGICAL PROCESSES 43

SIMPLE STIMULUS TRANSFER, ABSORPTION, AND TRANSFORMATION

Simple stimulus transfer

As we pointed out in the last chapter, the first multi-celled creatureswere scarcely more than globs of single-celled organisms. Are wewrong to call such a loose conglomerate of cells a creature? Perhaps.Still, they lived and thrived because they were a unit, having advan­tage in some environments over single-celled structures . But if cellslive as a unit, it follows th at at some point they started to respond asa unit. How did this come about?

Think of such a clump of cells adrift in liquid space - all around itstimuli - energy of many forms and in many strengths. At thisinstant let's say a sharp piece of rock or harmful chemical makescontact somewhere on the outside surface of the group . How can thepresence of this stimulus affect other cells, cells not making contact,cells far removed from the scene?

If contact is with a rock or other solid object, then the mechanicalforce of the contact - kinetic energy - would be transferred fromcells at the impact point to the cells touching them , and so on downthe line. As you can see, this doesn't require that cells react or even

g~ ~Ey~: HYY9~!9 YY9E~ j~~E ~~ yy~!! yyjEh g~!!~ 9!: ~ g!!!!~E9 E~g!~: 9E ~

row of dominoes.There exist today groups of single cells living together and

responding as a unit to events in their life space in just such a way.But problems arise when we rely on such a simple system. Energy islost as it passes through and between cells - it decays quickly anddies. If the cluster of cells is too large, those furthest from the pointof contact may never get the message. The result - a creature thatdoesn't have itself together. Time of transfer is also a factor. Survivalcould well depend on a quick response to harmful stimuli or thepresence of fuel. Too slow could be too late - the food gone, thecluster destroyed or engulfed by a predator. A better means ofstimulus transfer would have to evolve if multi-celled creatures wereto grow larger, use their many cells to advantage, and develop morecomplex functions.

Stimulus transfer: conduction of a stimu Ius energy from one part orstructure of a creature to other parts or structures.

• 4 Define stimulus transfer.• 5 How might the effects of contact with an object on the part of

some cells be transferred to the rest of the cells in the group?• 6 What two problems might the transfer method described above

present?

Absorption

We and all other creatures areimmersed in a constant bath ofenergy - energy of many kinds,forms, and strengths . We callthese various energy forms"stimuli" when we talk abouttypes of energy and the effectthey have on living matter.

Stimulus: any event in ourphysical world.

A stimulus must first be ab­sorbed before it can affect artyother substance - living or not.When a stimulus is absorbed itchanges the structure of thematter it impinges on, altering itsphysical or chemical make-up -

although the matter may quicklychange back once the stimulushas gone. Yet the change doesoccur - this is what is meant by"absorption".

Absorption: change in physical orchemical structure when a stim-u Ius makes contact.

Whether or not energy isabsorbed depends on its formand strength, and on the chemi­cal and physical make-up of thecreature it strikes. Once absorbed,a stimulus may fail to cause acreature to act. Whether or notresponses are produced by astimulus once it's absorbed

depends on a number of factors.The amount of energy absorbedis one. Others relate to thesetting - where the creature isand the task at hand. In abroader sense, both absorptionand action relate to the role thata given type of energy played inthe survival of the species as itevolved.

• 7 Define absorption.• 8 What is a stimulus?• 9 What current factors and

what species factors governwhether or not a stimulus isabsorbed by a particularcreature?

Receptors

CHAPTER 3 PHYSIOLOGICAL PROCESSES 45

Many kinds of stimuli - chemical,mechanical, sound and light waves- may relate to survival. Nostimulus stands a chance of beingeffective - causing a creature torespond - unless it is firstabsorbed . Whether a creatureresponds to minute traces of fuelor escapes from harmful stimuli(that could prove lethal in largedoses), depends very much onhow readily some of its cellsabsorb small amounts of theseforms of energy. As a result,complex creatures have evolvedcells with structures well-suitedto absorb certain forms of stim­ulus energy. Such specializedcells are called "receptors".

Creatures seem to develop

Stimulus transformation

When stimuli are absorbed they'rechanged into a new form of ener­gy; but not just any new form . Allstimuli must sooner or later bechanged or "transformed" in toforms that fit in with those spe­cial structures that have evolvedto perform stimulus transfer.

Stimulus transform: a change ofstimulus from one form ofenergy to another.

In the human, stimuli mustfirst be transformed into cherni­calor electrochemical energybefore they can be transferred.Transformation between the twomodes also occurs. A stimulus

receptor cells that are as good atabsorbing that energy as they canbe whenever being sensitive to aform of energy is crucial to

survival. For instance, receptorcells in the human eye willabsorb the very smallest packageor unit that light can be brokendown to - a single photon.

Receptors: specialized cells well­su ited to absorb certain forms ofenergy.

Some animals have receptorcells that are sensitive to stimulior features of stimuli for whichothers have no receptor cells atal1. Color is an instance of such astimulus feature. Humans, apes,

makes contact with the surface,is transformed into electro­chemical energy by a receptorcell lying nearby. This resultingenergy makes contact with agland that reacts by secretingchemicals - transforming theelectrochemical energy to chem­ical energy. Packages of chemicalenergy secreted by the glandcirculate through the blood­stream until they reach tissue oran organ that's sensitive to them.

Some structures making theinitial transform of stimulicoming from the outside arequite simple . Contact stimuli giverise to pain , touch, cold, heat,and vision; and chemical stimuli

and most birds have receptorcells that specialize to absorbdifferent wave lengths of light.Creatures that don't depend onfruits and vegetables for food, orcreatures that come out only atnight, don't seem to have evolvedsuch receptor cells - they don'trespond to color stimuli.

-10 Define receptors.-11 Review: When cells mutate

to take on a new function,it is called d off . How does th isrelate to receptors?

-12 How sensitive are humanlight-receptor cells?

-13 Cite an instance of receptorcells found in some speciesbut not in others.

are involved in taste and smell.They are all transformed at onceinto electrochemical energy byreceptor cells. Hearing requires acomplex transformation involv­ing many steps before stimuliare changed to electrochemicalenergy and transferred through­out the body.

-14 Define stimulus transform.-15 Into what two forms of

energy must stimuli betransformed before theycan be transferred through­out the human system?

-16 Give four examples of thesimplest form of stimulustransfer.

46 BIOPHYSICAL BASES

MAJOR STIMULUS TRANSFER SYSTEMS

There are two major human stimulus transfer systems. One, the"endocrine system", allows for more or less global contact with bodytissue by circulating packages of chemical energy in the bloodstream.Though contact with these stimuli is global, their effects can beselective . Organs and structures are sensitive to some of thesechemical substances and not to others .

Endocrine system: stimulus transfer system that involves chemicalsdispersed by glands into the bloodstream, where contact is made withother tissues through blood circulation.

The second important human stimulus transfer system is the"nervous system". It's made up of specialized cells that connect toform pathways that are enclosed or self-contained to a greater orlesser extent . This system is suited for rapid and selective stimulustransfer. One specialized part of this general. nervous system - thesomatic nervous system - connects the outside world to the brainand spinal cord - the central nervous system. The somatic nervoussystem then transfers stirn uli back from the central nervous system to

muscles that cause adaptive responses to occur. A special part of thenervous system - the autonomic nervous system - performs the taskof working with the endocrine system, allowing these two systems to

function as a unit .

Nervous system: stimulus transfer system made of specialized cellsthat form pathways through which electrochemical energy isconducted.

-17 Define endocrine system.-18 How do chemicals make contact with the body structures-

how are they distributed?-19 Define nervous system.-20 What transfer system allows for rapid and selective action?-21 What special part of the nervous system connects with the

endocrine system?

SMOOTH MUSCLE-GLANDS

BLOODSTREAM

ENDOCRINE SYSTEM

SKELETAL MUSCLE

ADRENAL GLAND

AUTONOMIC NEURONS

SOMATIC NEURONS

48 BIOPHYSICAL BASES

THE FUNCTION OF THE NERVOUS SYSTEM

Evolution and functions of the nervous system

If we are to understand the nervous system - the receptors, nerves,spinal cord, and brain - we must toss out much of the myth, the aweand presumed magic often ascribed to it. It sho uld be replaced byrespect - respect for the process of evolution that produced it . Weshouldn't forget that the nervous system does nothing on its own. Itis a passive guest , completely dependent on its host - the environ­ment . The environment produced it, and its functions pertain totallyto the environment. But wh at are these functions?

-22 What does it mean to say the nervous system does noth ing onits own?

Stimulus transfer

The primary fun ction of. the nervous system is st imulus transfer. Aswe've said earlier, the nervous system evolved because multiple-celledcreatures with such stimulus transfer systems could function better.Single-celled life forms have special substructures that absorb certainstimuli (receptors), and other substructures that cause movement(effectors) . Other structures suited for stimulus transfer developed at

the ~~~e time ~~ ~l:ll~irl~-c~!!e~ ()~B~!1is~s evolved ~ecer~()~ ~~!! ~ ~!1~

other special cells to provide movement. As a rule, creatures survivebest which have the most efficient receptor-effector bridge - oneth at reduces the tim e between contact with a stimulus and action.The simple chemical transfer system th at early organisms relied uponwas too slow and nonspecific. Yet , it was never gotten rid of - itpersists in the human as the endocrine system . It is also the meanswhereby energy is transferred from one nervous system cell (neuron)to th e next .

-23 What is the main function of t he nervous system?11124 What role does the chemical stimulus transfer system have in

human stimulus transfer?

CHAPTER 3 PHYSIOLOGICAL PROCESSES 49

Relay function

Stimulus transfer became a greater problem as species grew larger,evolving more complex organs and systems. Interplay among theseunits was crucial - but there was a limit to how much of a creature'stissue could be specialized for stimulus transfer. As a result, nervoussystems became better arranged . Cells came together to form relaycenters where stimulus transfer proceeded with greater speed andeconomy. In the human, the spinal cord and the greater portion ofthe brain itself are devoted to the simple routing of impulses.

Stimulus selection function

Once contact is made with a stimulus, a receptor has no choice butto absorb this energy. But responding to a stimulus isn't always best ­not at all times and in all settings. It would be well if there weresome way a stimulus could be selected from among the manyabsorbed at a given instant. A creature that is starving would farebest if it responded to the smell of nearby food, not reacting to otherstimuli that suggest the presence of harmful but far from lethalconditions.

The nervous system helps provide this stimulus selection function -

ma~iRg if li~ely fRaf stimuli most relevant £0 SUrvival are respoR8e8to. It acts in both direct and indirect ways to achieve this result.Some reflex movements reduce the strength of stimuli by blockingthem from reaching the receptor. When sound is too loud, smallmuscles that connect to the series of bones conducting eardrummovement relax. The same strength of sound stimuli produces lessmovement in the middle ear, causing us to experience less sound.Blinking or squinting our eyes in intense light also reduces stimulireaching receptors.

The nervous system acts on its own to select stimuli that areresponded to through a process called inhibition. Inhibition accountsfor the fact that we see objects with a very dark border which makesthem stand out against their background. Cells adjacent to the borderinhibit the production of electrochemical energy at the border - asthough no light at all was present in that region. Impulses going tothe brain are reduced to near zero. The result - a crisp and clearobject, distinct from the background .

50 BIOPHYSICAL BASES

Inhibition also occurs at relay areas and other large structures ofthe spinal cord and brain. For some parts of the system to functionat peak, others must remain idle. Centers in the brain not only helpdistribute inputs - they do so selectively, acting as gatekeepers. Thisis made possible through the complex interconnections among allparts of the nervous system.

Stimulus selection by the nervous system changes as a result ofpast rewards and punishers. Stimuli having little effect under onecondition gain great control as new experience dictates. Sights,sounds, tastes, and smells leap out at us after they've been linked tooutcomes that relate to our well-being, though in the past we maynever have noticed them.

-25 Why is stimulus selection a crucial function?-26 Give one direct and one indirect way the nervous system helps

provide stimulus selection function.

Arousal function

Sometimes it's best that even a weak stimulus input has the effect ofcalling many parts of the body into quick and intense action. Thenervous system provides for this arousal in two ways. The first

involves its action on ERe en80crlne system. One segment of ERenervous system - the autonomic nervous system (ANS) - connectsto the glands and major structures of the endocrine system. Irnpulsescoming from the ANS cause glands to secrete chemicals into thebloodstream. All tissues and structures are reached as blood circulatesand relevant organs can respond to the crisis.

A faster method of massive arousal of a short term nature isachieved by the structures of the nervous system itself. Alone andwithin an intact bundle ofaxons, one nerve cell supplies only a smallcontained current. But large structures of the brain have hundreds ofthousands of neurons whose single currents may sum together - theresult, a huge rush of electrical action that can flood into all structures- gross arousal in an instant. One part of the nervous system thatprovides the power for this massive call to arms is the reticularformation . It comprises what may be thought of as the inner core ofthe brain - a structure about the size of your little finger. It extendsup from the spinal cord into the deep center of the brain - a goodlocation to receive sensory input and to mobilize the entire brain .

-27 Briefly describe what's meant by the term "arousal function".-28 The nervous system creates arousal in two main ways. Describe

them.

CHAPTER 3 PHYSIOLOGICAL PROCESSES 51

Feedback

An event taking place on your scalp causes disturbance to nearbyreceptor cells. They respond, producing current that makes adjacentneurons fire, their impulses leading down the axon bundle to thespinal cord . Once there, impulses are relayed to a motor nerve thatservices arm muscles. You respond - you scratch your head. If youhit the right spot and the scratching works, the receptors that signaledthe disturbance will stop action. If not, they'll keep it up. Themuscles that controlled the response mayor may not be called onagain . This is a type of feedback, because in a sense, the muscle isinformed of its success or failure.

But there's one thing it wasn't informed of - what it did toproduce the outcome . If they're to work, muscles must not onlyrespond to inputs from other structures - they must also respond tothemselves . Evolution took care of this nicely by providing muscleswith small structures that generate current when they act . When amuscle moves, it acts not only in response to impulses coming fromother sources - it also responds to impulses produced by its ownmovement. This is another type of feedback .

Feedback from muscles is also crucial for other reasons. Movementfrom one muscle sends impulses that inhibit action of an opposingmuscle or other part of the body that would interfere with its actionand successful result. Much of the nervous system is devoted to

feedback function : 9rBaJ1s~ ~tl~~!~~: B!~!"1~~~ ~h~ !!!~f r~~~~ ~f ~h~brain itself, must come under the control of their own action as wellas the outcomes they produce - two types of feedback.

• 29 Describe at least two instances where feedback fu nction isimportant for muscle function.

52 BIOPHYSICAL BASES

STRUCTURE IOF THE NERVOUS SYSTEM

The neuron

The "neuron " iis a cell. It evolved to assume the special function ofst imulus transfer. It is th e building block of the nervous syst em .Neurons form merves, and the intricate structures of the spinal cordand brain. But" fir st of all, neurons are cells. They have cell mem­br anes enclosimg a nucleus . Th e nucleus and other structures burnfu el , keep the c ell alive, and produce other substances it nee ds tofunction.

Neurons conne in many sha pes and sizes. Som e, for instance, aredrawn out in long th in strands many feet in length . A sensory neuron- a single cell - goes from yo ur big toe all the way up to the middleof yo ur back. The long drawn-out part of the cell is called the " axon".It' s the part of th e neuron that pro vides a path for stimuli to travellong distances. Th e other end of the neuron has many tree-likebranches called! " de ndrit es". Impulses flow into dendrites, thentravel down the axon. Nerves are axons that run alongside each otherin bundles.

Nerves that nransfer sensor y stimuli to th e central nervous systemare called " afferent", or sensory nerves. They deal with the senses :hearing, sigh t , itouch , temperature, taste, and smell. " Efferen t ", ormotor neurons , provide transfer in the other direction. Impulsesfrom inner stnnctures are transferred to muscles , causing them tocontract, movimg some of the cre ature's body parts . Other neuronsare relays shunting impulses caused by outside stimuli to other parts,often to motor' neuron pathways that lead back out to muscles.These relay neutrons are sometimes called "interneurons". Theyconnect to oth.er neurons, making chain s or networks that are quitecomplex and whose function is only partly understood. The pointwhere neurons connect with each other is called a " synapse".

RECEPTOR CELL

MUSCLE

CHAPTER 3 PHYSIOLOGICAL PROCESSES 53

Neuron: cell specialized for rapid and far reaching stimulus transfer.

Axon: part of the neuron cell body that transfers stimuli across thegreatest distances.

Dendrite: that part of the neuron that receives a stimulus input.

Nerves: axons that run in bundles alongside each other.

Afferent nerves: nerves that transfer sensory stimuli coming from theoutside, to inside structures.

Efferent nerves: nerves that transfer stimu Ii to muscles or glands,causing them to respond.

Interneurons: neural cells that form pathways to serve a relayfunction in stimulus transfer.

Synapse: connection between two neurons.

Define neuron..... . ..... -What is an afferent neuron? An efferent neuron?What does an interneuron do?Define synapse.

SPINAL COLUMN

AFFERENT NEURON

EFFERENT NEURON

How neurons conduct

Receptor cells absorb stimuli, converting the stimulus energy into anew form - electrochemical energy. This energy contacts thedendrites of an adjacent neuron, causing this cell to send energydown its axon. This is nerve conduction. But what is the nature ofthis flowing energy and how is it produced?

Quite early in the game, workers found that an electric currentwas always present when nerves were active. At that moment inhistory electricity was a newly discovered miracle - something soamazing it just had to playa gre?-t role in the scheme of things. Whynot in the human nervous system? Nerves were merely wires carryingelectric current - the nerve impulse . This answer made most peoplefeel content about nerve conduction until a famous scientist namedHermann Helmholtz measured the speed of an impulse moving downthe nerve of a frog's leg. He found that nerve impulses traveled quiteslowly - from 2 to 200 mph - when compared to the speed of elec­tricity, 186,300 miles per second. It was dear that whatever theywere, nerves didn't work like wires, and nerve impulses weren't justelectric current. But why the current at all?

As we know today, each neuron is a sort of wet cell battery - inprinciple, not unlike the one in your car, with a positive charge on theoutside surface of the axon membrane, relative to the inside of thecell membrane. The difference in potential from outside to inside themembrane is roughly 1110 of a volt (70 millivolts).

This is how it is when a neuron is at rest. it wili stay that way untilsomething happens to the cell membrane - something such ascontact with chemicals or electric current - to change its permeabilityever so slightly. When this happens, the nerve fires . To "fire" meansthat positive ions come rushing through the weakened membrane andreverse the charge on both sides - making the inside positive and theoutside negative. This action affects the next part of the nerve,causing the same change in polarity to occur - then on it goes downthe length of the axon, a moving negative wave. Once the wave haspassed a point in the axon, the state of the axon behind it starts toreturn to normal. Positive ions from inside pass outward to restorethe outside positive charge . Within a thousandth of a second it'sloaded (back to normal), and ready to fire again.

-34 Why was it first thought that neural axons were like wires andimpulses electricity?

,- 35 Who first measured the speed of nerve conduction?-36 Describe the resting state, firing, and return to resting state of a

neuron.

56 B'IOPHYSICAL BASES

The All or None Law

Stimuli differ in strength as wellas in form. Further, strength orintensity is far from being aneutral or inert feature of stimuli ,as the effects a stimulus has onliving tissue depend in large partupon how strong it is. For thisreason, a creature has an edge insurvival if its actions are contro l­led by stimulus strength as well asform. But if this is to occur, stim­ulus strength must somehow becoded in neural action. How isthis achieved? This may appear asimple problem for someonewho's not aware of how neuronsconduct. "Nothing to it! A smallamount of a stimulus causes asmall wave of negative currentdown the neural axon - a largerstimulus, a larger current, and soon ." Quite simple. But there'sone problem: neurons don 't~ . ~ - l---~-- ---- ------- --- - - - - -

work that way. A neuron eitherfires - sending the largest currentit can muster down the axon -or it doesn't fire at all; andthere's nothing in between. Thisis called the "All or None Law"of nerve conduction.

All or None Law: neurons eitherfire as totally as they are capableor they don't fire at all. There isno graded response.

Yes, the All or None Lawholds for all neurons. But thereceptor saves the day - allowingthe strength of a stimulus to beretained in the nature of thenerve impulse. As we alreadyknow, receptors transform rawstimulus energy into electro­chemical energy. Unlike theaction of a nerve with its all-or-

none wave of curren t, receptorenergy is a graded electrochem­ical output that grows larger asthe amount or strength ofstimulus contact increases.

Receptor endings connect tothe dendrites of nearby neurons.If the current reaching its den­d ~ i tes is strong enough, a neuronwill fire, and then restore itself ­ready to fire again. All of thistakes only a thousandth of asecond. After firing, the neuronremains at rest until the currentcoming from the receptor isagain large enough to make itfire. More intense and lastingstimuli make the rate of neuronfiring increase, until, at last, it'sfiring as often as it can. Nosooner does it restore itself thanit's called on to expend its

~~~~8~: !~ ~~~2~r ~~!~ ~2~!Qresult in the neuron firing asoften as a thousand times persecond - if enough currentreached its dendrites . Lessintense stimuli and/or shorterlasting stimuli would produceless receptor current and causethe neuron to fire less often. So,the more intense the sti mulusthat reaches the receptor, themore current it sends to the den­drites and the more often theneuron puts out impulses.

But we often respond to moreintense stimuli than a singleneuron can code , or responddifferently to. What happensthen? Well, then the neuronswork together as a team. Whenstimuli become intense, groupsor nets of receptors converge onclusters of dendrites belongingto many neurons. As stimulus

strength at a point of contact in­creases or as the area of contactgrows, currents from increasednumbers of receptors come intoplay. These currents becomestronger as they reach the den­drites of the neuron bundle. Thiscauses the neurons to fire. As re­ceptor currents mount, moreneurons in a bundle join in untilscores are involved . This is called"recruitment". As more neuronsfire, the result is a nerve dischargethat's the summated total of thecurrent from all the singleneurons recruited.

Recruitment: as summatedaction of receptors grows, moreneurons in a bundle begin to fire.

Receptor currents also increase

an~ ftff~tt grt~!tr nHmB~r§ 8fneurons in a bundle as energycoming from the outside in­creases. The final upshot is that agreater amount of energy reach­ing receptors results in a greaternumber of neurons beinginvolved - all firing in terms ofthe All or None Law - but makinga total nerve discharge that keepsup with the strength of the input.

-37 State the Allor None Law.-38 What apparent problem

does the Allor None Lawsuggest?

-39 How can intensity of astimulus be coded by asinqle neuron?

-40 How is intensity and/or areaof stimulus contact reflectedwhere groups of receptorsand neurons are involved?

Synaptic transfer

CHAPTER 3 P~YSIOLOGICAL PROCESSES 57

As mentioned before, neuronsconnect to other neurons atspecial junctions called synapses .Transfer taking place at thesynapse involves a unique chemi­cal exchange between the axonof one neuron and the dendriteof another. Axons end in anenlarged structure called the endbou ton . The impulses are receivedby a special nodule on the adja­cent dendrite called the dendriticspine. End boutons contain manysmall island-like structures called

CON'CLUSIONS

In this chapter we've remainedtrue to the theme of evolution indealing with human anatomy andphysiology. Although we've paid

dus ft§ptet§ to ths humannervous system, we've nottreated it like some deity deserv­ing of worship. Instead we've

"synaptic vesicles". They releasechemicals when an impulsereaches the end of the axon.These chemicals or chemicaltransfer agents, as they arecalled, playa prime role insynaptic transfer. Some chemi­cals released by the synapticvesicles promote transfer acrossthe synapse while others retardit, or stop it altogether.

Synaptic vesicles: clumps ofmatter occurring in the end

taken a simpler view - that itrepresents a highly complex andefficient solution to the problemof putting a creature in contact

WitR iH eRVif8RffieRL As SUER, iE~sa fine piece of work, one slowlyand subtly crafted through eonsby the demands of survival. Now

bouton that release chemicalswhen an impulse comes downthe axon.

Transmitter agents: chemicalsreleased at the synapse thatgovern the nature of synaptictransfer.

-41 What are the synaptic vesi­cles? Define.

-42 Define transmitter agents.

we're better prepared to view thehuman in action , having at least apassing knowledge of inner struc­ture and function. It's time to

lss~ at 13eRavisf, aRtI RSW ifcame about.