Homan evolutionary biology

Human
Evolutionary
Biology

Human Anatomy and Physiology
from an Evolutionary Perspective

Everyone is interested in Human Biology.

This book is…
timely — there are no others.
up-to-date— it includes
discoveries of recent months.
complete—it provides an
essential overview as well as a
detailed explanation of human
body systems.
exciting— because it presents
a great deal of information in a
more meaningful fashion.
It will equally engross the
struggling biology student and
the educated layperson.

PRESS

Human Anatomy and
Physiology from an
Evolutionary Perspective

Anatomy and physiology permeate our daily

experiences from conception to death.
Biology holds the key to our love and hate,
health and sickness, reproduction and
infertility, terrible two‘s and adolescent
rebellion. Indeed, the study of human biology
opens the door to an understanding of life
itself. Despite many pieces still missing, the
overall patterns are clear—nature is prolific,
resources are limited, competition is fierce,
variation is inevitable. With only the most
fit surviving to reproduce, natural selection
brings about endless adaptive changes.
In his inimitably upbeat and irreverent style,
Dr. Arndt von Hippel demonstrates how
the latest scientific findings confirm a
tortuous progression of events from the
universal Big Bang to you. Dr. von Hippel is
an accomplished surgeon and popular
teacher whose three previous books were
enthusiastically received. Reviewers of those
texts commented:
“The style of writing is attractive, interesting
and clear… obviously the work of a very
practical man who has given a lot of thought
to all problems of thoracic surgery
management… over a very long experience.”
The Australian & New Zealand
Journal of Surgery
“…tout clair et coherent, susceptible
d'interesser tous les chirurgiens et les

anesthesistes reanimateurs…”
Annales de Cardiologie et D'Angeiologie
“I highly recommend this book…”
Annals of Thoracic Surgery

Stone Age Press

Stone Age

Arndt von Hippel

$29.95

Arndt von Hippel



Human Evolutionary Biology
Comments by reviewers of this text:
“The author displays an excellent talent for describing biologic
processes in easy to comprehend and interesting lay terms”
“…The level and quality of the physiology presentation is much
better than (in) any straight physiology text we examined.”
“…an admirably…functional approach which I heartily applaud.”
“charming and informative…”
“Reducing the human species to just one type of evolutionary form
is folly(!)”
“All necessary topics are covered… I believe the approach is
appropriate, even refreshing to someone like myself. It is droll and
sardonic… very readable… the level of detail…may be the

strongest aspect of this presentation. I enjoyed reading the text,
particularly its irreverent analogies… The continual discussion of
the selective pressure and its consequences on the genome and
reproductive success is the most successful part of the presentation.
Yes, by all means… a valuable addition to a modern human
biology course.”
“He is quite a good writer and I enjoyed a chuckle or two as I
read the manuscript. I got the sense of a “Fantastic Voyage”
approach… a very nice job of tying in the evolutionary connections… the integration of familiar examples…gives one a sense
that this material has some relevance to the real world.”



Human
Evolutionary
Biology
Human Anatomy and Physiology
from an Evolutionary Perspective
Arndt von Hippel

STONE AGE PRESS
Anchorage, Alaska


Human Evolutionary Biology
Human Anatomy and Physiology from an Evolutionary Perspective
by Arndt von Hippel
Published by:
Stone Age Press
1649 Bannister Drive

Anchorage, AK 99508
(907) 279-3740
Cover design: Leslie Newman
Book design and production: Newman Design/Illustration
Printer: R.R. Donnelley and Sons
Publisher’s Cataloging in Publication Data
von Hippel, Arndt, 1932–
Human evolutionary biology : human anatomy and physiology from an
evolutionary perspective / Arndt von Hippel.
p. cm.
Includes bibliographical references and index.
Pre-assigned LCCN: 94-067336
ISBN 0-9615808-2-8
1. Human biology. 2. Evolution (Biology) 3. Natural selection.
I. Title
QP34.5.V65 1995
612
QBI94-1508
© 1994 Arndt von Hippel. All rights reserved.
This book protected by copyright. Short excerpts may be reproduced without written
permission from the publisher, provided credit is given to copyright holder and
publisher’s address is included.
Stone Age Books are selected and published with care by Stone Age Press of Alaska.
It is the publisher’s intent to present significant material in a sturdy, inexpensive
and pleasing format that will assure Stone Age Press a good name and good will.
PRINTED IN THE UNITED STATES OF AMERICA


for
Marianne, Ted, Bill, Karin, Frank

and those yet to come


9.0122
Beryllium

12

Mg

24.312
Magnesium

6.939
Lithium

11

Na

22.9898

20

Ca

40.08
Calcium

19

K

39.102
Potassium

Sodium

4

Be

3

Li

25

54.938
Manganese

Mn

26
27
58.933
Cobalt

Iron

Co

55.847

Fe

28
58.71
Nickel

Ni

29
63.54
Copper

Cu

30

Zinc

65.37

Zn

5
6

69.72

Gallium

Ga

31

26.9815
Aluminum

Al

72.59
Germanium

Ge

32

Silicon

28.086

Si

14

Carbon

13

12.0111

Boron

C

10.811

B

7

74.922
Arsenic

As

33

30.9738
Phosphorus

P

15

Nitrogen

14.0067

N

8

78.96
Selenium

Se

34

Sulfur

32.064

S

16

Oxygen

15.9994

O

9

79.909
Bromine

Br

35

35.453
Chlorine

Cl

17

Fluorine

18.9984

F

4.0026

1.00797
Hydrogen

83.80
Krypton

Kr

36

Argon

39.948

Ar

18

Neon

20.183

Ne

10

Helium

2

He

1

H

PERIODIC TABLE OF THE ELEMENTS


vii

TABLE OF CONTENTS
PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv
PROLOGUE TO CREATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
Overview;… All Creatures Bear Evidence;… What Is Scientific Evidence,
And How Can We Be Sure?… There Are Thousands of Religions But Just
One Science;… There Is No Scientific Basis For Any Religion;… Religions
Lose Credibility When They Attack Science;… How Shall We Recognize
Scientific Truth When We See It?… A Never-ending Series Of Questions
Leads To New Scientific Discoveries;… Correlation, Causation, Anecdotal
Evidence And Biased Reporting;… So You Must Decide.
CHAPTER 1: THE BIG BANG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2
E = mc ;… Overview;… The Moment Of Creation—A Big Bang;…
Inflation Theory;… As Matter Cooled It Formed Simple Atoms, Some Of
Which Were Unstable;… Both Nuclear Fission And Nuclear Fusion Can
Convert A Little Matter Into A Lot Of Energy;… Proton Count Establishes
Atom Identity While Electron Count Controls Chemistry;… Only Simple
Atoms Resulted From The Big Bang, So Primordial Chemistry Was
Simple;… Stars Utilize Gravitational Energy To Repackage Protons And
Neutrons Within Heavier Elements;… Naturally Radioactive Isotopes
Release Star Energy At Predictable Rates;… Summary.
CHAPTER 2: BEFORE LIFE WAS CHEMISTRY . . . . . . . . . . . . . . . . . . . . 25
Overview;… The Origin of Life On Earth;… Prebiotic Earth;… Life Is
Water-Based;… Constant Molecular Collisions;… A Mole Is A Very
Specific Number Of Molecules;… Water Is Liquid Because… Acid, Alkali
And pH;… Oxidation And Reduction—Electron Donor Seeks Electron
Grabber And Vice Versa;… First Life Was Anaerobic;… Carbon Chemistry
Is The Chemistry Of Life;… Putting Out Fires;… Life Produces And
Depends Upon An Unstable Atmosphere;… The Elements Of Life.

viii

Human Evolutionary Biology

CHAPTER 3: THE GATHERING INFORMATION STORM . . . . . . . . . . . 47
There Were No Guidelines For Prebiotic Molecules;… Natural Selection
Chooses Without Caring;… Alive, Not Alive Or Dead;… Life’s Limits;…
Life Is A Bacteria-Based Show;… Sterility;… Inheritance;… Naked DNA
As Free Advice;… Protein-Covered Advice;… Parasitic Opinions And
Afterthoughts;… The Rising Information Tide Lifts All Life Before It;…
Advice Comes From All Directions;… The Path Not Taken;… Mind Over
Living Matter And Vice Versa;… Diffusion Of Information;… Gaia And
Homeostasis;… The Thermodynamics Of Life;… Life Is A Four Letter
Word;… Complementary DNA Strands Fit Together;… RNA Utilized U
Instead Of T;… Those 100,000 Genes Are The Real You;… How The
Modular Tools And Processes Of Life Evolve;… 100,000 Genes Are
Not Enough.
CHAPTER 4: ONE HUMAN CELL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Passing Your DNA Onward;… Semipermeable Membranes;… The
Corporate Cell;… Cell Components And Assembly: How You Produce SelfAssembling, Self-Sealing Cell Membranes In Your Watery World—I: In
Water, Fatty Acids Clump Up As Micelles;… II: Three Fatty Acids
Covalently Bonded To One Glycerol Form Neutral Fat (A Triglyceride);…
III: Cell Membranes Are Self-Assembled Phospholipid Bilayers;… IV: DNA
Determines Membrane Characteristics, Membranes Help Determine Which
Genes Will Be Expressed;… V: And There Is More To Life Than That;…
DNA And RNA Are Linear Nucleotide Polymers;… By Their Enzymes
Shall Ye Know Them;… Chromosomes Are Nucleoproteins;… Many
Introns Must Be Excised From Messenger RNA (mRNA);… Upon Release
From The Nucleus, Messenger RNA Is Translated Into Amino Acids By

Ribosomes;… Proteins Are The Ultimate Molecular Tools Because Of Their
Unlimited Variability In Size, Shape, Charge, Solubility And Allosteric
Movements (Ability To Change Shape In Response To Changes In Their
Environment);… Peptide Bonds Are Rigid Connections;… It Is Tough For
A Protein To Get Back Into Shape But DNA Does It All The Time;… As In
Politics, New Combinations Are Common, New Ideas Rare;… The Letters
Endure: The Patterns Pass;… Immortality Would Be Fatal;… Cell Imports
And Exports;… Diffusion, Osmosis And The Second Law Of
Thermodynamics;… Photosynthesis, Oxygen And Carbohydrates;…
Glucose, Glycogen And Osmosis.


Table of Contents

ix

CHAPTER 5: PROCESSING INFORMATION:
THE MULTICELLULAR ADVANTAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Life Stabilizes The Environment Which Enhances Life;… Life Feeds On
Life Which Limits Cooperation;… Multicellular Groups Self-Assemble;…
When Complexity Causes Information Overload, Specialization Can
Restore Productivity;… Employee Specialization Allows An Organization
To Process A Lot More Information;… Death Liberates Scarce Resources For
More Productive Use;… Your Specialized Cells Utilize A Great Deal Of
Information;… Cooperation, Altruism, Ethics And Morality Come About
Naturally In A Society Of Closely Related Cells (Or People);… Ethics Are
Situational;… All Humans Are Close Relatives.
CHAPTER 6: SKIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Skin Is Taken For Granted;… Your Skin Touches The World;… Hair;…
Epidermis;… Skin Color;… Dermis;… Heat And Fluid Losses Through

Normal And Damaged Skin;… Pimples;… Your Sweaty Hands And
Feet;… Modified Sweat Glands;… Local Heat Loss;… Humidity;…
Temperature And Reproduction;… Burns;… Skin Grafts.
CHAPTER 7: MULTICELLULAR MORALITY
BEGAN WITH COLLAGEN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Cooperation Created Fiercer Competitors;… Collagen Caused Kindness
Through Specialization Of Cells;… Collagen;… Good Proteins Come In
Small Modules;… You Are A Monkey’s Aunt (or Uncle);… After Life
Comes Glue;… Extracellular Space Can Be A Busy Place;… How Do Your
Tissues Hold Their Water?… Proteoglycan Is The Answer.
CHAPTER 8: COLLAGEN PULLS,
CALCIUM LIFTS, CARTILAGE SUCKS . . . . . . . . . . . . . . . . . . . . . . . . . . 143
A Skeleton Made Of Sugar Sucks;… A Flexible Water Skeleton That Can
Suck Or Blow;… Some Seek Shape And Shelter Within Their Own
Metabolic Wastes;… Your Dry Bones;… Shock Absorbers Reduce Structural
Stress;… Collagen Pulls While Cartilage Sucks;… You Were Patterned In
Cartilage;… Perichondrium;… Bone Formation;… Your Inner Rocks;…
Bones Rarely Break;… Bone Remodeling Reduces Risk Of Fracture While
Controlling The Calcium Concentration In Your Blood;… Avoid
Osteoporosis, Rhubarb And Spinach.


x

Human Evolutionary Biology

CHAPTER 9: YOUR HUMAN SKELETON. . . . . . . . . . . . . . . . . . . . . . . . 157
Life Depends Upon Instability;… Life Is Unstable At Every Level;… Your
Bones Are Unstable Too;… Using Leverage;… Your Skeleton Is Not Very
Graceful;… Location Is Everything;… Would Three Legs Be Better?…

Reproduction Matters;… Symmetry;… Weight And Balance.
CHAPTER 10: WHY MUSCLE? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
Information Is;… Marketing Your Message;… Move It Or Lose It.
CHAPTER 11: MUSCLE RULES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
The Muscle Arms Race Eventually Depends Upon Death;… On The
Importance Of Muscle For Coveting;… What Was The Question?…
Better Muscle Contraction Through Chemistry;… The Actual Machinery
Of Muscle Contraction;… Actin Holds;… Myosin Pulls;…
Ca++ Controls;… ATP Pays;… Overview Of The Muscle Contraction
Process;… Deathly Disorder;… Panting Repays Oxygen Debt To Muscle
(Via The Blood);… Getting Your Muscles To Do What You Want;…
Cardiac (Heart) Muscle;… Smooth Muscle.
CHAPTER 12: NERVE RULES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
Life Depends Upon A Separation Of Charges;… Transmembrane Ion
Gradients Mean Life: Life Means Work Plus Risk;… Nerve And Muscle
Cell Function Depend Upon Electrochemical Gradients;… Overview;…
Cycle I: There Are Several Steps;… Cycle II: How Does A Nerve Cell
Decide When Or Whether To Fire (Depolarize Or Discharge)?… Why Does
A Nerve Cell Transfer Its Message Chemically?… Cycle III: The
Electrochemical Events That Accompany Membrane Depolarization;…
+
+
Na Leakage Is So Exciting;… K And C1 Leakage Inhibit Neuron
Depolarization;… Calcium Channels;… Myelination And Saltatory
Conduction Helped Your Ancestors To Prevail.
CHAPTER 13: YOUR 100 BILLION NEURONS . . . . . . . . . . . . . . . . . . . . 205
There Is No Such Thing As Smart Enough;… Conflict, Competition,
Cooperation And Codependence;… Truth Is More Novel Than Fiction;…
Survival Of The Fittest Microcircuit?… Information Tends To Spread,
(And Also To Reduce Disorder—Take That, Second Law!);… Competition

Increases Wealth;… The Input Is Overwhelming;… So What Is
Behavior?… The Incredible Non-Shrinking Of Your Personal Program;…


Table of Contents

xi

What Can We Learn From Sensory Deprivation?… How About
Anesthesia?… Blocked Motor Output—Muscle Relaxants;… Mind And
Brain;… Your Central, Peripheral And Vegetative Nervous Systems Are
One;… Your Internal Display Is Subjective And Defective;… So Your
Behavior Is Often Weird;… And Possibly Ambivalent.
CHAPTER 14: YOUR NERVOUS SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . 223
Complex Interconnections Increase Neuron Versatility;… Fatigue;…
Overview Of Your Nervous System;… When Little Is Known, We Much
Prefer To Express It In Latin;… Your Autonomic (Self-Governing) Nervous
System;… Cerebrospinal Fluid And Meninges;… Your Blood Brain
Barrier;… Memories Are Made Of This?… A Few Hints;… Just Think
About It;… All Creatures Provide Evidence;… You Think, Therefore You
Are (So You Think)—A Very Brief Anatomical Review;… The Thalamus
And Hypothalamus (Under Thalamus).
CHAPTER 15: SPECIAL SENSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
Just What Is Going On?… We Are All In The Soup Together;… How You
Taste;… How You Smell;… What You Smell;… We Seek Pleasure;… Tastes
Vary;… Some Inputs Are More Important Than Others;… It Has Always
Been Harder To Listen Than To Talk;… Your Hearing Machine;… Inner
Ear;… Balance;… Hearing;… Cells Surrounded By High-Potassium
Solutions Must Accumulate Sodium Ions.
CHAPTER 16: IN YOUR EYE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273

Vision Dominates Your Internal Display of Reality;… Two Eyes Can See
Faster Than One;… A Pinhole Camera Makes Sharp Images;… Pinhole
Dynamics Depend Upon Slivers Of Bright Light;… Fingerhole Cameras
Require Lenses To Bring Incoming Light To A Focus;… Refraction Of
Incoming light;… Light Can Be Focused By Refraction;… Focusing On
Nearby Objects;… This Rainbow Is A Sign That A Flood Of Different
Frequencies Has Been Refracted;… Darwin Was Puzzled;… Following The
Light Path Through Your Eye;… Keeping An Eye Full;…
Accommodation;… Your Retina;… Right Brain Sees To The Left And Left
Brain Sees To The Right;… Your Retina Is Not Very Well Organized;…
Making A Spectacle For Yourself;… Fish Eyes;… The Retina In More
Detail.


xii

Human Evolutionary Biology

CHAPTER 17: YOUR ENDOCRINE SYSTEM SENDS SIGNALS . . . . . . 293
All Molecules Carry Information;… Life Cannot Avoid Signaling;… A
Signal Carries Information;… Signals Tend To Fade;… Circumstances Can
Alter Any Message;… One Small Step At A Time;… A Signal Molecule
Speaks To A Receptor Molecule;… By Its Response, The Receptor Amplifies
The Signal;.… Hormones Are Blood-Borne Signal Molecules With Specific
Targets;… Responses Must Be Timely And Appropriate;… Your DeathDeferring Design Is Exceedingly Complex;… Suicide Is Usually
Counterproductive;… Your Less Urgent Hormonal Signals Are Fat Soluble
And Act Via Intracellular Receptors;… More Urgent Signals Are WaterSoluble And Act At The Cell Surface;… Hormones Are Ordinary Signal
Molecules Sent Out By Your Endocrine Tissues Via Body Fluids;…
Cooperate Or Die;… Thalamus To Hypothalamus To Pituitary;… Your
Thyroid Regulates Your Metabolic Rate;… Your Parathyroids Stimulate

Your Osteoclasts;… Hormonal Control Of Blood Glucose;… Adrenal
Steroids Can Make You Strong And Sexy, Or Cause You To Retain Salt Or
Fall Apart;… Intermittent Release Improves Regulation.
CHAPTER 18: YOUR BLOOD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315
Life’s Waters;… You Really Are Quite Wet;… Blood Is Your Medium For
Exchange;… Your Just-In-Time Inventory System;… Moderation Pays;…
Blood Plasma Is Extracellular Fluid—Red Cells Contain Intracellular
Fluid;… Very Slowly, Blood Became Thicker Than Water;… Capillaries
Help Blood To Serve;… Your Red Blood Cells May Be Red But They Are
Not Cells;… Free Hemoglobin?… Your Inherited Blood Lines;… Your
Blood Is Made Specifically By And For You;… No Needles! (The “N”
Word);… Painless Experiment #1;… Painless Thought Experiment #2;…
Simple Painless Thought Experiment #3—Variations On “Blood Thinners”
(Anticoagulants) Played In Three Tubes;… Conclusion;… Normal Blood
Clotting Requires Platelets;… Cleaning Up Clots;… Red Cells And
Reticulocytes;… Painless And Neat Thought Experiment #4;… Sickle
Cells;… Blood Types And Transfusions.
CHAPTER 19: YOUR CARDIOVASCULAR SYSTEM . . . . . . . . . . . . . . . . 345
Your Blood—Move It or Lose It;… A Single Main Pulmonary Artery—A
Single Aorta;… Your Beating Heart Drives The Circulation That Powers
Your Beating Heart;… All About Bubbles;… It Can Make Your Blood
Boil;… Collateral Blood Flow;… Arteriosclerosis, Atherosclerosis,


Table of Contents

xiii

Aneurysm;… An Embolus Can Only Go So Far;… All Muscles Pump Iron
To Help Sustain Themselves;… Encourage One-Way Blood Flow To

Improve Circulatory Efficiency;… Murder?… Your Dynamic Veins;…
Heart Muscle;… Heart Muscle Cells Squeeze Incompressible Blood—Heart
Valves Maintain One-Way Flow;… Things Really Were Different Before
You Were Born;… Your Coming Out Led To Big Changes;… Your
Inevitable Heart;… Capillaries And Lymphatics;… Heat, Rest, Elevation,
Antibiotics;… Sometimes You Cannot Get There From Here;… X-Ray
Shadows;… Measuring Blood Pressure;… Pressures And Flows;… Your
Parts Tend To Fit.
CHAPTER 20: IMMUNITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
Know Thine Enemy;… Be Strong;… To Thine Own Self Be True;…
Prevention, Localization And Delay;… The Battle Plan: Your Shock
Troops;… The Follow-Up: Choosing The Perfect Weapon;… Command
And Control;… Preparing For The Next Attack;… Us Against Them;…
Monoclonal Tools.
CHAPTER 21: RESPIRATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403
Life Is One Big Gas Exchange;… Partial Pressures And All That;… CO2
Tension And CO2 Content May Differ Markedly;… Gills And Lungs:
Everted And Inverted Gas Exchangers;… Pumping Air;… Conserving
Water;… Conserving CO2;… Lung Should Be Elastic.
CHAPTER 22: DIGESTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427
Overview;… Laundering Your Stolen Assets;… How You Eat;… How You
Swallow;… It Ain’t Necessarily So;… Dissolving Your Prey;… Dissolving
Your Bacterial Competitors;… Osmosis Again;… Hormones And
Enzymes;… Exposing Your Villi;… Fighting Over Your Lunch;… Another
Noble Plumber Who Risked Plumbism;… Too Good To Waste?… Exploring
The Human Abdomen;… The H Word;… Ostomies;… Soil Is Alive—It
May Be Healthy Or Sick.
CHAPTER 23: METABOLISM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453
Life’s Shared Complexity;… Life Is Sweetness And Light;… Oxidation And
Reduction—Electron Grabber Seeks Electron Donor;… Your Sweet Power

Requires Free Oxygen As An Electron Acceptor;… Your Slow Burn;… Joan
Of Arc Preferred Men’s Clothes;… Glycolysis;… Kreb’s Cycle;… Oxidative
Phosphorylation—The Payoff Comes In Transferring Electrons To O2


xiv

Human Evolutionary Biology

CHAPTER 24: YOUR KIDNEYS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 471
The Value In Urine;… Countercurrent Extraction;… Cells Like It
Boring;… How Blood Filtrate Becomes Urine;… How You Urinate;…
Filtering Your Blood;… Salvaging That Filtrate;… ADH And All That;…
Renal (Kidney) Failure.
CHAPTER 25: WATER AND SALT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485
Your Inner Seas—A Quick Review;… Your Dynamic Fluid Balance;…
Fluid Losses May Be External Or Internal, Permanent or Temporary;…
Blood Loss And Fluid Replacement.
CHAPTER 26: DOING WHAT COMES NATURALLY . . . . . . . . . . . . . . . 497
Frequent Spousal Sex Strengthens Human Families As Well As Causing
Pregnancies;… It Took A Lot Of Preparation;… The Egg Came First;…
How It Works;… Your Inside-Out Connections;… Avoiding Pregnancy And
Avoiding Venereal Infections;… Menopause;… Testes Hang Out to be
Cool;… Sperm Are Not Very Smart;… Delivering Your Sperm;… Mitosis
and Meiosis—Diploid And Haploid.
CHAPTER 27: GROWTH AND DEVELOPMENT . . . . . . . . . . . . . . . . . . 521
You Used To Be A Good Egg;… The Egg That Would Be You;… Changing
Patterns—How Living Matter And Energy Interact In The Fourth
Dimension (Time);… Your Coming Out;… No Strings.
INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 539

PREFACE

E

veryone is interested in human biology. Human anatomy and physiology
permeate our everyday experiences from earliest childhood onward. Biology
holds the key to our health and sickness, love and hate, reproduction and digestion, adolescent rebellion and death. Indeed, the study of human biology unlocks
the door to an understanding of life itself.
Students enroll in Human Anatomy and Physiology to learn more about themselves. Too often they find the pathway toward useful knowledge blocked by endless
lists of human anatomical parts bearing unpronounceable Latin names that must
be memorized. Not surprisingly, many beginning biology students soon become
discouraged and drop out. For those who persist just long enough to complete
some minimal science requirement, recurrent nightmares about the final examination may be their most lasting memory. Yet little that is final will be found in any
final examination, especially in biology where researchers are doubling the information content every five to seven years. Thus, beginning science courses are
generally more helpful when they emphasize the “Big Picture” rather than requiring reliable regurgitation of arbitrarily selected details from some soon-to-be-revised
illustrated catalog of facts. Furthermore, too many facts can easily confuse the student and thereby obscure both the beauty and incredibly rich organization of life.
Earth without life is difficult to imagine. Yet life itself is so strange that you
never could imagine it, were it not already so familiar. When introducing strangers,
one customarily includes information on what they do (function) and where they
are from (ancestry). Our confidence increases when the stories of strangers contain
no unseemly gaps, obvious discrepancies or troublesome disclosures. Thanks to
many recent discoveries, we finally can introduce some of the stranger ancestral
contributions to your own anatomy and physiology without encountering overwhelming gaps or obvious discrepancies—whether this human story contains
troublesome disclosures is for you to decide.

xv

xvi

Human Evolutionary Biology

Those with no background in science may find the first few chapters quite
difficult. Nonetheless, a moderate effort invested here will reveal how physical and
chemical processes set in motion by the Big Bang both constrained and enabled
life’s origin and progression. However, if physics and chemistry are inaccessible to
you, do not despair. Just give it your best shot and keep moving, for later chapters
can still be enjoyed without that preparation. But then you may have to take my
word for how some things came about, rather than evaluating evidence of life’s
amazing advances for yourself. On the pages that follow, topics are developed in
ordinary English, accepting the risk of appearing simplistic or even crude in the
pursuit of clarity. Specialized terminology is brought in sparingly as needed, so that
it becomes a useful tool or helpful mooring rather than an impediment. Each chapter
is designed to correct and expand upon knowledge that you already possess about
yourself and the world, without wasting your time. While individual chapters can
stand alone, needless repetition has been avoided. Therefore you will find this material most digestible when taken in the order that it is served.


PROLOGUE TO CREATION
Overview;… All creatures bear evidence;… What is scientific evidence,
and how can we be sure?… There are thousands of religions but just one
science;… There is no scientific basis for any religion;… Religions lose
credibility when they attack science;… How shall we recognize scientific
truth when we see it?… A never-ending series of questions leads to new
scientific discoveries;… Correlation, causation, anecdotal evidence and
biased reporting;… So you must decide.

Overview

Nature is prolific. Resources are limited. Competition is fierce. Variation is
inevitable. Only the most fit survive to reproduce. Thus natural selection brings
about endless adaptive changes.

All Creatures Bear Evidence
Human anatomy and physiology are incredibly complex. Much is unknown—
no one really understands the rest. And important advances in human biology are
as likely to come from careful studies of yeast, bacteria, worms, fruit flies, corn,
squid, toads or mice as from any direct examination of human function and malfunction. Indeed, such investigations regularly reconfirm how inextricably humans
are entangled with the natural world from which they derive—which suggests that
we really cannot know what we are without knowing how we got that way. But
only in the past 150 years has the serious consideration of human origins finally
moved from philosophical discussions on the Nature of Man and unforgiving religious disputes about Creation myths to a meticulous investigation of the copious
evidence that surrounds us all. Tremendous advances in scientific instrumentation
and understanding now uncover life’s secrets at an ever-accelerating pace. Some of
these findings have obvious immediate impacts, others more stealthily upset the
way that we view ourselves. But old ideas rarely give way without protest. While
much of this new and revolutionary information has yet to enter public awareness,
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already there is much dispute. So why are things moving so fast? And why all the
dispute? Ought we not slow things down a bit until we can figure out what really is
going on and what it all means? Well, fortunately or unfortunately, there is no
stopping or going back. Returning to the good old days of continuous conflict over
limited resources is impossible—furthermore it is pointless, since modern problems only respond to the most up-to-date and productive solutions.

Science is a cumulative adventure with each advance providing grounds for
future research. No matter how inconvenient any new bit of information may be
or how poorly it happens to fit the prevalent world view, such evidence can neither
be ignored nor forgotten. Thus science brings a directionality to world history that
is independent of all but the most catastrophic external changes. Nonetheless, the
unexpected arrival of scientific discoveries without instructions for their use has
always posed problems—for the public’s understanding of science inevitably lags
far behind the reality and even competent science teachers may lose their grip as
copious new information displaces some of the old and alters the rest beyond recognition. Under such circumstances, the perplexed often seek reassurance and
guidance from more traditional non-scientific authorities. These include many fundamentalist Christian leaders who are now trying to stem the rising tide of knowledge
that threatens to wash away their own doctrine/following/life-style. Individuals
most heavily invested in the status quo undoubtedly preached similar versions of
hell-fire and damnation when our ancestors first learned to make fire, build a boat
or plant a crop. But the ongoing information explosion can no longer be contained
by any power on Earth. Nor can our human population explosion long continue
without endangering all life on Earth.
Quite clearly, change is inevitable. Science merely accelerates that change and
directs it into many new dimensions occupied by scientific concepts such as domesticated crops and animals, radios and televisions, automobiles and antibiotics,
blood transfusions and birth control pills, computers and nuclear power, vitamins
and pesticides. By creating winners and losers, change always generates dispute. Yet
it takes religious involvement to make most disputes intractable—for religious fervor and finances flourish through the denial of any common factual basis for conflict
resolution. The very human tendency toward outrage and passion—the “us against
them” mind-set so easily stirred and inflamed by political and religious demagogues,
has long brought power and profit to crusaders, invaders and more ordinary lynch
mobs. But even though times have changed and peace now promotes productivity
beyond the wildest dreams of our club-wielding ancestors, still we remain locked in
costly and counterproductive struggles about tribal and territorial matters, human
sexuality and population control, genetic studies and abortion, primarily because

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one or both sides remain sufficiently inflamed by religious (and other divisive)
rhetoric to disregard obvious common interests. Fortunately, much new and revolutionary information about human biology is beginning to clarify many of the
biological misconceptions and misdirected biological drives upon which such disputes are based. But even if (and as) additional facts become available that can help
to settle these difficult matters objectively, how will you know whether information being provided is reliable? Well, before you accept statements made in this
book or elsewhere, you should ask “Says who?” and “What is the evidence?”. Let us
therefore begin this brief discussion on the nature of scientific evidence by clarifying certain vital but widely misunderstood differences between science and religion.

There Are Thousands of Religions But Just One Science
A religion tells a story, detects a direction, reveals a plan, requires appropriate
behavior in response to external authority, promises an outcome and offers certainty in an uncertain world. Because religions wrestle with eternal truths, they
find it extraordinarily difficult to change with the times. Yet times always change,
so in order to persist, any religion must evolve and adapt, often to the point where
its original premises appear irrelevant and its previous manifestations would constitute outrageous or criminal conduct (e.g. human sacrifice, or stoning to death as
punishment for adultery or for being disrespectful to one’s parents). A study of
history suggests that even the most powerful and bloodthirsty religious authorities
cannot dominate everyone for long. So new and offshoot religions are as unavoidable as the ceaseless enmity within and between quite similar religions that still
causes such endless grief and suffering.
Scientific inquiries seek order in the apparent randomness of nature while
religious answers attempt to impose order. Scientists study what is. Religious authorities define what ought to be. But the fact that many people share an idea does
not make that idea a fact. For a fact refers to something that actually exists, a valuefree part of reality, a demonstrable truth. On the other hand, ideas, thoughts and
concepts often deal with values. An idea may be helpful or interesting, noble and
uplifting, merely crass or even despicable. But in the end, all ideas represent attempts at problem solving, efforts to organize facts in a more meaningful fashion.
Of course, facts only have relevance when ideas organize them into coherent entities that can be manipulated for fun, profit and reproductive advantage. Yet all
ideas remain mere approximations, subject to later modifications. And every idea
must compete with contrary ideas until new evidence accumulates that further
refines our understanding of ourselves and the Universe. Scientific progress means

change. Although organized religions and science may overlap in their subject matter


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to some degree, they represent such entirely different approaches to life that they
have nothing in common. This implies that neither is better than the other—they
simply cannot be compared.

There Is No Scientific Basis For Any Religion
In their search for consistency and authority, newly organized religions commonly include current scientific thinking in their lore. As a result, many out-of-date
scientific concepts remain embedded within the belief systems of long-established
religions. There they are passed over as quaint anachronisms by later generations of
believers. Yet even the most scientifically up-to-date religious answers, insights or
predictions cannot contribute to scientific progress, for religious explanations are
so all-encompassing that they can neither be verified nor falsified. Furthermore,
the arbitrary distribution of life’s rewards and punishments puzzles even the most
religious, yet that is what religions presume to explain. Many of the devout therefore find a perverse confirmation of God’s greatness in His apparent lack of respect
for ordinary human concerns. Even if they cannot understand Him or affect His
behavior, at least they can be on His team. But for others, the interposition of a
random God between suffering humanity and a random Universe merely displaces
the difficulty of understanding without resolving anything.
Some scientists view any claims of close communication with God as ordinary consumer fraud. Yet one could hardly expect a faithful following to invest
hard-earned assets without some hint at inside information—unless an aspiring
man-of-the-cloth chose to occupy the moral high ground with its great visibility
and notoriously slippery slopes. Other scientists maintain strong personal religious
beliefs by keeping science and religion “in separate parts of their brain”. But regardless of how many prominent scientists may worship within any major or minor
religion, their own religious beliefs can no more verify that particular religion than

they falsify any confirmed scientific evidence. In addition, even famous scientists
often lack an open mind and adhere religiously to some scientific hypothesis (testable prediction) as dogma (established opinion—not to be challenged) long after it
has been discredited by new evidence. Thus outmoded scientific ideas may persist
through various reincarnations until the affected generation of scientists has passed
on. Meanwhile, the unstoppable avalanche of new information tends to leave busy
scientists just as poorly informed as other educated laypersons on matters outside
of their immediate area of expertise (in which they often learn more and more
about less and less).
Nonetheless, uncertainty is uncomfortable and indecision can be unsafe so


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intelligent creatures feel a strong urge to study, organize and explain. Therefore
religious and non-religious thinkers alike tend to accept the most plausible explanation once they have eliminated other alternatives that come readily to mind. But
scientific ideas must forever be retested against any legitimate evidence. So while
life endures and facts still accumulate, science will continue to evolve. In contrast,
religions usually require (“or else!”) acceptance of internal or authoritatively communicated evidence that is not equally accessible to all. For religiously acceptable
evidence such as a vision cannot be evaluated/reviewed/measured by other competent objective observers. In other words, religious evidence usually is subjective and
thus not falsifiable. Religious rewards also must be taken on faith, as they generally
are collected in the hereafter rather than being distributed in the here-and-now
where all can observe.

Religions Lose Credibility When They Attack Science
Controversies between religions are essential and unending. Religions differ
and those differences must seem significant if a religion is to prosper. Indeed, the
many religious regulations and disputes that isolate true believers also help them to
keep the faith while attracting new adherents. Most religions recognize only one set

of beliefs (fortunately their own) as true. Although religions regularly reinterpret
scientific evidence to suit their own requirements, established religions gradually
learn not to attack science directly. For no religion can retain long-term credibility
if it is based upon obviously untrue claims about the world in which we all live—
eventually every religion must come to grips with established reality. But major
revelations do not come easily to conservative organizations—which explains the
current Christian fundamentalist demand that U.S. public school students be taught
how God created the Universe just a few thousand years ago. While such a quaint
belief may have seemed plausible several hundred years ago, it clearly is refuted by
every modern measurement. Nonetheless, the biblically based contention that Earth
was created just over 5750 years ago is aggressively promoted as creation science.
But creationism has no more to do with science than does Scientology or any other
so-called Religious Science. Although it can be useful to group mutually incompatible terms in this fashion for their shock value or confusional impact, or to adopt
respected terms such as science and research in order to share their hard-earned aura
of truth and objectivity, such juxtapositions as “creation science” or “Christian
Science” are as obviously oxymoronic as “Hell’s Angels” or “Jews for Jesus”.
Interestingly, creationists continue to proclaim biblical infallibility despite
obvious inconsistencies (starting with the two incompatible versions of creation in


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Genesis) and ample scholarly evidence for multiple authorship of the Hebrew Bible
(Old Testament). Indeed, both Old and New Testaments have undergone repeated
revisions over the centuries (for example, compare the varied tales of Matthew,
Mark, Luke and John). Furthermore, while creationists rely heavily upon promises
of Heaven and Hell as carrot and stick, neither Heaven nor Hell are even mentioned in the entire Hebrew Bible. Yet that sacred text dates back to a time when
God supposedly roamed the Earth, helping His chosen few, smiting many others

and even causing an occasional pregnancy. In addition, many Bible stories are quite
obvious adaptations of older near-Eastern myths. But rather than utilize their Godgiven intelligence for questioning their own beliefs (which would be sinful and
possibly dangerous), these fundamentalists tend to devote their intellects to snappy
anecdotal proofs such as “I know God exists because I have a personal relationship
with Him”—or when other arguments ring hollow, to simply pleading “Why not
believe? What have you got to lose?” (other than the freedom to think and live as a
rational human being).

How Shall We Recognize Scientific Truth When We See It?
Overwhelming scientific evidence (accessible to any interested observer)
demonstrates that the entire Universe, including our Earth, is many billions of
years old. Yet some creationists still try to explain away starlight that has traveled
for billions of light years—or radiometric data and copious fossil evidence derived
from ancient rocks—or uninterrupted sequential yearly deposits displayed in ice
and sediment cores that date back several hundred thousand years—or even the
annual growth rings from very old live bristlecone pines that overlap datable growthrings of still older preserved pine logs to provide a continuous record of annual tree
rings covering the past 8000 years—by alleging that when God set the whole thing
in motion less than six thousand years ago, He also manipulated the evidence to
make the Universe merely seem ancient. Comparable, perhaps, to the way modern
manufacturers create antique furniture. But if some evidence provided by God is
admittedly bogus, how can one have confidence in His word on other matters?
In the early 14th century, an English cleric, William of Ockham, provided a
useful guideline for determining what is true. Ockham’s Razor or the parsimony
principle declares “That which can be done with less is done with more in vain”.
In other words, where a simple explanation will suffice, the more complex
explanation generally has little merit. When Ockham’s Razor is applied to the
question of how long ago Earth formed, it suggests that other explanations are far
less convincing than the simple idea that Earth really is as old as all scientific measurements would indicate. On the other hand, truly simple explanations that

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encompass all eventualities, such as “It was God’s will” or “God must have been
watching over me” or “God works in mysterious ways” are not scientifically useful
since they are incomplete. Having no predictive power, they cannot be tested. And
in the end, all answers that defer to God’s judgment or imply Heavenly compensation for torment suffered here on Earth must fall short, for “No promise of Heaven
1
can rectify Auschwitz”.
Still, one might reasonably argue that any of the thousands of major or minor
religions within and about which people continue to bleed and die has thereby
earned the right to be presented to students of religion. But surely there is no
justification, especially under the Constitution of the United States, for presenting
any specific religious belief such as creationism to students being educated in science at public expense. Creationism is no more the only reasonable alternative to
science than it is the only reasonable alternative to sourdough bread. Religion and
science are just not related.

A Never-ending Series Of Questions Leads To New Scientific Discoveries
This book presents biology as I understand it. When appropriate, I will refer
to confirmatory evidence. Obviously, I, and you in turn, must accept a lot of incomplete evidence and work reported by others on faith. But I have tried to make
only statements that seem consistent with scientific evidence and experiments currently being reported in reputable scientific journals. Those reports generally are
sufficiently detailed so that other scientists can reevaluate the data presented or
gather additional evidence to refute or confirm any of the conclusions advanced.
But science is more an endlessly self-correcting process than a result, so much of
the material presented in this book will eventually turn out to be approximate,
dated or even incorrect as new evidence is unearthed and new relationships are
discovered. After all, even advances worthy of the Nobel Prize soon become outmoded by new information. Nonetheless, that growing flood of new information
does not imply that scientific studies leading to the automobile or airplane or “H”
bomb—or to an approximate age for the Universe—have been discredited. Those

autos will keep chugging, the planes will stay aloft and the bombs may explode
regardless of any new and better theoretical understanding of thermodynamics.
Clear and convincing evidence similarly assures us that Earth will remain billions
of years old no matter how our ability to date her rocks, wrinkles and fossils may
improve in their accuracy. In other words, uncertainty about tomorrow’s weather
does not make all eventualities equally probable—rain forests continue to generate
and receive rain—deserts are likely to remain dry.
Disagreements between competent and often highly competitive scientists
1

As quoted by J. Polkinghorne in Science and Providence SPCK Holy Trinity Church, London, 1989.