Animal Diversity

457 Pages·2003·5.44 MB·English

by  Cleveland P Hickman

Authors: Cleveland P. Hickman, Jr., Larry S. Roberts, Allan Larson
Edition: 3rd
ISBN: 0-07-234903-4
Description: ©2003 / Softcover / 464 pages
Publication Date: June 2002
Overview
The third edition of Animal Diversity presents a survey of the animal kingdom with emphasis on
diversity, evolutionary relationships, functional adaptations, and environmental interactions. It is
tailored for a one-semester or one-quarter course and is appropriate for both non-science and
science majors.
Features
• Covers the "heart" of a zoology course: a complete discussion of animals (protozoa to mammals). These chapters
are preceded by an introduction to classification, evolution and animal architecture.
• Length: Half the size of standard Zoology texts. Level: Appropriate for intermediate level courses needing an
abbreviated version of the longer Hickman titles.
• Classification: Taxonomy is presented with both the Linnaean system and with cladistics via cladograms. Students
and professors both benefit by having both systems presented in the text. Students are better prepared by studying both.
The material on cladistics can be easily skipped if so desired by the instructor.
• This text contains modern, thoroughly researched coverage of the phyla of animals. It emphasizes the unifying
architectural and functional themes of each group.
• Descriptions of appropriate web links appear at the end of every chapter.
• VALUE- the most concise and least expensive book in the market.
New to This Edition
• Chapter 2 covering ecology is new to this third edition. It explains the principles of
ecology, with emphasis on populations, community ecology, and variations in life history
strategies of natural populations. The treatment includes discussions of niche, population
growth and its regulation, limits to growth, competition, energy flow, and nutrient cycles.
• The sixteen survey chapters of animal diversity that form the central theme of this book
are prefaced by four chapters with discussions of the principles of evolution, ecology,
classification, and animal architecture. Throughout this revision references have been
updated and the writing style has been simplified and streamlined.
• Chapter 5 on protozoan groups was completely revised for this edition. Molecular
sequencing of bases in genes has revealed that the former phylum Protozoa embraces
numerous phyla of varying evolutionary relationships. These groups of animal-like
unicellular eukaryotes are grouped in this chapter as a convenience without implying that
they form a monophyletic group.
• Chapter 8 (acoelomate animals) features a rewritten section on turbellarians to emphasize
their paraphyly, yet retaining the class Turbellaria to avoid the objectionable taxonomic
complexity that strict cladistic analysis would require.
• While still covering all pseudocoelomates in a single Chapter 9, the authors now group
the various phyla in superphyla Lophotrochozoa (Rotifera, Acanthocephala, Gastrotrica,
and Entoprocta) and Ecdysozoa (Nematoda, Nematomorpha, Kinorhyncha, and
Priapulida).
• In the phylogeny section of chapter 12 (arthropods) we revisited the Lophotrochozoa-
Ecdysozoa question, as well as the possibility of polyphyly of Arthropoda, and the new
hypothesis that myriapods are a sister group to all other arthropods and that insects and
crustaceans form a monophyletic group.
• Chapter 13 (lesser protostomes) was reorganized to group lophotrochozoans (Sipuncula,
Echiura, Pogonophora, Brachiopoda, Ectoprocta and Phoronida) and ecdysozoans
(Pentastomida, Onychophora, Tardigrada, and Chaetognatha) together. Chaetognatha
were transferred to this chapter on the strength of evidence that they are protostomes,
despite their morphological similarities with deuterostomes. Molecular evidence strongly
supports placement of lophophorate phyla in Protosomia, and division of their coelom
similar to deuterostomes must be convergent.
• In chapter 15 (vertebrate beginnings) the authors revised and shortened discussions of
pharyngeal filter-feeding, ancestry and evolution of chordates, and Garstang's hypothesis
of larval evolution.
• The many changes in chapter 16 (fishes) include a revision of origin and evolution of
fishes, and fish classification. In current classifications the traditional term Osteichthyes
as applied to all bony fishes does not describe a monophyletic grouping; rather the two
major lineages of bony fishes are now divided into two classes containing ray-finned
fishes (Actinopterygii) and lobe-finned fishes (Sarcopterygii).
• In chapter 19 (birds, the section covering evolution has been revised to explain the
recently adopted division of living birds into paleognathous and neognathous groups,
replacing the older terminology of ratite and carinate to describe flightless and flying
birds respectively.
• Among the many changes in chapter 20 (mammals) are revisions of the sections on horns
and antlers, glands, food and feeding, primate classification, and human evolution.
Hickman−Roberts−Larson: Front Matter Preface © The McGraw−Hill
Animal Diversity, Third Companies, 2002
Edition
• • • • • •
p r e f a c e
Animal Diversity is a textbook tailored for the restrictive ples of Zoology, in which it was completely revised and
requirements of a one-semester or one-quarter course and is updated.It explains the principles of ecology,with emphasis
appropriate for both non-science and science majors of vary- on populations,community ecology,and variations in life his-
ing backgrounds.This third edition of Animal Diversity pre- tory strategies of natural populations.The treatment includes
sents a survey of the animal kingdom with emphasis on discussions of niche,population growth and its regulation,lim-
diversity, evolutionary relationships, functional adaptations, its to growth,competition,energy flow,and nutrient cycles.
environmental interactions,and certainly not least,readability. Chapter 3 on animal architecture is a short but important
We also continue with several pedagogical aids for students: chapter that defines the organization and development of
opening chapter dialogues that relate a theme or topic drawn body plans distinguishing major groups of animals.This chap-
from the chapter;chapter summaries and review questions to ter includes a picture essay of tissue types and a section
aid student comprehension and study;accurate and visually explaining important developmental features associated with
appealing illustrations; in-text derivation of generic names; the evolutionary diversification of the bilateral metazoa.
chapter notes and short essays that enhance the text by offer- Chapter 4 treats classification and phylogeny of animals.
ing interesting sidelights to the narrative; pronunciation of We present a brief history of how animal diversity has been
taxa in the tables of classification;and an extensive glossary organized for systematic study,emphasizing current use of Dar-
providing pronunciation, derivation, and definition of terms win’s theory of common descent as the major principle under-
used in the text. lying animal taxonomy.Continuing controversies between the
schools of evolutionary taxonomy and phylogenetic systematics
(cladistics) are presented,including a discussion of how these
Organization and Coverage
alternative taxonomic philosophies affect our study of evolu-
tion.Chapter 4 also emphasizes that current issues in ecology,
The sixteen survey chapters of animal diversity that form the
evolution,and conservation biology all depend upon our taxo-
central theme of this book are prefaced by four chapters with
nomic system.For this edition we added a new boxed essay
discussions of the principles of evolution,ecology,classifica-
illustrating use of molecular phylogenetic procedures, and
tion, and animal architecture. Throughout this revision we
updated higher-level phylogeny and taxonomy of the bilateria.
updated references and worked to simplify and streamline the
The sixteen survey chapters are a comprehensive,mod-
writing style.
ern,and thoroughly researched coverage of the animal phyla.
Chapter 1 begins with a brief explanation of the scientific
We emphasize the unifying architectural and functional theme
method—what science is (and what it is not)—and then moves
of each group.Structure and function of representative forms
to a discussion of evolutionary principles.Following an histori-
are described,together with their ecological,behavioral,and
cal account of Charles Darwin’s life and discoveries,the five
evolutionary relationships.Each chapter begins with succinct
major components of Darwin’s evolutionary theory are pre-
statements of “Position in the Animal Kingdom”and “Biologi-
sented,together with important challenges and revisions to his
cal Contributions.”Students have found these opening state-
theory and an assessment of its current scientific status.This
ments, a distinctive feature of this text, to be important in
approach reflects our understanding that Darwinism is not a sin-
assisting their approach to each chapter.
gle,simple statement that is easily confirmed or refuted.It also
The classifications in each chapter are positioned follow-
prepares the student to dismiss the arguments of creationists
ing other coverage of a particular group,in most cases imme-
who misconstrue scientific challenges to Darwinism as contra-
diately preceding the summary at the end of the chapter.
dictions to the validity of organic evolution.The chapter ends
Discussions of phylogenetic relationships are written from a
with discussion of micro- and macroevolution.The essay on the
cladistic viewpoint, and cladograms have been presented
animal-rights controversy is also updated.
where possible.These show the inferred branching events in
Chapter 2 on ecology is new to this third edition,derived
each group’s history and the origin of some of the principal
from the 11th edition of its larger sibling,Integrated Princi-
shared derived characters.Traditional phylogenetic trees have
xiii
Hickman−Roberts−Larson: Front Matter Preface © The McGraw−Hill
Animal Diversity, Third Companies, 2002
Edition
xiv preface
been drawn to agree with cladistic analyses as closely as possi- Teaching and Learning Aids
ble.Because cladistics is not embraced by all teachers,we have
presented cladograms as supplemental to the conventional
Linnaean classifications. Vocabulary Development
Some of the principal changes in these survey chapters
Key words are boldfaced and derivations of generic names of
follow.Chapter 5 on protozoan groups was completely revised
animals are given where they first appear in the text.In addi-
for this edition.Molecular sequencing of bases in genes has
tion,derivations of many technical and zoological terms are
revealed that the former phylum Protozoa embraces numerous
provided in the text;in this way students gradually become
phyla of varying evolutionary relationships.These groups of
familiarized with the more common roots that recur in many
animal-like unicellular eukaryotes are grouped in this chapter
technical terms.An extensive glossary provides pronunciation,
as a convenience without implying that they form a mono-
derivation,and definition of each term.
phyletic group.In chapter 8 (acoelomate animals) we rewrote
the section on turbellarians to emphasize their paraphyly,yet
retaining the class Turbellaria because the taxonomic com- Chapter Prologues
plexity of a strictly cladistic classification is beyond the scope
of an introductory textbook. A distinctive feature of this text is an opening essay placed in a
While still covering all pseudocoelomates in a single panel at the beginning of each chapter.Each essay presents a
chapter (chapter 9),we now group the various phyla in super- theme or topic relating to the subject of the chapter.Some pre-
phyla Lophotrochozoa (Rotifera,Acanthocephala,Gastrotricha, sent biological,particularly evolutionary,principles;others illu-
and Entoprocta) and Ecdysozoa (Nematoda,Nematomorpha, minate distinguishing characteristics of the group treated in
Kinorhyncha, and Priapulida). In the phylogeny section of the chapter.Each is intended to present an important concept
chapter 12 (arthropods), we revisited the Lophotrochozoa- drawn from the chapter in an interesting manner that will
Ecdysozoa question,as well as the possibility of polyphyly of facilitate learning by students,as well as engage their interest
Arthropoda.We discuss the new hypothesis that myriapods and pique their curiosity.
are a sister group to all other arthropods and that insects and
crustaceans form a monophyletic group.Chapter 13 (lesser
Chapter Notes
protostomes) was reorganized to group lophotrochozoans
(Sipuncula, Echiura, Pogonophora, Brachiopoda, Ectoprocta
Chapter notes,which appear throughout the book,augment
and Phoronida) and ecdysozoans (Pentastomida, Onycho-
the text material and offer interesting sidelights without inter-
phora,Tardigrada,and Chaetognatha) together.Chaetognatha
rupting the narrative.
were transferred to this chapter on the strength of evidence
that they are protostomes,despite their morphological simi-
larities with deuterostomes.Molecular evidence strongly sup- For Review
ports placement of lophophorate phyla in Protosomia, and
Each chapter ends with a concise summary,a list of review
the division of their coelom similar to deuterostomes must be
questions,and annotated selected references.The review ques-
convergent.
tions enable students to test themselves for retention and
In chapter 15 (vertebrate beginnings) we revised and
understanding of the more important chapter material.
shortened discussions of pharyngeal filter-feeding, ancestry
and evolution of chordates,and Garstang’s hypothesis of larval
evolution.The many changes in chapter 16 (fishes) include Art Program
revision of origin and evolution of fishes,and fish classifica-
tion. In current classifications the traditional term Oste- The appearance and usefulness of this text are much
ichthyes as applied to all bony fishes does not describe a enhanced by numerous full color paintings by William C.Ober
monophyletic grouping;rather the two major lineages of bony and Claire W.Garrison.Bill’s artistic skills,knowledge of biol-
fishes are now divided into two classes containing ray-finned ogy,and experience gained from an earlier career as a practic-
fishes (Actinopterygii) and lobe-finned fishes (Sarcopterygii). ing physician,have enriched the authors’other zoology texts
In chapter 19 (birds) we revised the section on origin and rela- through several editions.Claire practiced pediatric and obstet-
tionships to explain the recently adopted division of living ric nursing before turning to scientific illustration as a full-time
birds into paleognathous and neognathous groups,replacing career. Texts illustrated by Bill and Claire have received
the older terminology of ratite and carinate to describe flight- national recognition and won awards from the Association of
less and flying birds,respectively.Among the many changes in Medical Illustrators, American Institute of Graphic Arts,
chapter 20 (mammals) were revisions of the sections on horns Chicago Book Clinic,Printing Industries of America,and Book-
and antlers,glands,food and feeding,primate classification,and builders West. Bill and Claire also are recipients of the Art
human evolution. Directors Award.
Hickman−Roberts−Larson: Front Matter Preface © The McGraw−Hill
Animal Diversity, Third Companies, 2002
Edition
Preface xv
Web Pages Student Study Guide
At the end of each survey chapter is a selection of related The General Zoology Student Study Guide by Jane Aloi and
internet links dealing with the chapter’s topics.The URLs for Gina Erickson is a useful tool for student review and study.It
the pages are found in the text’s Online Learning Center at provides self-testing,valuable study tips,and chapter summary
www.mhhe.com/zoology(click on this book’s cover). activities,including critical thinking exercises.
Supplements Animal Diversity Online Learning Center
The Internet provides a new route for learning and studying.
Instructor’s Manual McGraw-Hill has designed a website to support the Zoology
field of study.This Online Learning Center provides live links to
The Instructor’s Manual provides a chapter outline, com-
related Internet sites that are described in Animal Diversity’s
mentary and lesson plan,and a listing of resource references
end-of-chapter pedagogy. In addition, you will find on-line
for each chapter.We trust that this material will be particu-
quizzing,information about careers in Zoology,key terms flash
larly helpful for first-time users of the text,although experi-
cards,a cladistics laboratory,Zoology Essential Study Partner,and
enced teachers also may find much of value.The Instructor’s
much more.You can find this site at www.mhhe.com/zoology.
Manual is available on this text’s Online Learning Center at
Just click on the cover of Animal Diversity.
www.mhhe.com/zoology(click on this book’s cover).
Digital Zoology
Computerized Test Bank
Digital Zoology Interactive CD-ROM by Jon Houseman is
Test questions are available as a computerized test generation
an interactive guide to the specimens and materials covered
system for IBM-compatible and Macintosh computers.Using
in zoology laboratory and lecture sessions.Laboratory mod-
this Brownstone Testing System,instructors can create tests
ules contain illustrations, photographs, annotations of the
and quizzes quickly and easily.Instructors can sort questions
major structures of organisms,interactive quizzes,and video
by type or level of difficulty,and can add their own questions
clips.Interactive cladograms within lab modules provide links
to the bank of questions provided.
to interactive synapomorphies of the various animal groups.
Key terms throughout the program link to an interactive glos-
Animal Diversity Laboratory Manual sary.This CD-ROM is the perfect student study tool to pro-
mote learning both in and outside of the zoology laboratory,
The laboratory manual by Cleveland P.Hickman Jr.and Lee B.
and also comes with an accompanying student workbook and
Kats, Laboratory Studies in Animal Diversity, is designed
website to provide additional study tips,exercises,and phyla
specifically for a survey course in zoology.
characteristics.
Transparency Acetates
Acknowledgments
A set of full-color transparency acetates of important textual
illustrations is available for instructors with this edition of Ani- We wish to thank the following zoologists for reviewing the
mal Diversity.Labeling is clear,dark,and bold for easy reading. second edition of this text:
Nancy M.Butler,Gustavus Adolphus College
Animal Diversity Slides
Kari L.Lavalli,Southwest Texas State University
Heinz Meng,State University of New York,New Paltz
A set of animal diversity slides,photographed by the authors
Michelle J.Solensky,University of Minnesota
(CPH and LSR) and Bill Ober on their various excursions,are
offered to instructors in this unique textbook supplement.Both
The authors express their gratitude to the able and conscien-
invertebrates and vertebrates are represented. Descriptions,
tious staff of McGraw-Hill who brought this book to its present
including specific names of each animal and brief overview of
form. We extend special thanks to Publisher Marge Kemp,
the animal’s ecology and/or behavior,accompany the slides.
Senior Development Editor Donna Nemmers,and Senior Proj-
ect Manager Susan Brusch.All played essential roles in shaping
Life Science Animations this third edition.
Difficult concepts like DNA replication,oxidation,and respira-
Cleveland P.Hickman,Jr.
tion can be learned through animation in this two CD-ROM
Larry S.Roberts
set.This instructor tool provides 300 animations to present
Allan Larson
complex life science processes in a method that fosters easier
learning and review.
Hickman−Roberts−Larson: Front Matter Preface © The McGraw−Hill
Animal Diversity, Third Companies, 2002
Edition
T h e
O n l i n e L e a r n i n g C e n t e r
y o u r
p a s s w o r d
t o s u c c e s s
This text–specific website allows students and instructors animations,a cladistics laboratory,a zoology timeline,and more.
from all over the world to communicate.Instructors can create Also available here is the Zoology Essential Study Partner—an
a more interactive course with the integration of this site,and engaging,investigative tutorial to reinforce what you are learning
students will find tools such as practice quizzing,key term in your zoology course.This Zoology Essential Study Partner
flashcards,and animations that will help them improve their contains interactive diagrams,animations,quizzing and testing
grades and learn that zoology can be fun.Use the passcode for each unit,and many other valuable features.
card within this textbook to access the many learning tools
that accompany the chapters in this book.
Teaching Tools for Instructors
Learning Tools for Students The Instructor’s Resources section of the Animal Diversity
Online Learning Center hosts the Instructor’s Manual,which
For every survey chapter in the Animal Diversity, 3rd edition provides a chapter outline,commentary and lesson plan,and
textbook,a variety of useful study tools are available on the Ani- listing of audiovisual resource references for each chapter.
mal Diversity Online Learning Center. Within the Student Also available to instructors is an Animal Diversity Power-
Resources section of this OLC,students will discover chapter- Point,containing 200 slides and species/origin information,to
sorted links to web pages of related content for further reading enhance classroom presentation.Instructors will also find a
and research.All key terms from each chapter are available as list of slides and transparencies available to them for class-
flashcards on this website,in addition to chapter-sorted quizzing, room presentation.
xvi
Hickman−Roberts−Larson: 1. Science of Zoology and Text © The McGraw−Hill
Animal Diversity, Third Evolution of Animal Companies, 2002
Edition Diversity
1
Mamos
liwi
c h a p t e r • • • • • •
o n e
Science of Zoology and Evolution
of Animal Diversity
A Legacy of Change
The major feature of life’s history is a legacy of perpetual change.
Despite an apparent permanence of the natural world,change charac-
Kauai terizes all things on earth and in the universe.Countless kinds of ani-
akialoa mals and plants have flourished and disappeared,leaving behind an
imperfect fossil record of their existence.Many,but not all,have left
Laysan finch Kona finch living descendants that bear a partial resemblance to them.
Akepa Maui parrotbill Life’s changes are perceived and measured in many ways.On a
Nukupuu
short evolutionary timescale,we see changes in the frequencies of
different genetic variants within populations.Evolutionary changes in
Alauwahio Anianiau relative frequencies of light- and dark-colored moths were observed
within a single human lifetime in the polluted areas of industrial Eng-
Palila land.Formation of new species and dramatic changes in appearances
Amakihi of organisms,as illustrated by evolutionary diversification of Hawaiian
Ou
birds,require longer timescales covering 100,000 to 1 million years.
Akiapolaau
Major evolutionary trends and periodic mass extinctions occur on
Crested honeycreeper even larger timescales covering tens of millions of years.The fossil
record of horses through the past 50 million years shows a series of
Ula-ai-hawane different species replacing older ones through time and ending with
Apapane the familiar horses that we know today.The fossil record of marine
invertebrates shows a series of mass extinctions separated by intervals
of approximately 26 million years.
The earth bears its own record of the irreversible,historical
change that we call organic evolution.Because every feature of life
is a product of evolutionary processes,biologists consider organic
evolution the keystone of all biological knowledge.
Mamos
liwi
Evolutionary diversification
of Hawaiian honeycreepers.
Hickman & Roberts
Animal Diversity, 2e
McGraw-Hill HE
PG#98-6054
Figure 01.CO
1
Hickman−Roberts−Larson: 1. Science of Zoology and Text © The McGraw−Hill
Animal Diversity, Third Evolution of Animal Companies, 2002
Edition Diversity
2 chapter one
Zoology (Gr.zo¯on,animal,+ logos, discourse on,study brought by the American Civil Liberties Union on behalf of 23
of) is the scientific study of animals.It is a subdivision plaintiffs,including religious leaders and groups representing
of biology (Gr.bios, life,+ logos, discourse on,study several denominations,individual parents,and educational asso-
of),the study of all life.The panorama of animal diversity— ciations.Plaintiffs contended that this law was a violation of the
how animals function,live,reproduce,and interact—is excit- First Amendment to the U.S. Constitution, which prohibits
ing,fascinating,and awe inspiring.A complete understanding establishment of religion by government. This prohibition
of all phenomena included in zoology is beyond the ability of includes passing a law that would aid one religion or prefer one
any single person,perhaps of all humanity,but we strive to religion over another.On January 5,1982,Judge Overton per-
know as much as possible. manently prohibited Arkansas from enforcing Act 590.
To understand the diversity of animal life,we must study Considerable testimony during the trial addressed the
its long history,which began more than 600 million years ago. nature of science. On the basis of testimony by scientists,
From the earliest animals to the millions of animal species liv- Judge Overton stated explicitly these essential characteristics
ing today,this history demonstrates perpetual change,which of science:
we call evolution.We depict the history of animal life as a
1. It is guided by natural law.
branching genealogical tree,called a phylogeny.We place the
2. It has to be explanatory by reference to natural law.
earliest species ancestral to all animals at the trunk;then all liv-
3. It is testable against the empirical world.
ing animal species fall at the growing tips of the branches.
4. Its conclusions are tentative,that is,are not necessarily
Each successive branching event represents formation of new
the final word.
species from an ancestral one.Newly formed species inherit
5. It is falsifiable.
many characteristics from their immediate ancestor,but they
Pursuit of scientific knowledge must be guided by physi-
also evolve new features that appear for the first time in the
cal and chemical laws that govern the state of existence.Scien-
history of life.Each branch therefore has its own unique com-
tific knowledge must explain what is observed by reference to
bination of characteristics and contributes a new dimension to
natural law without requiring intervention of any supernatural
the spectrum of animal diversity.
being or force.We must be able to make observations directly
Scientific study of animal diversity has two major goals.
or indirectly to test hypotheses about nature.We must be ready
The first is to reconstruct a phylogeny of animal life and
to discard or modify any conclusion if it is contradicted by fur-
to find where in evolutionary history we can locate origins
ther observations.As Judge Overton stated,“While anybody is
of multicellularity, a coelom, spiral cleavage, vertebrae,
free to approach a scientific inquiry in any fashion they choose,
homeothermy, and all other features that comprise animal
they cannot properly describe the methodology used as scien-
diversity as we know it.The second major goal is to under-
tific,if they start with a conclusion and refuse to change it
stand historical processes that generate and maintain diverse
regardless of the evidence developed during the course of the
species and adaptations throughout evolutionary history.Dar-
investigation.”Science is outside religion,and results of science
win’s theory of evolution makes possible the application of
do not favor one religious position over another.
scientific principles to attain both goals.
Scientific Method
Principles of Science
These essential criteria of science form the hypothetico-
A basic understanding of zoology requires understanding what deductive method.The first step of this method is to generate
science is,what it is not,and how knowledge is gained using hypotheses, or potential answers to a question being asked.
the scientific method.In this section we examine methodol- These hypotheses are usually based on prior observations of
ogy that zoology shares with science as a whole.These fea- nature (figure 1.1) or derived from theories based on such obser-
tures distinguish sciences from those activities,such as art and vations.Scientific hypotheses often constitute general statements
religion,that we exclude from science. that may explain a large number of diverse observations about
Despite the enormous impact of science on our lives, nature.Natural selection,for example,explains our observations
many people have only a minimal understanding of science. that many different species have properties that adapt them to
Public misunderstanding of scientific principles as applied to their environments.Based on a hypothesis,a scientist must say,“If
studies of animal diversity was evident on March 19,1981, my hypothesis is a valid explanation of past observations,then
when the governor of Arkansas signed into law the Balanced future observations ought to have certain characteristics.”
Treatment for Creation-Science and Evolution-Science Act (Act If a hypothesis is very powerful in explaining a large vari-
590 of 1981).This act falsely presented creation-science as a ety of related phenomena,it attains the status of a theory.Evo-
valid scientific endeavor.Creation-science is a religious posi- lution by natural selection is a good example; it provides a
tion advocated by a minority of America’s religious commu- potential explanation for the occurrence of many different traits
nity and does not qualify as science. distributed among animal species.Each of these instances consti-
Enactment of this law led to a historic lawsuit tried in tutes a specific hypothesis generated from the theory of evolu-
December 1981 in the court of Judge William R.Overton,U.S. tion by natural selection.The most useful theories are those that
District Court, Eastern District of Arkansas. The suit was can explain the largest array of different natural phenomena.
Hickman−Roberts−Larson: 1. Science of Zoology and Text © The McGraw−Hill
Animal Diversity, Third Evolution of Animal Companies, 2002
Edition Diversity
Science of Zoology and Evolution of Animal Diversity 3
all levels of complexity.It includes problems of
explaining how animals perform their metabolic,
physiological,and behavioral functions at molecu-
lar,cellular,organismal,and even population lev-
els. For example, how is genetic information
expressed to guide synthesis of proteins? What
causes cells to divide to produce new cells? How
does population density affect physiology and
behavior of organisms?
Biological sciences that address proximate
A
causes are called experimental sciences be-
cause they use the experimental method.This
method consists of three steps: (1) predicting
how a system being studied will respond to a dis-
turbance,(2) making the disturbance,and then
(3) comparing observed results to predicted
ones. Experimental conditions are repeated to
eliminate chance occurrences that might pro-
duce errors.Controls (repetitions of an experi-
mental procedure that lack the disturbance) are
established to eliminate any unperceived factors
B D
that may bias an experiment’s outcome.
Processes by which animals maintain a
body temperature under different environmental
conditions,digest food,migrate to new habitats,or
store energy are additional examples of phenom-
ena studied using experimental methodology.
Subfields of biology that qualify as experimental
sciences include molecular biology,cell biology,
endocrinology,immunology,physiology,develop-
mental biology,and community ecology.
In contrast to proximate causes, evolu-
C E
tionary sciencesaddress questions of ultimate
figure 1.1 causes that have generated biological systems
A few of the many dimensions of zoological research.A,Observing coral in the Caribbean and their properties through evolutionary time.
Sea.B,Studying insect larvae collected from an arctic pond on Canada’s Baffin Island. For example, what evolutionary factors have
C,Separating growth stages of crab larvae at a marine laboratory.D,Observing nematocyst caused some birds to acquire complex patterns
discharge (E) from hydrozoan tentacles (see p.123). of seasonal migration between temperate and
tropical regions? Why do different species of ani-
We emphasize that the word “theory,”when used by sci- mals have different numbers of chromosomes in their cells?
entists,is not just speculation as often implied by nonscientific Why do some animal species maintain complex social systems,
usage.Failure to make this distinction is prominent in criticism whereas animals of other species remain largely solitary?
of evolution by creationists,who have called evolution “only a Evolutionary sciences proceed largely using the com-
theory”to imply that it is little better than a random guess.In parative method rather than experimentation.Characteris-
fact, evolutionary theory is supported by such massive evi- tics of molecular biology,cell biology,organismal structure,
dence that most biologists view repudiation of evolution as development, and ecology are compared among related
tantamount to repudiation of reality.Nonetheless,evolution, species to identify patterns of variation.Patterns of similarity
like all other theories in science,is not proved by mathemati- and dissimilarity then can be used to test hypotheses of relat-
cal logic,but is testable,tentative,and falsifiable. edness and thereby to reconstruct the evolutionary tree that
relates the species being compared.Comparative studies also
serve to test hypotheses of evolutionary processes that have
Experimental and Evolutionary Sciences
generated animal diversity.Clearly,evolutionary sciences use
The many questions asked about animal life since Aristotle’s results of experimental sciences as a starting point.Evolution-
time can be grouped into two major categories.The first cate- ary sciences include comparative biochemistry, molecular
gory seeks to understand proximate causes(also called imme- evolution, comparative cell biology, comparative anatomy,
diate causes) that underlie functioning of biological systems at comparative physiology,and phylogenetic systematics.
Hickman−Roberts−Larson: 1. Science of Zoology and Text © The McGraw−Hill
Animal Diversity, Third Evolution of Animal Companies, 2002
Edition Diversity
4 chapter one
The Animal Rights Controversy
• • •
In recent years,the debate surrounding use not sufficient.A recent report by the National
of animals to serve human needs has inten- Research Council concedes that although a
sified.Most controversial of all is animal use search for alternatives to animals in research
in biomedical and behavioral research and in and testing will continue,“the chance that
testing commercial products. alternatives will completely replace animals
A few years ago, Congress passed a in the foreseeable future is nil.” Realistic
series of amendments to the Federal Animal immediate goals,however,include reduction
Welfare Act,a body of laws covering animal in number of animals used,replacement of
care in laboratories and other facilities.These mammals with other vertebrates,and refine-
amendments have become known as the ment of experimental procedures to reduce
three R’s: Reduction in number of animals discomfort of animals being tested.
needed for research; Refinement of tech- Medical and veterinary progress depends
niques that might cause stress or suffering; on research using animals. Every drug and
Replacementof live animals with simulations every vaccine developed to improve human
or cell cultures whenever possible. As a health has been tested first on animals.
result,the total number of animals used each Research using animals has enabled medical
year in research and in testing of commercial science to eliminate smallpox and polio,and
products has declined.Developments in cel- to immunize against diseases previously com-
lular and molecular biology also have con- mon and often deadly,including diphtheria,
tributed to decreased use of animals for mumps, and rubella. It also has helped to
research and testing.An animal rights move- create treatments for cancer,diabetes,heart
According to the U.S.Department of Health and
ment,composed largely of vocal antivivisec- disease,and manic-depressive psychoses,and
Human Services,animal research has helped
tionists,has created awareness of needs of to develop surgical procedures including extend our life expectancy by 20.8 years.
animals used in research and has stimulated heart surgery,blood transfusions,and cataract
researchers to discover cheaper, more effi- removal.AIDS research is wholly dependent and later with other animals,opened a new
cient,and more humane alternatives. on studies using animals. The similarity of era in immunological research with vast rami-
However, computers and culturing of simian AIDS,identified in rhesus monkeys,to fications for treatment of disease in humans
cells can simulate effects on organismal sys- human AIDS has permitted simian AIDS to and other animals.
tems of,for instance,drugs,only when the serve as a model for human AIDS. Recent Research using animals also has bene-
basic principles involved are well known. work indicates that cats,too,may be useful fited other animals through the develop-
When principles themselves are being models for developing an AIDS vaccine.Skin ment of veterinary cures.Vaccines for feline
scrutinized and tested,computer modeling is grafting experiments, first done with cattle leukemia and canine parvovirus were first
Origins of Darwinian Pre-Darwinian Evolutionary Ideas
Evolutionary Theory Before the eighteenth century,speculation on the origin of
species rested on myth and superstition, not on anything
Charles Robert Darwin and Alfred Russel Wallace (figure 1.2) resembling a testable scientific hypothesis. Creation myths
were the first to establish evolution as a powerful scientific viewed the world as a constant entity that did not change after
theory.Today organic evolution can be denied only by aban- its creation.Nevertheless,some thinkers approached the idea
doning reason.As the noted English biologist Sir Julian Huxley that nature has a long history of perpetual and irreversible
wrote,“Charles Darwin effected the greatest of all revolutions change.
in human thought,greater than Einstein’s or Freud’s or even Early Greek philosophers,notably Xenophanes,Empedo-
Newton’s,by simultaneously establishing the fact and discov- cles,and Aristotle,developed a primitive idea of evolutionary
ering the mechanism of organic evolution.”Darwinian theory change.They recognized fossils as evidence for former life,
allows us to understand both the genetics of populations and which they believed had been destroyed by natural catastro-
long-term trends in the fossil record.Darwin and Wallace were phe.Despite their spirit of intellectual inquiry,ancient Greeks
not the first,however,to consider the basic idea of organic failed to establish an evolutionary concept, and the issue
evolution,which has an ancient history.We review the history declined well before the rise of Christianity.Opportunities for
of evolutionary thinking as it led to Darwin’s theory and then evolutionary thinking became even more restricted as the bib-
discuss evidence supporting it. lical account of the earth’s creation became accepted as a