Variation -- Variation -- CONTENTS -- Variation and Variability: Central Concepts in Biology -- REFERENCES -- Variation from Darwin to the Modern Synthesis -- INTRODUCTION -- I. VARIATION BEFORE DARWIN -- II. DARWIN AND VARIATION -- III. ALTERNATIVE THEORIES OF VARIATION AND EVOLUTION -- IV. NEO-DARWINISM -- V. THE EVOLUTIONARY SYNTHESIS -- VI. CONCLUSIONS -- REFERENCES -- The Statistics of Variation -- ABSTRACT -- INTRODUCTION -- I. ABSOLUTE VARIATION: UNIVARIATE CASE -- II. ABSOLUTE VARIATION: MULTIVARIATE CASE -- III. RELATIVE VARIATION: UNIVARIATE CASE -- IV. RELATIVE VARIATION: MULTIVARIATE CASE -- V. DIMENSIONALITY OF VARIATION -- VI. TIGHTNESS -- VII. MEASUREMENT ERROR AND SINGLE SPECIMENS -- REFERENCES -- Landmark Morphometrics and the Analysis of Variation -- INTRODUCTION -- I. COORDINATE DATA AND THE COORDINATE SYSTEM -- II. THE GENERAL PERTURBATION MODEL FOR LANDMARK VARIATION -- III. PROPER ELIMINATION OF NUISANCE PARAMETERS USING A COORDINATE SYSTEM INVARIANT METHOD OF ESTIMATION -- IV. ADDING ASSUMPTIONS TO THE PERTURBATION MODEL -- V. CONCLUSIONS -- ACKNOWLEDGMENTS -- REFERENCES -- Variation in Ontogeny -- INTRODUCTION -- I. MEASURING VARIATION: A CASE STUDY -- II. IMPLICATIONS FOR STUDIES OF VARIATION -- III. CONCLUSIONS -- ACKNOWLEDGMENTS -- REFERENCES -- Constraints on Variation from Genotype through Phenotype to Fitness -- INTRODUCTION -- I. RNA EVOLUTIONARY MODEL -- II. EVOLVING CONSTRAINTS ON VARIATION IN RNA -- III. MECHANISTIC CONSTRAINTS -- IV. EPISTATIC CONSTRAINTS -- V. VIABILITY CONSTRAINTS -- VI. MODULARITY: A WAY OUT OF THE CONSTRAINTS -- ACKNOWLEDGMENTS -- REFERENCES -- Developmental Origins of Variation -- INTRODUCTION -- I. DOES INTRINSIC DEVELOPMENTAL VARIATION EXIST? -- II. INTRINSIC VARIATION IN DIFFERENT ENVIRONMENTS -- III. POTENTIAL ORIGINS OF INTRINSIC DEVELOPMENTAL VARIATION.

IV. AN EXAMPLE OF NOISE IN EUKARYOTIC TRANSCRIPTION -- V. NOISY BICOID GENE EXPRESSION IN FRUIT FLIES -- VI. NOISE IN ASYMMETRY PRODUCTION -- VII. NOISY IMPLICATION FOR EVOLUTION -- VIII. NETWORKS -- IX. MORPHOGENETIC FIELDS: A POTENTIAL SOURCE OF VARIATION -- X. IMPLICATIONS -- XI. SUMMARY -- ACKNOWLEDGMENTS -- REFERENCES -- Canalization, Cryptic Variation, and Developmental Buffering: A Critical Examination and Analytical Perspective -- INTRODUCTION -- I. A REVIEW OF THE REVIEWS -- II. EMPIRICAL CONCERNS FOR THE STUDY OF CANALIZATION -- III. DEFINITIONS OF CANALIZATION -- IV. REACTION NORM OF THE MEAN (RxNM) DEFINITION OF CANALIZATION -- V. THE VARIATION APPROACH TO CANALIZATION -- VI. PARTITIONING SOURCES OF VARIATION -- VII. INFERRING CANALIZATION: WHEN IS A TRAIT CANALIZED? -- VIII. WHAT ARE THE APPROPRIATE TESTS FOR MAKING STATISTICAL INFERENCES ABOUT CANALIZATION? -- IX. IN THE INTERIM ÷ -- X. ANALYSIS FOR THE RxNM APPROACH -- XI. THE ANALYSIS OF CRYPTIC GENETIC VARIATION -- XII. MAPPING CRYPTIC GENETIC VARIANTS -- XIII. IS THE GENETIC ARCHITECTURE OF CRYPTIC GENETIC VARIATION DIFFERENT FROM THAT OF OTHER GENETIC VARIATION INVOLVED WITH TRAIT EXPRESSION? -- XIV. NOW THAT I HAVE ALL OF THIS CRYPTIC GENETIC VARIATION, WHAT DO I DO WITH IT? -- XV. THE FUTURE FOR STUDIES OF CANALIZATION -- ACKNOWLEDGMENTS -- REFERENCES -- Mutation and Phenotypic Variation: Where is the Connection? Capacitators, Stressors, Phenotypic Variability, and Evolutionary Change -- ABSTRACT -- INTRODUCTION: VARIABILITY AND LIMITS -- I. MUTATORS, RECOMBINATORS, STRESSORS, AND GENETIC VARIABILITY -- II. RECOMBINATION -- III. THE IMPACT OF NEW MUTANTS AND RECOMBINANTS: CANALIZATION AND CAPACITATORS -- IV. IN SEARCH OF CAPACITATORS: GENES THAT INFLUENCE DEVELOPMENTAL STABILITY AND CANALIZATION -- V. CAPACITATORS, STRESSORS, AND QUANTITATIVE VARIATION.

VI. DO WE NEED VARIABILITY GENERATORS? -- VII. CONCLUDING REMARKS: EXPERIMENTAL PROGRAMS FOR DEFINING THE ROLE OF VARIABILITY GENERATORS -- REFERENCES -- Within Individual Variation: Developmental Noise versus Developmental Stability -- INTRODUCTION -- I. CAUSES OF DEVELOPMENTAL NOISE -- II. MECHANISMS OF DEVELOPMENTAL STABILITY -- III. IMPLICATIONS -- REFERENCES -- Developmental Constraints, Modules, and Evolvability -- ABSTRACT -- INTRODUCTION -- I. EVOLVABILITY AND CONSTRAINTS -- II. INTEGRATION AND MODULARITY -- III. DEVELOPMENTAL ORIGINS OF COVARIATION AMONG TRAITS -- IV. DEVELOPMENTAL INTERACTIONS AND PLEIOTROPY -- V. EVOLUTION OF PLEIOTROPY AND DEVELOPMENTAL INTERACTIONS -- VI. MODULARITY OF PLEIOTROPIC EFFECTS: INHERENT IN DEVELOPMENTAL SYSTEMS OR EVOLVED PROPERTY? -- VII. FROM PLEIOTROPIC GENE EFFECTS TO G MATRICES -- VIII. G MATRICES, CONSTRAINTS, AND EVOLUTIONARY DYNAMICS -- IX. PERSPECTIVE: DEVELOPMENTAL PROCESSES AND EVOLUTIONARY CONSTRAINTS -- ACKNOWLEDGMENTS -- REFERENCES -- Developmental Regulation of Variability -- INTRODUCTION -- I. EMPIRICAL PATTERNS -- II. THE ONTOGENY OF VARIATION IN MALE NORWAY RAT CRANIAL SHAPE -- III. BIOLOGICAL PATTERNS VERSUS ARTIFACTS -- IV. MECHANISMS GENERATING AND REGULATING CRANIOFACIAL SHAPE VARIANCE -- V. TARGETED GROWTH -- VI. ORGANISMAL DEVELOPMENTAL TIMING -- VII. VARIATION IN RELATIVE DEVELOPMENTAL TIMING OF MODULES -- VIII. NEURAL REGULATION OF MUSCULOSKELETAL INTERACTIONS -- IX. CANALIZED SHAPE AS AN EPIPHENOMENON -- ACKNOWLEDGMENTS -- REFERENCES -- Role of Stress in Evolution: From Individual Adaptability to Evolutionary Adaptation -- INTRODUCTION -- I. EVOLUTION OF RESPONSE TO STRESS -- II. EVOLUTIONARY CONSEQUENCES OF STRESS -- III. EVOLUTIONARY ADAPTATION -- IV. CONCLUSIONS -- ACKNOWLEDGMENTS -- REFERENCES -- Environmentally Contingent Variation: Phenotypic Plasticity and Norms of Reaction.

INTRODUCTION -- I. PLASTICITY CONCEPTS -- II. THE GENETIC AND DEVELOPMENTAL BASIS OF PHENOTYPIC PLASTICITY -- III. HOW PLASTICITY INTERACTS WITH CONSERVED DEVELOPMENTAL PATTERNS -- IV. WHAT EFFECTS DOES PLASTICITY HAVE ON POPULATIONS AND COMMUNITIES? -- V. RESEARCH AGENDA -- ACKNOWLEDGMENTS -- REFERENCES -- Variation and Life-History Evolution -- INTRODUCTION -- II. PHENOTYPIC VARIATION IN A STOCHASTIC ENVIRONMENT -- III. PREDICTABLE ENVIRONMENTS -- IV. CONCLUDING COMMENTS -- REFERENCES -- Antisymmetry -- INTRODUCTION -- I. ASYMMETRY TERMINOLOGY -- II. THE HISTORY OF ANTISYMMETRY -- III. TAXONOMIC DISTRIBUTION AND FUNCTIONAL SIGNIFICANCE OF ANTISYMMETRY -- IV. DEVELOPMENT AND REGENERATION OF ASYMMETRY IN ANTISYMMETRIC SPECIES -- V. INHERITANCE OF DIRECTION IN ANTISYMMETRIC SPECIES -- VI. INHERITANCE OF DIRECTION IN DIRECTIONALLY ASYMMETRIC SPECIES -- VII. EVOLUTIONARY SIGNIFICANCE OF ANTISYMMETRY -- VIII. WHAT NEXT? -- ACKNOWLEDGMENTS -- REFERENCES -- Variation in Structure and Its Relationship to Function: Correlation, Explanation, and Extrapolation -- ABSTRACT -- INTRODUCTION -- I. BACKGROUND -- II. APPROACHES TO THE STUDY OF STRUCTURAL VARIATION -- III. VARIATION AS AN OBSERVABLE PHENOMENON -- IV. IN SITU CORRELATIONAL STUDIES OF THE RELATIONSHIP BETWEEN STRUCTURAL VARIATION AND FUNCTIONAL ATTRIBUTES -- V. EX SITU STUDIES OF THE RELATIONSHIP BETWEEN STRUCTURAL VARIATION AND PERFORMANCE -- VI. CONCLUDING REMARKS -- REFERENCES -- A Universal Generative Tendency toward Increased Organismal Complexity -- INTRODUCTION -- I. INTERNAL VARIANCE AS COMPLEXITY -- II. THREE SIMPLE MODELS -- III. THE EFFECT OF INCREASED DIMENSIONALITY -- IV. APPARENT DIFFICULTIES -- V. IS THERE AN UPWARD BIAS IN REAL LINEAGES? -- VI. IF SO, THE PRINCIPLE IS SUPPORTED -- VII. IF NOT, WHY NOT? -- VIII. TESTING THE PRINCIPLE -- IX. A REVERSAL OF INTUITION -- REFERENCES.

Variation and Versatility in Macroevolution -- I. PRINCIPLES -- II. EXAMPLES -- III. OVERVIEW AND CONCLUSION -- ACKNOWLEDGMENTS -- REFERENCES -- Variation and Developmental Biology: Prospects for the Future -- INTRODUCTION -- I. MODEL ORGANISMS: EXPANDING THE FOLD -- II. ECOLOGICALLY SIGNIFICANT DIFFERENCES IN FORM BETWEEN SPECIES -- III. HOW MANY WAYS TO MAKE A PHENOTYPE: DEVELOPMENTAL VARIATION AND MORPHOLOGICAL SIMILARITY -- IV. INTRASPECIFIC DEVELOPMENTAL VARIATION: CANALIZATION AND DEVELOPMENTAL PLASTICITY -- V. CONCLUSIONS -- REFERENCES -- Phenogenetics: Genotypes, Phenotypes, and Variation -- INTRODUCTION -- I. MECHANISM VERSUS VARIATION -- II. FROM GENOTYPE TO PHENOTYPE: MECHANISM -- III. FROM GENOTYPE TO PHENOTYPE: VARIATION -- IV. SUMMARY -- ACKNOWLEDGMENTS -- REFERENCES -- The Study of Phenotypic Variability: An Emerging Research Agenda for Understanding the Developmental Ò Genetic Architecture Underlying Phenotypic Variation -- INTRODUCTION -- I. VARIABILITY AND THE BIOLOGICAL HIERARCHY -- II. COMPONENTS OF VARIABILITY -- III. CURRENT APPROACHES TO UNDERSTANDING THE DEVELOPMENT Ò GENETIC ARCHITECTURE OF VARIABILITY -- IV. A DEVELOPMENTAL SYSTEMS APPROACH TO PHENOTYPIC VARIABILITY -- V. CONCLUSION -- REFERENCES -- Index.