Evolution's Wedge

David W. Pfennig is Professor of Biology at the University of North Carolina. Karin S. Pfennig is Associate Professor of Biology at the University of North Carolina.

"Fresh... Well documented and easily accessible... Highly recommended." -- F. T. Kuserk, Moravian College Choice "Enjoyable to read... [Evolution's Wedge is] a valuable resource for any student or established researcher with an interest in Earth's biological diversity." -- Alexander Pigot BioScience "A welcome addition to the discussion." -- Richard A. Richards The Quarterly Review of Biology "A significant contribution to this aspect of the current study of evolution, Evolution's Wedge brings to the fore the potential importance of character displacement as a macro-evolutionary process." -- Brian Livingstone Zoological Journal of The Linnean Society

• Preface 1. Discovery of a Unifying Principle Introduction A Brief History Detecting Character Displacement Phenomena Mistaken for Character Displacement What Constitutes Character Displacement? Conflation of Process and Pattern Reproductive Character Displacement versus Reinforcement Terminology A Unifying Principle Summary Further Reading Box 1.1: Alternative Manifestations of Character Displacement Box 1.2: Suggestions for Future Research 2. Why Character Displacement Occurs Introduction Why Ecological Character Displacement Occurs RESOURCE COMPETITION COMPETITIVE EXCLUSION SPECIES COEXISTENCE RESOURCE PARTITIONING VIA CHARACTER DISPLACEMENT VS. SPECIES SORTING Why Reproductive Character Displacement Occurs REPRODUCTIVE COMPETITION REPRODUCTIVE EXCLUSION REPRODUCTIVE PARTITIONING VIA CHARACTER DISPLACEMENT VS. SPECIES SORTING Summary Further Reading Box 2.1: Alternative Models of Species Coexistence Box 2.2: Is Competitively Induced Plasticity Character Displacement? Box 2.3: Suggestions for Future Research 3. When Character Displacement Occurs Introduction Facilitators of Character Displacement STANDING VARIATION STRONG SELECTION ECOLOGICAL OPPORTUNITY LACK OF ANTAGONISTIC GENETIC CORRELATIONS GENE FLOW INITIAL DIFFERENCES Variation in the Expression of Character Displacement How Ecological and Reproductive Character Displacement Facilitate Each Other ECOLOGICAL DIVERGENCE AS A FACILITATOR OF REPRODUCTIVE DIVERGENCE REPRODUCTIVE DIVERGENCE AS A FACILITATOR OF ECOLOGICAL DIVERGENCE WHY ONE FORM IS NECESSARY TO FACILITATE THE OTHER How Ecological and Reproductive Character Displacement Can Impede Each Other Summary Further Reading Box 3.1: Suggestions for Future Research 4. How Character Displacement Unfolds Introduction Mechanisms of Divergence GENETICALLY CANALIZED DIVERGENCE ENVIRONMENTALLY INDUCED DIVERGENCE Tempo and Mode of Character Displacement HOW MECHANISMS DIFFER IN SPEED OF DIVERGENCE THE PLASTICITY-FIRST HYPOTHESIS EMPIRICAL TESTS OF THE PLASTICITY-FIRST HYPOTHESIS Summary Further Reading Box 4.1: Suggestions for Future Research 5. Diversity and Novelty Within Species Introduction How Intraspecific Character Displacement Works Intraspecific Character Displacement: Observational Evidence Intraspecific Character Displacement: Experimental Evidence Evolution of Alternative Phenotypes FREQUENCY-DEPENDENT DISRUPTIVE SELECTION AND THE EVOLUTION OF ALTERNATIVE PHENOTYPES EVOLUTION OF RESOURCE POLYMORPHISM EVOLUTION OF MATING POLYMORPHISM Intraspecific Character Displacement and Species Diversity Character Displacement Within Versus Between Species Summary Further Reading Box 5.1: Suggestions for Future Research 6. Ecological Consequences Introduction Evolution of the Niche Partitioning of Resources and Reproduction: A Reprise Community Organization Character Displacement and Darwinian Extinction Species Distributions and Geographic Mosaics Character Displacement and Species Ranges Summary Further Reading Box 6.1: Individual Variation and the Coexistence of Species Box 6.2: Suggestions for Future Research 7. Sexual Selection Introduction How Sexual Selection Works How Character Displacement Affects Sexual Selection EFFECTS OF PHENOTYPIC SHIFTS EFFECTS OF HABITAT SHIFTS Implications of Character Displacement's Effects on Sexual Selection How Sexual Selection Affects Character Displacement A Cautionary Note: Process Versus Pattern Summary Further Reading Box 7.1: Suggestions for Future Research 8. Speciation Introduction What are Species? How are Species Boundaries Maintained? Evolution of Isolating Mechanisms Character Displacement's Role in Speciation HOW CHARACTER DISPLACEMENT FINALIZES SPECIATION HOW CHARACTER DISPLACEMENT INITIATES SPECIATION HOW INTRASPECIFIC CHARACTER DISPLACEMENT INITIATES SPECIATION Summary Further Reading Box 8.1: Selection and the Evolution of Reproductive Isolation Box 8.2: Suggestions for Future Research 9. Macroevolution Introduction Competition in the Fossil Record Methods for Studying Macroevolution: Rewinding the Tape of Life Adaptive Radiation SPECIES PROLIFERATION DIVERGENT EVOLUTION Evolutionary Escalation Macroevolution: Red Queen or Court Jester? Summary Further Reading Box 9.1: Suggestions for Future Research 10. Major Themes and Unsolved Problems Introduction Major Themes of the Book CHARACTER DISPLACEMENT IS A PROCESS, NOT A PATTERN CHARACTER DISPLACEMENT CAN PRODUCE DIFFERENT FORMS OF TRAIT EVOLUTION ECOLOGICAL AND REPRODUCTIVE CHARACTER DISPLACEMENT INTERACT PHENOTYPIC PLASTICITY CAN MEDIATE CHARACTER DISPLACEMENT CHARACTER DISPLACEMENT PROMOTES DIVERSIFICATION AT MULTIPLE LEVELS CHARACTER DISPLACEMENT AND SEXUAL SELECTION INTERACT CHARACTER DISPLACEMENT HAS MACROEVOLUTIONARY IMPLICATIONS Some Unsolved Problems Summary