Introduction to population biology

PART I Evolution by natural selection 1 Chapter 1 Darwin concludes that organisms evolve 3 1.1 Charles Darwin: some important early influences (1809--31) 3 1.2 The earth’s crust: uniformitarian and catastrophist theories 9 1.3 The voyage of the Beagle (1831--6) 13 1.4 Island biogeography provides the key (1836--7) 17 Chapter 2 Darwin’s theories of evolution 19 2.1 Darwin’s evolutionary theories: The Origin of Species (1859) 20 2.2 Darwin’s hesitation to publish, and the reaction to his theories 31 Chapter 3 Understanding natural selection 33 3.1 Some philosophical considerations 34 3.2 Is natural selection a valid scientific theory? 37 3.3 The argument from design 39 3.4 Explaining the seemingly impossible 42 PART II Simple population growth models and their simulation 51 Chapter 4 Density-independent growth and overproduction 53 4.1 Introducing density-independent growth 54 4.2 Growth at discrete time intervals: geometric growth 54 4.3 Simulating geometric growth 57 4.4 Continuous growth through time: exponential growth 58 4.5 Simulating exponential growth 60 4.6 The population bomb 60 4.7 Examples of exponential growth 61 4.8 Problems 63 Appendix 4.1 Simulation of geometric growth 65 Appendix 4.2 Simulation of exponential growth 67 vi CONTENTS Chapter 5 Density-dependent growth, and the logistic growth model 68 5.1 Logistic growth model 68 5.2 Simulating logistic growth 70 5.3 Time lags 72 5.4 Varying the carrying capacity 74 5.5 Analysing population growth 75 5.6 Summary and conclusions 80 5.7 Problems 81 Appendix 5.1 Simulating logistic growth 82 Appendix 5.2 Simulating a discrete form of the logistic growth model 83 Appendix 5.3 Fitting logistic growth curves to data 83 PART III Population genetics and evolution 85 Chapter 6 Gene frequencies and the Hardy–Weinberg principle 87 6.1 Terminology 87 6.2 Frequencies of alleles, genotypes and phenotypes 88 6.3 The Hardy--Weinberg principle 89 6.4 Applying the Hardy--Weinberg principle to autosomal genes with two alleles 91 6.5 Complications 95 6.6 Summary and conclusions 98 6.7 Problems 98 Chapter 7 Mutation and the genetic variation of populations 100 7.1 Gene mutations 100 7.2 The randomness of mutations 102 7.3 Mutation rates and evolution 105 7.4 Genetic variation of populations 108 7.5 Mutations and variability 113 7.6 Summary and conclusions 114 Chapter 8 Small populations, genetic drift and inbreeding 116 8.1 Genetic drift in idealized populations 117 8.2 Effective population size 121 8.3 Empirical examples of genetic drift 122 CONTENTS vii 8.4 Genetic drift in relation to mutation, migration and selection 127 8.5 Inbreeding 128 8.6 Summary and conclusions 134 Chapter 9 Migration, gene flow and the differentiation of populations 135 9.1 Island models 136 9.2 Simulation of island model and general conclusions 139 9.3 Stepping-stone model 141 9.4 Problems 143 Appendix 9.1 Simulating the island model 144 Appendix 9.2 Simulating the stepping-stone model 144 Chapter 10 Quantifying natural selection: haploid and zygotic selection models 146 10.1 Defining fitness and selection 146 10.2 Selection in action 147 10.3 Modelling haploid selection 148 10.4 Zygotic selection models 152 10.5 Using selection models 160 Appendix 10.1 Derivation of haploid selection equations 160 Appendix 10.2 Simulating haploid selection 161 Appendix 10.3 Simulating zygotic selection 163 Chapter 11 Applying zygotic selection models to natural systems 166 11.1 Estimating fitness and selection 166 11.2 The application of zygotic selection models to natural selection 171 11.3 Summary 183 11.4 Problems 184 Chapter 12 Polygenic inheritance, quantitative genetics and heritability 186 12.1 Polygenic inheritance 187 12.2 Partitioning phenotypic variation into different components 188 12.3 Heritability 192 12.4 Response to selection 194 12.5 Empirical examples of selection of quantitative characters 196 viii CONTENTS 12.6 Intelligence, race and societal class 198 12.7 Summary 204 12.8 Problems 204 Chapter 13 Population genetics: summary and synthesis 206 13.1 Mutations 206 13.2 Genetic recombination 208 13.3 Chance effects: genetic drift and inbreeding 209 13.4 Migration: gene flow 210 13.5 Natural selection 210 13.6 Summary 213 PART IV Demography 215 Chapter 14 Life tables and age-specific death rates 217 14.1 Age-specific death rates 217 14.2 Constructing life tables 221 14.3 Comparison of life tables 228 14.4 Constructing life tables using a spreadsheet 228 Appendix 14.1 Constructing life tables using a spreadsheet 229 Chapter 15 Age-specific reproduction and population growth rates 231 15.1 Calculating population growth rates from age-specific birth and death rates 231 15.2 Calculating age-structured population growth rates using spreadsheets 236 15.3 Matrix models 236 15.4 Summary 241 15.5 Problems 241 Appendix 15.1 Calculating growth rates for age-structured populations 242 Appendix 15.2 Simulation of the matrix model 243 Chapter 16 Evolution of life histories 245 16.1 Evolution of age-specific death rates 246 16.2 Evolution of age-specific fertility 251 16.3 Life-history strategies: r- and K-selection 258 16.4 Summary 261 CONTENTS ix PART V Interactions between species, and the behaviour of individuals 263 Chapter 17 Interspecific competition and amensalism 265 17.1 Defining competition 265 17.2 Types of competition 266 17.3 The Lotka--Volterra model of interspecific competition 270 17.4 Simulating competition between two species 280 17.5 The utility of the Lotka--Volterra competition model 281 17.6 Interspecific competition and community structure 282 17.7 Summary 289 17.8 Problems 290 Appendix 17.1 Simulating interspecific competition 290 Chapter 18 Predation 292 18.1 The Lotka--Volterra model of predation 292 18.2 Simulating the Lotka--Volterra predation model 295 18.3 Laboratory experiments 296 18.4 The Rosenzweig and MacArthur graphical model of predation 300 18.5 The functional response of predators 302 18.6 Predation and evolution: prey characteristics that reduce the risk of predation 307 18.7 Summary 316 Appendix 18.1 Simulating the Lotka--Volterra predation model 317 Chapter 19 Animal behaviour, natural selection and altruistic traits 318 19.1 The genetic basis of behaviour 319 19.2 Behaviours that appear contrary to the theory of natural selection 321 Chapter 20 Sexual selection and mating systems 336 20.1 Sexual conflict and competition 336 20.2 Sexual dimorphism and sexual selection 339 20.3 Animal mating systems 345 20.4 Conclusions 351 Chapter 21 Epilogue 354 Glossary 357 Solutions to problems 367 References