Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

Statistical method for testing the neutral mutation hypothesis by DNA polymorphism.

So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

Evolution of Protein Molecules

Genetics and analysis of quantitative traits

The assumption of costs of reproduction were a logical necessity for much of the early development of life history theory. An unfortunate property of 'logical necessities' is that it is easy to also assume that they must be true. What if this does not turn out to be the case? The existence and universality of costs of reproduction were initially challenged with empirical data of questionable value, but later with increasingly strong theoretical and empirical results. Here, we discuss Ken Spitze's 'superfleas', which represent what we consider to be the strongest empirical challenge to the universality of costs, then offer a possible explanation for their existence.

https://www.cell.com/trends/ecology-evolution/pdf/S0169-5347(00)01941-8.pdf

Big houses, big cars, superfleas and the costs of reproduction

The effective population size (Ne ) depends strongly on mating system and generation time. These two factors interact such that, under many circumstances, Ne is close to N/2, where N is the number of adults. This is shown to be the case for both simple and highly polygynous mating systems. The random union of gametes (RUG) and monogamy are two simple systems previously used in estimating Ne , and here a third, lottery polygyny, is added. Lottery polygyny, in which all males compete equally for females, results in a lower Ne than either RUG or monogamy! Given nonoverlapping generations the reduction is 33% for autosomal loci and 25% for sex-linked loci. The highly polygynous mating systems, harem polygyny and dominance polygyny, can give very low values of Ne /N when the generation time (T) is short. However, as T is lengthened, Ne approaches N/2. The influence of a biased sex ratio depends on the mating system and, in general, is not symmetrical. Biases can occur because of sex differences in either survival or recruitment of adults, and the potential for a sex-ratio bias to change Ne is much reduced given a survival bias. The number of juveniles present also has some influence: as the maturation time is lengthened, Ne increases.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1558-5646.1993.tb02158.x

The influence of mating system and overlapping generations on effective population size.

The discussion of a population's minimum viable size provides a focus for the study of ecological and genetic factors that influence the persistence of a threatened population. There are many causes of extinction and the fate of a specific population cannot generally be predicted. This uncertainty has been dealt with in two ways: through stochastic demographic models to determine how to minimize extinction probabilities; and through population genetic theory to determine how best to maintain genetic variation, in the belief that the ability to evolve helps buffer a population against the unknown. Recent work suggests that these two very different approaches lead to very similar conclusions, at least under panmictic conditions. However, defining the ideal spatial distribution for an endangered species remains an important challenge.

Assessing minimum viable population size: Demography meets population genetics

Accurate estimation of effective population size is important in attempts to conserve small populations of animals or plants. We review the genetic and ecological methods that have been used to estimate effective population size in the past and suggest that, while genetic methods may often be appropriate for the estimation of Ne, and its monitoring, ecological methods have the advantage of providing data that can help predict the effect of a changed environment on Ne. Estimation of Ne, is particularly complex in populations with overlapping generations, and we summarize previous empirical estimates of Ne that used ecological methods in such populations. Since it is often difficult to assess what parameters and assumptions have been used in previous calculations, we suggest a method that provides a good estimate of Ne, makes clear what assumptions are involved, and yet requires a minimum of information. The method is used to analyze data from 14 studies. In 36% (5) of these studies, our estimate is in excellent agreement with the original, and yet we use significantly less information, in 21% (3) the original estimate is markedly lower, in 43% (6) it is markedly higher. Reasons for the discrepancies are suggested. Two of the underestimates involve a failure in the original to account for a long maturation time, and four of life overestimates involve problems in the original with the correction for overlapping generations.



La estimacion precisa del tamano poblacional efectivo es importante en los intentos de conservar pequenas poblaciones de animales y plantas. Nosotros revisamos los metodos geneticos y ecologicos que han sido ultizados en el pasado para estimar el tamano poblacional efectivo y sugerimos que si bien frecuentemente los metodos geneticos serian apropiados para la estimacion y monitoreo de Ne, los metodos ecologicos tienen la ventaja de proveer datos que pueden ayudar a predecir el efecto de cambios ambientales sobre el Ne. La estimacion del Ne es particularmente compleja en poblaciones con generaciones superpuestas y nosotros resumimos estimaciones empiricas de Ne anteriores que usaron metodos ecologicos en tales poblaciones. Dado que muchas veces es dificil evaluar que parametros y suposiciones han sido usados en calculos previos, nosotros sugerimos un metodo que provee una buena estimacion de Ne, pone en claro que supuestos estan involucrados y sin embargo requiere un minimo de informacion. El metodo es usado para analizar datos de catorce estudios. En un 36% de los casos (5), nuestro estimador concuerda excelentemente con el original a pesar de usar una cantidad significativamente menor de informacion; en un 21% (3) la estimacion original es marcadamente menor, y en un 43% (6) es marcadamente mayor. Se sugieren razones para estas discrepancias. Dos de las subestimaciones involucran una falla en la consideracion de un tiempo de maduracion largo en la estimacion original, y cuatro de las sobreestimaciones involucran problemas en la correccion por generaciones superpuestas en la estimacion original.

Estimating the effective population size of conserved populations

Effective population size (N(e)) determines the strength of genetic drift in a population and has long been recognized as an important parameter for evaluating conservation status and threats to genetic health of populations. Specifically, an estimate of N(e) is crucial to management because it integrates genetic effects with the life history of the species, allowing for predictions of a population's current and future viability. Nevertheless, compared with ecological and demographic parameters, N(e) has had limited influence on species management, beyond its application in very small populations. Recent developments have substantially improved N(e) estimation; however, some obstacles remain for the practical application of N(e) estimates. For example, the need to define the spatial and temporal scale of measurement makes the concept complex and sometimes difficult to interpret. We reviewed approaches to estimation of N(e) over both long-term and contemporary time frames, clarifying their interpretations with respect to local populations and the global metapopulation. We describe multiple experimental factors affecting robustness of contemporary N(e) estimates and suggest that different sampling designs can be combined to compare largely independent measures of N(e) for improved confidence in the result. Large populations with moderate gene flow pose the greatest challenges to robust estimation of contemporary N(e) and require careful consideration of sampling and analysis to minimize estimator bias. We emphasize the practical utility of estimating N(e) by highlighting its relevance to the adaptive potential of a population and describing applications in management of marine populations, where the focus is not always on critically endangered populations. Two cases discussed include the mechanisms generating N(e) estimates many orders of magnitude lower than census N in harvested marine fishes and the predicted reduction in N(e) from hatchery-based population supplementation.

/pdf/understanding-and-estimating-effective-population-size-for-4tswtxr5hp.pdf

Leonard Nunney

Papers

Big houses, big cars, superfleas and the costs of reproduction

The influence of mating system and overlapping generations on effective population size.

Assessing minimum viable population size: Demography meets population genetics

Estimating the effective population size of conserved populations

Understanding and Estimating Effective Population Size for Practical Application in Marine Species Management