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

This book is the second of two volumes in a series on terrestrial and marine comparisons, focusing on the temporal complement of the earlier spatial analysis of patchiness and pattern (Levin et al. 1993). The issue of the relationships among pattern, scale, and patchiness has been framed forcefully in John Steele’s writings of two decades (e.g., Steele 1978). There is no pattern without an observational frame. In the words of Nietzsche, “There are no facts… only interpretations.”

https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.2307/1941447

The Problem of Pattern and Scale in Ecology: The Robert H. MacArthur Award Lecture

Identification of the selective forces on plant dispersal engenders theoretical argument, empirical study, and speculation. We separate evidence, testable hypotheses, and conjecture surrounding two major questions in dispersal ecology. The first asks what ecological, and ultimately evolutionary, advantages exist in seed dispersal. Astonishingly little is known about the advantages to a parent plant that are actually conferred by investment in dispersal structures. Does dispersal enable seeds and ultimately seedlings to escape mortality near the parent? Is continual recolonization of unstable habitats the primary advantage? Must seeds find rare microhabitats suitable for reestablishment? Such issues are addressed through joint consideration of dispersal and establishment-those stages both mediated by parental provisioning and subject to the highest mortality in the life of a plant. The second broad question asks what general and explicit environmental forces influence the timing and mode of dispersal. Do climates or seasons favor one dispersal mode over another? Do differences in number, size, morphology, or nutritional quality of fruits influence frugivore choice, and consequently differential dispersal of species or individuals within species? Studies of dispersal process and mode should be intimately connected. A general objective of this paper is to explore the degree to which they are integrated and, in so doing, to catalyze their union. We emphasize topics most in need of critical attention: the evolutionary ecology of dispersal process and mode. Excellent recent reviews consider such related topics as dispersal mechanism (131, 184), seed dormancy (1, 30), phytogeography (11, 115, 146), masting and predator satiation (105, 156), and succession (68, 69, 189).

https://www.jstor.org/stable/info/2097067

Ecology of Seed Dispersal

The harmful effects of close inbreeding have been noticed for many centuries (34, 35, 165). With the rise of Mendelian genetics, it was realized that the main genetic consequence of inbreeding is homozygosis (165, Ch. 2). Two main theories were early proposed to account for inbreeding depression and its converse, heterosis (the increase in vigor observed in an F1 between two inbred lines). These are the overdominance and partial dominance hypotheses, discussed in more detail below. Research into this question has continued up to the present, and this is one of the topics that we discuss. Darwin (35, 36) was the first to point out that the evident adaptations of many plants for ensuring outcrossing could be understood in terms of the selective advantage of avoiding inbreeding depression. We review the evidence that the evolution of breeding systems of animals and plants has been significantly influenced by the occurrence of inbreeding depression. In order to do this, we consider the contemporary genetic theory of inbreeding depression and heterosis, and the experimental data concerning the strength of inbreeding depression. We emphasize data and theory relevant to natural, rather than domesticated, populations as we are chiefly concerned to evaluate the evolutionary significance of inbreeding depression. We do not attempt to give a complete bibliography of this very extensive field but try to concentrate on what seem to be the most significant findings in relation to this aim.

https://www.jstor.org/stable/pdf/2097132.pdf

Inbreeding depression and its evolutionary consequences

Although the potential genetic risks associated with rare or endangered plants and small populations have been discussed previously, the practical role of population genetics in plant conservation remains unclear. Using theory and the available data, we examine the effects of genetic drift, inbreeding, and gene flow on genetic diversity and fitness in rare plants and small populations. We identify those circumstances that are likely to put these plant species and populations at genetic risk. Warning signs that populations may be vulnerable include changes in factors such as population size, degree of isolation, and fitness. When possible, we suggest potential management strategies.

/pdf/population-genetic-consequences-of-small-population-size-3onkvtfxng.pdf

POPULATION GENETIC CONSEQUENCES OF SMALL POPULATION SIZE: Implications for Plant Conservation

A mixed mating model for many unlinked loci is described. A procedure for estimation of the model parameters (outcrossing rate and gene frequencies), based on a multilocus maximum likelihood equation, is discussed and analyzed for bias, variance, and robustness. Genotypic data from families of known or unknown maternal parentage, or data from progenies of known maternal parentage, are used for estimation. The procedure is applicable to dominant or co-dominant Mendelian genes with two or three alleles per locus, and should be particularly useful in studies where the effort in scoring more loci is less than the effort in scoring more progeny. Variances of the multilocus estimates of outcrossing rate and pollen pool gene frequencies decrease when more loci are included in the estimation. Monte Carlo simulations showed the estimates to be unbiased when model assumptions are not violated, but the bias introduced by various violations is reduced when more loci are included in the estimate. Often the variance of a three or four locus estimate closely approaches the minimum variance possible (the variance of an estimate using infinitely many loci), setting a practical limit to the number of loci needed for a nearly minimum variance estimate. An example from some work on Limnanthes is presented to illustrate the use of multilocus model and its fit to data from natural populations.

/pdf/a-model-for-the-estimation-of-outcrossing-rate-and-gene-2bmqsg89ec.pdf

A model for the estimation of outcrossing rate and gene frequencies using n independent loci

Genetic structure of populations.

Evolutionary divergence among adjacent plant populations I. The evidence and its theoretical analysis

/pdf/evolutionary-divergence-among-adjacent-plant-populations-i-45cz10cduy.pdf

Topics in plant population biology , Topics in plant population biology , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Topics in Plant Population Biology

In order to test whether inbreeders are better colonizers, the Flora of the British Isles was surveyed for tabulating the distribution of colonizers and noncolonizers in relation to breeding systems and longevity. Several criteria and difficulties associated with such comparative surveys are briefly discussed. No overwhelming evidence for association was found between longevity and colonizing ability although predominant selfing was found to be significantly more common among the colonizers. However, such evidence for associations among various genetic and ecological factors accounting for high colonizing ability must be interpreted with caution when the role of longevity, ploidy, interfamily and interpopulation genetic variation, uncertainties about the habitat classification, etc., are taken into account

Subodh Jain

Papers

A model for the estimation of outcrossing rate and gene frequencies using n independent loci

Genetic structure of populations.

Evolutionary divergence among adjacent plant populations I. The evidence and its theoretical analysis

Topics in Plant Population Biology

Are inbreeders better colonizers