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

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

Pseudoreplication is defined. as the use of inferential statistics to test for treatment effects with data from experiments where either treatments are not replicated (though samples may be) or replicates are not statistically independent. In ANOVA terminology, it is the testing for treatment effects with an error term inappropriate to the hypothesis being considered. Scrutiny of 176 experi- mental studies published between 1960 and the present revealed that pseudoreplication occurred in 27% of them, or 48% of all such studies that applied inferential statistics. The incidence of pseudo- replication is especially high in studies of marine benthos and small mammals. The critical features of controlled experimentation are reviewed. Nondemonic intrusion is defined as the impingement of chance events on an experiment in progress. As a safeguard against both it and preexisting gradients, interspersion of treatments is argued to be an obligatory feature of good design. Especially in small experiments, adequate interspersion can sometimes be assured only by dispensing with strict random- ization procedures. Comprehension of this conflict between interspersion and randomization is aided by distinguishing pre-layout (or conventional) and layout-specifit alpha (probability of type I error). Suggestions are offered to statisticians and editors of ecological j oumals as to how ecologists' under- standing of experimental design and statistics might be improved.

/pdf/pseudoreplication-and-the-design-of-ecological-field-44o8kzdaoi.pdf

Pseudoreplication and the Design of Ecological Field Experiments

Predation has long been implicated as a major selective force in the evolution of several morphological and behavioral characteristics of animals. The importance of predation during evolutionary ti...

Behavioral decisions made under the risk of predation: a review and prospectus

http://osenberglab.ecology.uga.edu/wp-content/uploads/2015/09/Charnov-1976-TPB.pdf

Optimal foraging, the marginal value theorem.

This study integrates laboratory and field results to interpret habitat use and switching by individual bluegill sunfish (Lepomis macrochirus). Prey handling and search times for the bluegill were determined from laboratory feeding experiments at different prey sizes and densities in open water and sediment habitats. Relationships were then constructed to predict the expected return per unit time foraging in these habitats. Experience (learning) was found to increase foraging efficiency up to fourfold over the course of six to eight foraging bouts. A population of 225 bluegills was then introduced into a pond consisting predominantly of open water and sediment habitats. This population exhibited several habitat switches as resources declined during the 3-mo experiment; in addition, the population split over a 5-wk period, with individuals specializing on one habitat or the other. These specialists were considerably more successful than habitat generalists as measured by average amount of food in the stomachs. Return rates estimated from the laboratory experiments indicated that the two habitats were nearly equal in foraging profitability. The individual specialization indicated that learning and mutually interfering foraging mechanisms were involved in the species' use of the two habitats. The results suggest that learning and sampling are important aspects of both habitat use and the specialization of individuals within a population.

https://www.jstor.org/stable/pdfplus/1936675.pdf

The Role of Foraging Profitability and Experience in Habitat Use by the Bluegill Sunfish

This study examines the influence of forest canopy cover on the breeding pond distributions of wood frogs (Rana sylvatica), leopard frogs (R pipiens), and American toads (Bufo americanus). Survey results indicated that wood frogs bred in both openand closed-canopy ponds, whereas leopard frogs and toads did not. We conducted two experiments in 1.5-m2 cages set in natural ponds to evaluate species' performance in open- and closed-canopy ponds. The first experiment was conducted in two open-canopy and two closed-canopy ponds and demonstrated that tadpole growth and survivorship for all three species were higher in open-canopy ponds. Wood frogs, however, also grew and survived well in closed-canopy ponds, whereas performance of leopard frogs and toads was very poor in closed-canopy ponds. Competition between species was asymmetrical; wood frogs affected leopard frogs, but the reverse effect was negligible. The second experiment was conducted in the two closed-canopy ponds with wood frogs and leopard frogs and indicated that food supplementation dramatically increased both survivorship and growth rate of leopard frogs. There was no effect of food addition on wood frog survivorship and a minimal effect on growth rate. Resource differences between open- and closedcanopy ponds therefore appear to have a strong influence on distributions of these species. Dissolved oxygen concentrations also were lower in closed- than in open

Influence of Forest Canopy Cover on the Breeding Pond Distributions of Several Amphibian Species

Models suggest that phenotypic plasticity is maintained in situations where the optimal phenotype differs through time or space, so that selection acts in different directions in different environments. Some empirical work supports the general premise of this prediction because phenotypes induced by a particular environment sometimes perform better than other phenotypes when tested in that environment. We have extended these results by estimating the targets of selection in Pseudacris triseriata tadpoles in environments without predators and with larval Anax dragonflies. Tadpoles displayed significant behavioral and morphological plasticity when reared in the presence and absence of nonlethal dragonflies for 32 days in cattle tanks. We measured selection in the absence of free predators by regressing growth and survival in the tanks against activity and several measures of tail and body shape. We measured selection in the presence of predators by exposing groups of 10 tadpoles to Anax in overnight predation trials and regressing the average phenotype of survivors against the number of tadpoles killed. Selection in the two environments acted in opposite directions on both tail and body shape, although the affected fitness components were different. In the presence of Anax, tadpoles with shallow and narrow body, deep tail fin, and wide tail muscle survived best. In the absence of free predators, tadpoles with narrow tail muscle grew significantly faster, and those with shallow tail fin and deep body grew somewhat faster. Activity was unrelated to survival or growth in either environment. Developmental plasticity in tail shape closely paralleled selection, because tail fin depth increased after long-term exposure to Anax and tail muscle width tended to increase. In contrast, there was no plasticity in body shape in spite of strong selection for decreasing body depth. Thus, when confronted with a dragonfly predator, P. triseriata tadpoles adjusted their tail shape (but not body shape) almost exactly in the direction of selection imposed by Anax. These results suggest that phenotypic plasticity in some morphological traits, such as tail depth and tail muscle width, has evolved under intermittent selection by dragonflies. Other traits that undergo selection by dragonflies, such as body morphology, appear developmentally rigid, perhaps because of historically strong opposing selection in nature or other constraints.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1558-5646.1997.tb05119.x

Natural selection for environmentally induced phenotypes in tadpoles.

I examine the nonlethal effects of a predator, an odonate larva (Anaxjunius), on competitive interactions between two species of anuran larvae (bullfrog, Rana cates- beiana, and green frog, R. clamitans). The anurans coexist in permanent ponds, which sometimes contain high densities of A. junius. Laboratory experiments indicated that in the absence of the predator, the two species were similar in competitive abilities and grew at virtually identical rates. In the presence of caged A. junius, however, the bullfrog grew to be larger and the green frog much smaller than when the predator was absent. Both species reacted to the presence of A. junius by reducing activity and altering space use. I argue that the reductions in activity in the presence of the predator affected the two species differently, which in turn changed competitive interactions. I discuss the relation between activity level and competitive ability, and the potential for predators to alter competitive relations by affecting activity levels of syntopic species (a higher order interaction). Vul- nerability to predators also increases with activity, and I discuss the implications of an activity-mediated trade-off between growth rate and predation risk to interactions among anuran larvae. Finally, I present a method for quantitatively evaluating the net balance of (negative) direct mortality effects and (sometimes positive) indirect effects that alter com- petitive ability.

Nonlethal Effects of a Predator on Competitive Interactions Between Two Anuran Larvae

In this article I address the manner in which ecological and developmental factors shape behaviors and the consequences of these behaviors to species interactions. An important potential consequence of adaptive behavioral responses is higher-order interactions among species (e.g., in which the presence of a third species qualitatively alters the nature of the interaction between two other species). To illustrate this potential, I examine two broad classes of adaptive behavioral responses, choice of activity level and of habitat. I review evidence that suggests that in many organisms these behaviors are mediated by trade-offs between resource acquisition and mortality risk. This trade-off provides a conceptual foundation on which to predict individual behavior, and since the trade-off changes with size, marked behavioral allometries may occur over an individual's ontogeny. I present evidence that these sorts of behavioral responses create strong higher-order interactions. I argue that theory at the individ...

Earl E. Werner

Papers

The Role of Foraging Profitability and Experience in Habitat Use by the Bluegill Sunfish

Influence of Forest Canopy Cover on the Breeding Pond Distributions of Several Amphibian Species

Natural selection for environmentally induced phenotypes in tadpoles.

Nonlethal Effects of a Predator on Competitive Interactions Between Two Anuran Larvae

Individual behavior and higher-order species interactions