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 investigation examines the role of trait-mediated indirect interactions in a simple aquatic food web. We conducted the experiments in cattle watering tanks in order to establish whether competitive and predator-prey interactions between two species are affected by other species in the system; i.e., are pairwise interaction strengths affected by the background species assemblage? We examined the survival and growth response of small bullfrog (Rana catesbeiana) and small green frog (Rana clamitans) tadpoles in the presence and absence of a competitor (large bullfrogs), the lethal presence of the larval odonate predator Tramea lacerata,and the nonlethal (caged) presence of the larval odonate predators Anax junius and Anax longipes. We demonstrate that large bullfrog competitors and caged Anax affect traits (foraging activity level) of small bullfrog and small green frog tadpoles and that these changes in traits, in turn, affect interactions of the small tadpole species with each other and with the other species. In particular, the following four trait- mediated indirect interactions were evident: (1) Presence of large bullfrog competitors increased the predation rate of Trameaon small green frogs and small bullfrogs. (2) Presence of nonlethal Anax reduced the predation rate of Tramea on small green frogs. (3) Presence of nonlethal Anax increased the competitive advantage of bullfrogs over green frogs. (4) Presence of nonlethal Anax facilitated midge invasion of the experimental units. The pro- posed mechanisms (changes in small tadpole activity) involved in these trait-mediated indirect interactions were supported by observational data on tadpole activity and resource levels in the experimental units, and in laboratory experiments examining tadpole activity responses to predators. The occurrence of strong trait-mediated indirect interactions in this simple food web underscores the potential importance of such interactions in animal com- munities.

/pdf/trait-mediated-indirect-interactions-in-a-simple-aquatic-1nxjce6frk.pdf

Trait‐Mediated Indirect Interactions In A Simple Aquatic Food Web

When animals are more active they encounter both more food and more predators. Thus, activity rates mediate a trade-off between growth rates and predation risk. Models of the trade-off generally, but not exclusively, predict reduced activity when re- source availability increases or when predation risk increases. In a laboratory setting, we videotaped larvae of four species of ranid frogs (bullfrog, Rana catesbeiana; green frog, R. clamitans; leopard frog, R. pipiens; and wood frog, R. sylvatica). Changes in activity level in response to changes in food and predator density were measured. Overall, species reduced both the proportion of time active and swimming speed with increases in resource level and predator density. These effects were additive. Regardless of food level, additional predators reduced activity levels similar amounts in all four species. Larger animals, which are less vulnerable to predation, were more active than smaller animals. Leopard frog and wood frog larvae, which are characteristic of more temporary waters, responded more strongly to variation in food levels than did bullfrog and green frog larvae.

/pdf/effect-of-food-and-predators-on-the-activity-of-four-larval-4srncfw0ft.pdf

Effect of food and predators on the activity of four larval ranid frogs

Synopsis. The application of optimal foraging theory to questions of predator behavior, and evidence bearing on the utility of this construct, are reviewed. Experimental tests of simple models predicting prey choice are examined with particular reference to the sizeselection of prey by fish. Laboratory estimates of model parameters are then used to predict prey choice in the field and data from several field tests are presented which corroborate these predictions. When parameters are habitat specific this permits predic? tions of net return from foraging in different habitats and consequendy predictions of habitat use and switching. Field data gathered to test these predictions demonstrate that fish feed in the richer habitats and switch habitats when the profitability of one drops below that of another. Examples are provided showing how these models can then be used to relate behavioral and morphological differences between species and questions at higher levels such as the nature of species interactions and community structure. It is suggested that this may be one of the more useful applications of optimal foraging theory. Finally, some of the criticisms of the theory and important questions requiring further study are discussed.

Optimal foraging: Field tests of diet choice and habitat switching

Because the nature and magnitude of species interactions are functions of the traits that species possess, understanding how individual traits affect performance is important to our understanding of community structure. To examine the relation between species traits and performance, we first assessed behavioral responses of two larval anurans to three predator species in the laboratory. We then correlated these responses with growth performance of the two anurans when they competed in the field. In the laboratory experiment, larval bullfrogs (Rana catesbeiana) and green frogs (R. clamitans) exhibited no reduction in activity or spatial avoidance to bluegill sunfish (Lepomis macrochirus), moderate reductions in activity and spatial avoidance of mudminnows (Umbra limi), and large reductions in activity and spatial avoidance of larval dragonflies (Anax spp.). In the field experiment, these behavioral responses were directly related to corresponding reductions in growth of the anuran larvae. Thus, for both species, changes in growth in the field could be correlated to the behavioral responses observed in the laboratory. Further, proportional changes in behavior in the presence of the different predators appeared to be related to changes in competitive relations in the field.

/pdf/quantifying-the-relation-between-predator-induced-behavior-1abriol71r.pdf

Quantifying the relation between predator-induced behavior and growth performance in larval anurans

The seasonal distributions and abundances of 15 littoral zone fish species were determined from May to October 1976 in a small Michigan lake. A team of divers performed seven censuses along a set of transects which encompassed nearly the entire littoral region of the lake; additional dives enabled us to determine vertical distributions and migration patterns to and from overwintering areas. All species appeared to show less habitat segregation in spring when temperatures rose and food was abundant. Species distributions and abundances were quite constant during the summer and considerable habitat segregation was apparent. The bluegill (Lepomis macrochirus) was the dominant species and was studied in greater detail. Small bluegills (<80 mm total length) were confined throughout the year to the vegetation apparently to avoid predation; larger fish moved up in the water column. This species overwintered in two localized regions of tall perennial vegetation in the deep littoral apparently in response...

Earl E. Werner

Papers

Trait‐Mediated Indirect Interactions In A Simple Aquatic Food Web

Effect of food and predators on the activity of four larval ranid frogs

Optimal foraging: Field tests of diet choice and habitat switching

Quantifying the relation between predator-induced behavior and growth performance in larval anurans

Seasonal distribution and abundance of fishes in the littoral zone of a Michigan lake