[...]... University of British Columbia, 6270 University Blvd., Vancouver, British Columbia, V6T 1Z4 Canada Tatar, Marc Department of Ecology and Evolutionary Biology, Brown University, Box G-W, Providence, Rhode Island 02912 USA Thompson, John N Department of Ecology and Evolutionary Biology, Earth and Marine Sciences Building, University of California, Santa Cruz, California 96064 USA Travis, Joseph Department of... populations is a challenge for evolutionary ecologists, and numerous studies have aimed to do so In many animals, for example, body color is a discrete trait that varies among individuals and affects their vulnerability to their predators For example, the adder, Viperus berus, exhibits two dorsal color patterns: black and zig-zag In a 6-year mark-recapture study of island and mainland pop- Figure 1.1 Examples... color and survivorship is clearly gender-specific, suggesting that the fitness of a given morph depends on the behavior of the individual exhibiting it Individuals of the Lake Erie water snake, Nerodia sipedon insularum, also exhibit qualitative variation in body color pattern (King 1987) Differences in the relative abundances of banded and unbanded morphs between mainland and island populations, and. .. The studies cited in this introduction have by and large considered the evolutionary significance of phenotypic variation within individuals and populations that occupy or are considered to occupy relatively homogeneous environments In the following chapter, we shift the focus to variation among individuals and populations, and we consider the evolutionary consequences of environmental heterogeneity and. .. on the alleles or genotypes at this or other loci (i.e., dominance and epistasis; Mazer and Damuth, chapter 2, this volume) Only in the absence of dominance and epistasis, and where mating is random, can precise predictions be made concerning the similarity between parents and offspring or the phenotypic response to selection Many evolutionary ecologists focus exclusively on the evolution of quantitative... sources (e.g., Reznick and Travis, this volume) In addition, statistical methods have been derived to predict accurately the response to artificial and natural selection on normally distributed traits (Fairbairn and Reeve, this volume) Currently, agriculturalists and evolutionary ecologists alike use these methods both to estimate genetic and environmental causes of phenotypic variance and to predict how... consider the causes and evolutionary consequences of phenotypic variation within individuals Then (in chapter 2), we consider the causes and consequences of variation among individuals in random-mating, unstructured populations, and we describe recent conceptual advances concerning the consequences of population structure In structured populations, genotypes do not interact at random, and the relationship... page intentionally left blank 1 Nature and Causes of Variation SUSAN J MAZER JOHN DAMUTH T causes and consequences of phenotypic variation within and among populations, we can detect evolutionary processes operating at a variety of ecological levels: within random-mating populations; within and among subpopulations distributed over a species' geographic range; and even among multispecies associations... lifetime flower and fruit production, and lifetime maternal fecundity and yield decline, while mean petal area, pollen production, and pollen size remain constant (Mazer and Schick 1991a; Mazer and Wolfe 1998) In animals, the apparent increase in stress that accompanies high population densities often promotes rapid development, as is seen among the larvae of the moth Mamestra brassicae (Goulson and Cory... (Mousseau and Fox 1998) Where there is a nonrandom association between the genotype and the environment of maternal individuals, environmental and genetic maternal influences on offspring phenotype will be confounded Maternal effects often generate phenotypic sim- Evolutionary Significance of Variation ilarities between parents and their offspring that appear to be heritable (e.g., see Reznick and Travis, . class="bi x0 y0 w0 h1" alt="" Evolutionary Ecology This page intentionally left blank Evolutionary Ecology Concepts and Case Studies Edited by CHARLES . relative abundances of banded and unbanded morphs be- tween mainland and island populations, and among young-of-the-year, juvenile, and adult individuals, suggest