Abstract. Isolation by distance (IBD) models are widely used to predict levels of genetic connectivity as a function of Euclidean distance, and although recent studies have used GISlandscape ecological approaches to improve the predictability of spatial genetic structure, few if any have addressed the effect of habitat continuity on gene flow. Landscape effects on genetic connectivity are even less understood in marine populations, where habitat mapping is particularly challenging. In this study, we model spatial genetic structure of a habitatstructuring species, the giant kelp Macrocystis pyrifera, using highly variable microsatellite markers. GIS mapping was used to characterize habitat continuity and distance between sampling sites along the mainland coast of the Santa Barbara Channel, and their roles as predictors of genetic differentiation were evaluated. Mean dispersal distance (r) and effective population size (N e ) were estimated by comparing our IBD slope with those from simulations incorporating habitat continuity and spore dispersal characteristics of the study area. We found an allelic richness of 7-50 alleles/locus, which to our knowledge is the highest reported for macroalgae. The best regression model relating genetic distance to habitat variables included both geographic distance and habitat continuity, which were respectively, positively and negatively related to genetic distance. Our results provide strong support for a dependence of gene flow on both distance and habitat continuity and elucidate the combination of N e and r that explained genetic differentiation.
Postelsia palmaeformis (Ruprecht) is an intertidal brown alga belonging to the ecologically and economically important group of seaweeds commonly referred to as kelp (Order Laminariales). Six polymorphic microsatellite loci were identified for this monotypic genus. The number of alleles ranged from two to five, with observed heterozygosities ranging from 0.00 to 0.704.
This study characterized morphological variation in the kelp, Egregia menziesii, over a large geographic scale. Marked differences in rachis and lateral blade morphology were observed, suggesting local adaptation to the variable conditions of wave exposure and upwelling found across the study area. Observations of rachis type at different developmental stages indicated differential survivorship of smooth versus papillated individuals at sites with differing wave exposure. Variations in Egregia morphology have long been recognized and were previously used for discriminating species within the genus; thus, we tested the hypothesis that the different morphological forms reflect genetically distinct populations. Nucleotide sequences of the ITS regions did not reveal genetic structure among three, morphologically distinct populations providing little evidence for speciation in Egregia.
This paper describes and evaluates a major renovation of a human anatomy and physiology lab for allied health students. A Howard Hughes Medical Institute award funded an extensive collaboration between faculty involved in teaching the course and faculty with expertise in industrial and furniture design. The resulting physical lab has unique features designed to improve work in groups, student movement, and integration of computers with wet laboratories. The anatomy curriculum was switched from fetal pig dissections to the use of human cadavers, computer animations, and plastic models. An inquiry approach was integrated into the physiology curriculum. Student attitude surveys suggest that the physical and curricular changes resulted in a significant increase in student learning. An experiment designed to specifically test the effect of new vs. old equipment did not support a benefit to new equipment independent of changes in the lab physical environment and curriculum. Because the improvements in student attitude surveys occurred in the physiology but not the anatomy labs, we suggest that at least a portion of the increase is due to the institution of the inquiry approach.
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