Teaching the process of science with primary literature: Using the CREATE pedagogy in ecological courses.

There have been numerous calls for improved pedagogical practices in biological education, and there is a clear need for such improvements in ecology and related curricula. Most ecology-related texts lack pedagogy and are designed to be content-rich. National initiatives, such as Vision & Change, provide guidance on undergraduate biology education, including increasing use of evidence-based active learning, and taking a more conceptual and science practice skills approach. Biology education research is rich with evidence-based teaching practices, which reveal that active learning approaches implemented in thoughtful ways lead to strong learning gains relative to lecture-based course delivery. CREATE (Consider, Read, Elucidate the hypothesis, Analyze and interpret data, Think of the next Experiment) integrates evidence-based active pedagogical practices into one approach to STEM education that focuses heavily on the process of science and science practice skills rather than content delivery by replacing the textbook with selected journal articles. The approach focuses on deep reading and analysis of primary literature; immersing students in the literature is an advantage of the pedagogy. CREATE was developed and tested in other biological disciplines (genetics and molecular biology) that have long been at the forefront of pedagogical best practices in biology. We transformed two upper-level undergraduate ecological courses (Conservation Biology, and Biodiversity and Ecology) into CREATE courses. We provide examples of assignments, student work, and assessments of the approach, illustrating the various ways CREATE can be successfully implemented. The approach can be adopted in part, to ease into it and test it out, or in whole. We recommend that ecology teachers consider making their courses more active, if they have not already done so; adopting pedagogical practices embedded within CREATE can be a way to achieve active learning. The CREATE approach and other evidence-based pedagogical best practices lead to strong learning gains and more inclusive learning environments.

Encouragement for Faculty to Implement Vision and Change.

The seminal report Vision and Change outlined improvements necessary for undergraduate biology courses to accomplish widely recognized learning objectives. Over the past 8 years, we have developed a two-semester introductory biology course that incorporates the core concepts and competencies recommended in Vision and Change Using published research on how students learn, we focused our efforts on three main areas of change: pedagogy, course content, and technology. We introduced active-learning strategies to improve our classroom environments, wrote an e-textbook that provides students with the tools they need to construct their own knowledge, and employed an online learning hub to assist students who needed extra support. The redesigned courses have been well received by students, and we have seen good student learning outcomes. The purpose of this essay is to demonstrate to faculty that Vision and Change's recommendations are feasible and students welcome the improvements.

Implementing recommendations for introductory biology by writing a new textbook.

We redesigned the undergraduate introductory biology course by writing a new textbook (Integrating Concepts in Biology [ICB]) that follows first principles of learning. Our approach emphasizes primary data interpretation and the utility of mathematics in biology, while de-emphasizing memorization. This redesign divides biology into five big ideas (information, evolution, cells, emergent properties, homeostasis), addressing each at five levels of organization (molecules, cells, organisms, populations, ecological systems). We compared our course outcomes with two sections that used a traditional textbook and were taught by different instructors. On data interpretation assessments administered periodically during the semester, our students performed better than students in the traditional sections (p = 0.046) and exhibited greater improvement over the course of the semester (p = 0.015). On factual content assessments, our students performed similarly to students in the other sections (p = 0.737). Pre- and postsemester assessment of disciplinary perceptions and self-appraisal indicate that our students acquired a more accurate perception of biology as a discipline and may have developed a more realistic evaluation of their scientific abilities than did the control students (p < 0.05). We conclude that ICB improves critical thinking, metacognition, and disciplinary perceptions without compromising content knowledge in introductory biology.

Local and regional factors influence the structure of treehole metacommunities.

BACKGROUND: Abiotic and biotic factors in a local habitat may strongly impact the community residing within, but spatially structured metacommunities are also influenced by regional factors such as immigration and colonization. We used three years of monthly treehole census data to evaluate the relative influence of local and regional factors on our study system. RESULTS: Every species responded to at least one of three local environmental factors measured: water volume, leaf litter mass, and presence of a top predator. Several species were affected by water volume, and a non-exclusive group of species were influenced by leaf litter mass. Relative abundance of Aedes triseriatus was higher in treeholes with higher volumes of water, and relative abundances of three out of six other species were lower in treeholes with higher volumes of water. Leaf litter mass positively affected densities of Aedes triseriatus and relative abundance of several dipteran species. The density of the top predator, Toxorhynchites rutilus, affected the relative abundance of the two most common species, A. triseriatus and Culicoides guttipennis. Treeholes with T. rutilus had an average of two more species than treeholes without T. rutilus. We found little evidence of synchrony between pairs of treeholes, either spatially or temporally. There were high levels of spatial and temporal turnover, and spatial turnover increased with distance between patches. CONCLUSION: The strong effects of water volume, leaf litter mass, and presence of a top predator, along with the high temporal turnover strongly suggest that species presence and density are determined by local factors and changes in those factors over time. Both low water volume and high predator densities can eliminate populations in local patches, and those populations can recolonize patches when rain refills or predators exit treeholes. Population densities of the same species were not matched between pairs of treeholes, suggesting variation in local factors and limited dispersal. Distance effects on spatial turnover also support limitations to dispersal in the metacommunity, and we conclude that the weight of evidence favors a strong influence of local factors relative to regional factors.

Decaying invertebrate carcasses increase growth of Aedes triseriatus (Diptera: Culicidae) when leaf litter resources are limiting.

Treeholes are detritus-based communities, and resource quantity and quality play a large role in structuring such communities. The primary resource is leaf litter, but decaying invertebrates also are a resource to treehole inhabitants. These communities are subject to a variety of disturbances, which may affect resources or cause widespread mortality. When dead inhabitants decay, they provide a potentially high-quality resource to survivors or subsequent colonists. We predicted that variation in decaying larvae (0, 7.3, and 29.2 mg/liter) and leaf litter (1, 5, and 10 g/liter) would influence the performance of populations of Aedes triseriatus (Say), the eastern treehole mosquito. We tested this prediction in field mesocosms, which were subjected to a freezing event causing widespread mortality of the scirtid beetle Helodes pulchella Guerin. We then added a cohort of first instar mosquitoes to mesocosms, and we monitored their development from March until June 2005. At the highest leaf litter level, survival, adult mass, and time to complete development were unaffected by decaying scirtids, and they were different from treatments with lower levels of leaf litter. In treatments with 1 and 5 g/liter leaf litter and decaying scirtids, mosquito survival and adult mass were higher than in treatments with 1 and 5 g/liter leaf litter and no decaying scirtids. At 5 g/liter leaf litter, a higher mass of dead scirtids was required to significantly increase adult mass. Faster decay of carcasses and release of limiting nutrients likely spur growth of microorganisms, upon which mosquitoes feed. Invertebrate populations in high-disturbance communities may be subject to high mortality, and mosquitoes hatching after the disturbance will benefit, but only when other resources are limiting.

The pesticide malathion reduces survival and growth in developing zebrafish.

Malathion is an organophosphorous pesticide widely used to control mosquitoes in urban areas and pests, such as boll weevils, in agricultural areas. Zebrafish, Danio rerio, are model organisms for developmental toxicology research because they are readily available, produce large numbers of clear embryos, and are sensitive to environmental changes. The nonlethal effects of malathion on developing zebrafish embryos, however, previously have not been analyzed quantitatively. We exposed zebrafish embryos to sublethal malathion concentrations to determine malathion's effects on a developing vertebrate. Zebrafish exposed to 0.5, 1.0, or 1.5 mg/L of malathion consistently elicited more rapid hatching from the chorion than zebrafish exposed to 2.0-, 2.5-, or 3.0-mg/L malathion concentrations. In addition, exposure to 2.0, 2.5, or 3.0 mg/L of malathion resulted in significantly shorter body length and eye diameters, indicating that malathion had teratogenic effects on zebrafish embryos. Malathion's action as an acetylcholinesterase inhibitor and the toxicity of the metabolites of malathion may be responsible for malathion's teratogenic effects on fish development.