Beyond the Adaptationist Legacy: Updating Our Teaching to Include a Diversity of Evolutionary Mechanisms

A paradigm shift away from viewing evolution primarily in terms of adaptation - the adaptationist programme of Gould and Lewontin - began in evolutionary research more than 35 years ago, but that shift has yet to occur within evolutionary education research or within teaching standards. We review three instruments that can help education researchers and educators undertake this paradigm shift. The instruments assess how biology undergraduates understand three evolutionary processes other than natural selection: genetic drift, dominance relationships among allelic pairs, and evolutionary developmental biology (evo-devo). Testing with these instruments reveals that students often explain a diversity of evolutionary mechanisms incorrectly by invoking misconceptions about natural selection. We propose that increasing the emphasis on teaching evolutionary processes other than natural selection could result in a better understanding of natural selection and a better understanding of all evolutionary processes. Finally, we propose two strategies for accomplishing this goal, interleaving natural selection with other evolutionary processes and the development of bridging analogies to describe evolutionary concepts

Many Paths Toward Discovery: A Module for Teaching How Science Works

Improving students\u27 understanding of how science works requires explicit instruction. Here, we test the efficacy of a module based on two previously published activities (the Cube Puzzle and the case study Asteroids and Dinosaurs ) that teach how science works to college science majors. Students also use the How Science Works Flowchart from Understanding Science (http://undsci.berkeley. edu/) to reflect on these activities. To assess the efficacy of this module, we asked students to illustrate the process of science before and after the intervention. After the intervention, students\u27 diagrams were significantly more complex and nonlinear. Students also incorporated more social aspects of science, such as discussing results with colleagues. However, few of the pre- or postdiagrams mentioned the way science benefits society. We conclude that our intervention is an easy-to-implement strategy for improving some aspects of scientific literacy in college students

MICROBIAL ASSOCIATIONS WITH METCALF’S TRYONIA, TRYONIA METCALFI (GASTROPODA: COCHLIOPIDAE), AN IMPERILED CI´ENEGA ENDEMIC

The Chihuahuan Desert swamps are a hotspot for imperiled organisms including freshwater springsnails and bacteria. Many of these taxa are endemic to the desert and to the individual waterbodies where they occur. Efforts to conserve diversity in these threatened areas must account for the life history of the organisms, but also interactions between organisms including microbes. We documented the microbial assemblage associated with Tryonia metcalfi, a critically imperiled freshwater snail endemic to a ciénega system in western Texas. We identified 14 bacterial families in our snail samples and determined a core assemblage of 19 bacterial taxa (4 of which represented novel lineages) that are likely dependent on the snail. Future conservation efforts involving T. metcalfi and its environment should therefore consider the microbial diversity associated with both the snail and the ciénegas. - En las ciénegas del desierto de Chihuahua habitan muchos organismos en peligro, entre ellos caracoles de agua dulce y bacterias. Muchos de estos taxones son endémicos del desierto y de los específicos cuerpos de agua donde ocurren. Esfuerzos para conservar la diversidad en estas áreas amenazadas deben tomar en cuenta la historia de vida de los organismos junto con las interacciones entre ellos, incluyendo microbios. Documentamos el conjunto microbiano relacionado con Tryonia metcalfi, una especie de caracol de agua dulce en peligro de extinción, endémica a un sistema de ciénagas en el oeste de Texas. Identificamos 14 familias bacterianas en nuestras muestras de caracoles y determinamos un conjunto principal de 19 taxones bacterianos; cuatro representan nuevos linajes, que probablemente dependen del caracol. En el futuro, los esfuerzos para proteger a T. metcalfi y su ambiente en consecuencia deben considerarla diversidad microbiana asociada con esta especie de caracol y la ciénega

Mesohabitat Associations Of The Devil Tryonia, Tryonia Diaboli (Gastropoda: Truncatelloidea: Cochliopidae)

The Cochliopidae of Texas include both stygobitic species, those that occupy only underground habitats, and epigean species, those living only in aboveground habitats. The devil tryonia, Tryonia diaboli, was described from the Devils River of Texas from river wrack, without additional habitat information. This species has been largely ignored since its description, so details of its habitat and ecology are obscure. In Dolan Springs and Finegan Springs, flowing into the Devils River, we sampled macroinvertebrates at five sites that form a gradient from the aquifer to the mainstem Devils River. We found the highest abundances of T. diaboli in aquifer samples, decreasing sharply downstream from the spring orifice. Our findings indicate that T. diaboli is stygophilic, occupying a transitional area including the aquifer as well as aboveground portions of springs

Poorly Vetted Conservation Ranks Can Be More Wrong Than Right: Lessons from Texas Land Snails

Setting priorities for scarce conservation dollars requires an accurate accounting of the most vulnerable species. For many invertebrates, lack of taxonomic expertise, low detectability, and funding limitations are impediments to this goal, with conservation ranks usually based on expert opinion, the published literature, and museum records. Because of biases and inaccuracies in these data, they may not provide an accurate basis for conservation ranks, especially when compared to de novo field surveys. We assessed this issue by comparative examination of these data sources in re-ranking the conservation status of all 254 land snail taxa reported from Texas, USA. We confirmed 198 land snail taxa, including 34 new state records. Our assessment of the entire land snail fauna of Texas resulted in (1) a near doubling of recommended Species of Greatest Conservation Need (SGCN) and (2) a 79% turnover in the makeup of SGCN taxa. Field sampling strongly outperformed museum and literature data in the encounter rate of both the entire fauna and all SGCN species, with the latter two demonstrating bias toward larger-bodied species. As a result, conservation priorities based solely on expert opinion and museum and literature records may be more wrong than right, with taxon-appropriate, targeted sampling required to generate accurate rankings

The Dominance Concept Inventory: A Tool for Assessing Undergraduate Student Alternative Conceptions about Dominance in Mendelian and Population Genetics

Despite the impact of genetics on daily life, biology undergraduates understand some key genetics concepts poorly. One concept requiring attention is dominance, which many students understand as a fixed property of an allele or trait and regularly conflate with frequency in a population or selective advantage. We present the Dominance Concept Inventory (DCI), an instrument to gather data on selected alternative conceptions about dominance. During development of the 16-item test, we used expert surveys (n = 12), student interviews (n = 42), and field tests (n = 1763) from introductory and advanced biology undergraduates at public and private, majority- and minority-serving, 2- and 4-yr institutions in the United States. In the final field test across all subject populations (n = 709), item difficulty ranged from 0.08 to 0.84 (0.51 ± 0.049 SEM), while item discrimination ranged from 0.11 to 0.82 (0.50 ± 0.048 SEM). Internal reliability (Cronbach\u27s alpha) was 0.77, while test–retest reliability values were 0.74 (product moment correlation) and 0.77 (intraclass correlation). The prevalence of alternative conceptions in the field tests shows that introductory and advanced students retain confusion about dominance after instruction. All measures support the DCI as a useful instrument for measuring undergraduate biology student understanding and alternative conceptions about dominance

Assessing infection patterns in Chinese mystery snails from Wisconsin, USA using field and laboratory approaches

The success of invasive species establishment in new habitats depends, in part, on interactions with other members of the invaded community. Cipangopaludina chinensis, the Chinese mystery snail (CMS), is an exotic, invasive snail in North America. Since its introduction in the 1890s, CMS have spread to a number of watersheds across the United States and parts of Canada. This invasion has generated questions about the snail’s capacity to serve as a host for parasites within local habitats, including parasites with conservation implications. To begin addressing these questions, we necropsied 147 wild-caught snails from 22 lakes across Wisconsin, finding only two CMS individuals harboring trematode (flatworm) parasites. We also conducted experimental exposures using a trematode (Sphaeridiotrema pseudoglobulus) implicated in waterfowl die-offs and found that CMS infection levels were significantly lower than those in co-occurring snail species. Furthermore, the parasites that did successfully infect CMS were often found encased in the shells of the snails in a non-viable state. Together these results 1) provide insight into the importance of CMS as a host for parasites in the region, and 2) may help to explain the wide distribution of CMS across WI and the Midwest

Resaca supports range expansion of invasive apple snails (Pomacea maculata Perry, 1810; Caenogastropoda: Ampullariidae) to the Rio Grande Valley, Texas

Resacas, or oxbow lakes, form from old river channels. In the Rio Grande, resacas provide habitat for diverse wildlife, including native and non-native species. Biologists unexpectedly found pink egg masses on emergent vegetation (November 2015) and later adult apple snails (May 2016) within a resaca at a former fish hatchery in Brownsville, Texas. This report extends the non-native range of Pomacea maculata Perry, 1810 by 429 km southeast in Texas. Our findings imply that abandoned waterbodies, such as fish hatcheries, can act as unrecognized conduits for non-native invasive species

Relationship between stream velocity & depth and snail size distribution & density of the balcones elimia, elimia comalensis (pilsbry, 1890) (gastropoda: pleuroceridae) in comal springs, texas

Pleurocerid snails are important components of aquatic ecosystems and the majority of species are threatened or endangered. This study describes aspects of the life-history of Elimia comalensis, specifically population density in relationship to water velocity and depth, and seasonal change. Also examined are spatial segregation of different E. comalensis age groups and the relationship of snail size (proxy for age) to flow, depth, and seasonal change. The study was carried out in the lotic portion of spring run 3, Comal Springs, New Braunfels, Texas, by quadrat sampling at 10 m intervals from the spring head to Landa Lake in Fall, Winter, and Spring 2005-2006. The length of snails was strongly influenced by physical characteristics of the stream with stream depth, water velocity, and distance from the spring head accounting for -43% of the individual variability for shell length (