Rob Wass

Scaffolding Critical Thinking in the Zone of Proximal Development.

This paper explores student experiences of learning to think critically. Twenty‐six zoology undergraduates took part in the study for three years of their degree at the University of Otago, New Zealand. Vygotsky’s developmental model of the Zone of Proximal Development (ZPD) provided a framework as we examined how critical thinking was developed. There was very little evidence of critical thinking at first year as students experienced a high‐level of material scaffold in the form of course documents, textbooks, problem solving‐exercises and discussions that were primarily aimed at the acquisition of factual knowledge. In large classes students were anonymous to lecturers and they relied on each other for support. In years 2 and 3, learning to do research became the main scaffold for critical thinking and students gradually changed their views about the nature of knowledge. Verbal scaffolding and conversation with lecturers and peers allowed students to extend their ZPD for critical thinking. They began to accept responsibility for their own and their peers’ learning as they practiced being a zoology researcher. These findings are discussed in relation to two approaches to scaffolding in the ZPD and it is suggested that research should be an integral part of the first year if critical thinking remains a key aim for higher education.

Changes in steroid hormone profiles and ovarian histology during salmon pituitary-induced vitellogenesis and ovulation in female New Zealand longfinned eels, Anguilla dieffenbachii gray

To assess whether induced vitellogenesis in longfinned eels mimics that in naturally maturing conspecifics, female eels were artificially matured and steroid hormone status and oocyte cytology during oogenesis were evaluated. Successful induction of vitellogenesis was evident from the presence of yolk granules in the ooplasm of salmon pituitary homogenate (SPH)-injected, but not saline-, 17-hydroxyprogesterone-, and/or gonadotropin-releasing hormone-treated fish. In SPH-treated females, the migratory nucleus stage was reached after 33-53 days, followed by ovulation around 30 hours after induction of final maturation and ovulation. Only a portion of the germ cells matured, although resumption of vitellogenesis was seen in the majority of oocytes. In contrast, in ovaries of saline-injected controls, the most advanced oocytes were early vitellogenic. Atretic follicles were observed in ovaries of all eels, but abundance was greater in controls than in SPH-treated fish. SPH injections elevated plasma levels of estradiol-17beta and androgens, but not pregnenes, from within three days of treatment. Our results indicate that sex steroid levels in midvitellogenic hormone-treated females are similar to those in wild midvitellogenic females. In contrast, differences in yolk morphology of midvitellogenic follicles were seen between SPH-treated and wild females, especially in the second crop of midvitellogenic-sized oocytes measuring 300-400 microm in diameter. We discuss whether the observed differences affect egg quality, and perhaps explain the short life span of captive-bred eel larvae. J. Exp. Zool. 289:119-129, 2001.

Sharpening a tool for teaching: the zone of proximal development

Vygotskys Zone of Proximal Development (ZPD) provides an important understanding of learning, but its implications for teachers are often unclear or limited and could be further explored. We use conceptual analysis to sharpen the ZPD as a teaching tool, illustrated with examples from teaching critical thinking in zoology. Our conclusions are the following: teachers should assign tasks that students cannot do on their own, but which they can do with assistance; they should provide just enough assistance so that students learn to complete the tasks independently and, finally, teachers can increase learning gains by providing learning environments that enable students to do harder tasks than would otherwise be possible and by assigning the hardest tasks students can do with assistance. This analysis provides a sharp and useful tool for supporting learning across all curriculum areas.

Grazing by black swans (Cygnus atratus Latham), physical factors, and the growth and loss of aquatic vegetation in a shallow lake

Abstract Hawksbury Lagoon, a shallow coastal New Zealand lake, alternates between a clear-water, macrophyte-dominated state, and a turbid, phytoplankton-dominated state. The potential role of black swans ( Cygnus atratus Latham) in stabilising the phytoplankton dominated state by grazing on macrophytes was investigated during a period of increase and decline in the benthic vegetation ( Nitella ) in 1993–1994. The swan population density was closely correlated with plant biomass ( r 2 = 0.95). Although the swan population became as high as 25 ha −1 direct grazing consumption was slight. The grazing rate was 0.007 day −1 , by comparison with plant growth rates of 0.06–0.10 day −1 , and loss rates in periods of decline of 0.07–0.18 day −1 . Indirect effects of the swans on the plants through nutrient recycling and bioturbation, are also unlikely to have been important. Concentrations of suspended solids and phytoplankton, and light attenuation, remained high throughout the study. Plant biomass normally increased when the benthic photon irradiance exceeded 7% of that at the surface, and decreased when it was lower than that. We conclude that lack of light was far more important than swan grazing for plant decline. When light or other conditions for macrophyte growth are marginal, the cumulative effect of waterfowl grazing consumption might well be critical, however, for keeping macrophyte biomass below the threshold for macrophyte dominance, in spite of the consumption being small.

An assessment arms race and its fallout: high-stakes grading and the case for slow scholarship

This research questions the impact of assessment on university teaching and learning in circumstances where all student work is graded. Sixty-two students and lecturers were interviewed to explore their experiences of assessment at an institution that had adopted a modular course structure and largely unregulated numbers of internal assessments. Lecturers rewarded student work with grades and controlled study behaviour with assessment. In some situations it was possible to experience hundreds of graded assessments in an academic year. Students were single-minded when it came to grades and would not work without them. These conditions contributed to competition for student attention and a grading arms race between academics and subjects. In this context, the spaces for achieving certain educational objectives, such as fostering self-motivated learners, were marginalised. Both students and lecturers were unsatisfied with this situation, but neither group could envisage radical change. Students were generally happy to accumulate small marks, while being irritated and stressed by frequent grading. Lecturers were aware of better practices but felt trapped by circumstances. The idea of slow scholarship is introduced to encourage a re-think of such assessment practices, support a positive shift in assessment culture and contribute to the theories of assessment.

Food consumption and faecal deposition of plant nutrients by black swans (Cygnus atratus Latham) in a shallow New Zealand lake

Deposition of faeces by black swans (Cygnus atratus Latham) feeding on benthic algae in a shallow New Zealand lake was determined by collection of faeces from the lake bottom and from the shore. The two methods showed good agreement after adjustment for the weight loss on immersion. The mean daily faecal output per swan was 52 g dry weight. The nitrogen content of the faeces averaged 2.3% of dry weight, and was dominated by soluble organic nitrogen (59% of total N). Phosphorus averaged 0.44% of dry weight, with 66% of it being particulate, and 30% soluble reactive phosphorus. Although faecal inputs of total phosphorus were sufficient to generate concentrations of 15–30 mg m−3, the faecal contributions of both N and P were only a minor component of the fluctuations observed in the lake, and were also small in relation to the total nutrient pool in the water and benthic algae. Waterfowl faeces appear to have low ratios of N to P, which will favour dominance of the phytoplankton by cyanobacteria in lakes where the faecal component of nutrient loads is large. The few data available suggest that the nitrogen content of waterfowl faeces is largely independent of that in their food. Food consumption, calculated by using cellulose as an indigestible faecal marker, was 104 g dry weight swan−1 d−1, a figure that appears low in relation to those for other swan species. Even the highest published figure for food intake by a swan is only about one half of the corresponding average metabolically-adjusted figures for geese, and we caution against the uncritical use of bioenergetic models for determining rates of food consumption and defaecation.

What Do Herbivore Exclusion Experiments Tell Us? An Investigation Using Black Swans (Cygnus atratus) and Filamentous Algae in a Shallow Lake

One common approach to the problems of quantifying herbivory is to determine how much plant material herbivores eat. Another is to exclude the herbivores experimentally and compare the performances of the grazed and ungrazed plant communities. Both approaches may give biased estimates of the interaction strength or effect of grazers on plant biomass increase or productivity (Mitchell and Wass, 1996a). Simple consideration of the fraction of annual plant productivity consumed ignores the effect of the time at which the material is consumed. Because grazing removes not only biomass but also the future productive potential of that biomass, consumption of small amounts of plant tissue early in a plant growth cycle has a greater effect than similar amounts of consumption later (e.g., Kiorboe, 1980). It also neglects the indirect feedback effects of herbivores, such as nutrient recycling, damage to the plants, or relief of density suppression of growth (e.g., Lodge, 1991).

Negotiating the challenge of collaborative writing: learning from one writing group's mutiny

With continuing pressure to publish or perish, interventions such as writing groups are increasingly part of the academic landscape. In this paper, we discuss our writing groups experiment with collaborative writing, which came unstuck as simmering concerns led to a mutiny within the group. The mutiny provided insights into tensions that are inevitably present in writing groups and collaborative writing exercises but are seldom written about. We explore these tensions via a collaborative autoethnography, drawing on published literature on writing groups and collaborative writing. The mutiny revealed three key dynamics. Experienced voices can have an important role to play but these voices need to be moderated so that other voices might be recognised and valued. Pleasure and productivity are two necessary components for sustaining writing groups and writing collaborations. Finally, hierarchies in the academic context are inescapable but they can be renegotiated so that more enabling power relations can be generated.

‘Will press lever for food’: behavioural conditioning of students through frequent high-stakes assessment

This piece offers some challenging ideas about using assessment in the behavioural conditioning of students in higher education. Recently, we conducted a research project that looked at the impacts of continuous, high stakes assessment at a New Zealand university (Harland, McLean, Wass, Miller, & Sim, 2014). We found that students were assessed so frequently that all their learning was done for a grade and if there were no grade involved, then they would not study. Students had a love–hate relationship with grading: they were not keen to have exams that were worth 100% and acknowledged that frequent small assessments were useful for keeping them on track. However, at the same time, they felt stressed by being continually assessed. Lecturers recognised this set of circumstances, but to compete for student time, had to set grades for all work. This state of affairs resulted in an assessment arms race between lecturers who controlled student study behaviour with grading. We considered such practices to impact negatively on the development of autonomous, self-directed and life-long learners. In essence, the culture of assessment we observed seemed to produce compliant students who expected a reward for all effort. Are these the sort of attributes that reflect a higher education, or the outcomes society expects in return for its investment in our university system?

Entry Characteristics and Participation in a Peer Learning Program as Predictors of First-Year Students’ Achievement, Retention, and Degree Completion:

Success in the first year of higher education is important for students’ retention beyond their first year and for completion of their undergraduate degree. Institutions therefore typically front-load resources and interventions in the first year. One such intervention is the Peer Assisted Study Sessions (PASS) program. This program is known in the United States as Supplemental Instruction. It provides first-year students with an opportunity to learn study skills in the context of a particular unit of study (course/module). In this article, we consider the relationship between students’ prior academic achievement and participation in the PASS program, as well as the impact of participation on first-year students’ first-year grade point average, retention, and degree completion. The findings suggest that PASS does not just attract academically high-achieving students and that participation in it contributes to students’ academic achievement in their first year, retention beyond the first year, and completion of an undergraduate degree.