Browsing by Author "Brown, Kelly Joanne."

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Seasonal variation in the thermal biology of the rock hyrax (Procavia capensis)
(2003) Brown, Kelly Joanne.; Downs, Colleen Thelma.
Animals in the Southern African sub-region are faced with unpredictable seasonal rainfall patterns and unpredictably low resource availability due to the influence of the El Nino Southern Oscillation System. This has led to conservative energetic traits in animals that offset the costs of maintaining homeostasis in the unpredictable environments they inhabit. One of these animals is the rock hyrax (Procavia capensis). Past research has looked at the thermoregulation of rock hyrax in the laboratory. Results indicated that rock hyrax had labile body temperatures that reached lethal levels at ambient temperatures above 39°C. Laboratory studies separate endogenous thermoregulation from behavioural thermoregulation and do not reflect the overall thermoregulatory potential of the rock hyrax in maintaining body temperatures. This study looked at the thermoregulation of rock hyrax in their natural environment. Body temperatures were measured in the field using Thermochron iButtons inserted into the intraperitonial cavity of the animals. Behavioural observations were also recorded on subgroups and individually marked animals. Rock hyraxes were exposed to large fluctuations in ambient temperatures and food availability during the course of this study. In winter, ambient temperatures ranged between 5-25°C and in summer between 18-42°C. Our results show that rock hyrax seasonally and daily altered both their physiological and behavioural thermoregulation to control body temperature efficiently. The physiological alterations observed in rock hyrax differed between winter and summer. During winter, when food availability was low, rock hyrax maintained body temperatures at a lowered level relative to summer. Body temperatures fluctuated to a greater extent during winter as a result of reduced body temperatures at night and increased body temperatures due to basking during the diurnal hours. During summer, rock hyrax displayed high body temperatures, which reached hyperthermic levels. This enabled rock hyrax to forage during midday hours since heat loads could be easily dissipated through passive conduction in the cooler rock crevices. Rock hyrax employed different behavioural patterns in winter and summer. It is proposed that rock hyraxes are unable to meet energetic demands on a low quality and patchy food resource under low ambient temperatures. Predation is also a cost to foraging and becomes increasingly important when rock hyraxes have to move large distances away from crevices to find food. The most frequent behaviour recorded in rock hyrax during winter was basking. Basking enabled rock hyrax to maintain body temperatures with very little thermoregulatory cost. Differences were also recorded in behavioural patterns in rock hyrax of different sizes. Juveniles, due to their small body size and high energetic demands foraged more frequently than adult rock hyrax. During summer, rock hyrax spent considerable time in the rock crevices. This was because ambient temperatures exceeded the upper limit of the thermoneutral zone of the rock hyrax throughout most of the day. Rock hyrax therefore escaped the excessive temperatures by utilizing the cooler rock crevices, which remained at temperatures within the rock hyraxes thermoneutral zone. The most frequent behaviour recorded in rock hyrax aboveground was foraging. Since forage was abundant around the rock crevices during summer, predation risk was less of a factor influencing foraging behaviour. Since basking is an essential component of the rock hyraxes thermal biology during winter we examined basking behaviour in more detail. Basking in the morning was not used to increase body temperatures from hypothermic levels as otherwise thought. Instead, it was used to maintain body temperatures at low ambient temperatures by altering posture, orientation to the sun and basking bout lengths. During the early morning, when heating rates were greatest, rock hyrax orientated their bodies exposing the greatest surface area to solar radiation. During midday, reduced basking bout lengths and the reduction of surface areas exposed to the sun reduced the heat loads during the hottest parts of the day. Rock hyrax appeared to utilize the warm rock surfaces during the late afternoon when the sun was setting to maintain body temperatures before entering the crevices for the night. The combination of physiological and behavioural thermoregulation therefore enables rock hyrax to maintain homeostasis with very little energetic costs in an environment that displays variability in both ambient temperatures and resource availability.
Students' competence and understanding of scientific method in the life sciences at the University of KwaZulu-Natal.
(2015) Brown, Kelly Joanne.; Downs, Colleen Thelma.
This thesis focuses on describing the conceptions and misconceptions that undergraduate Life Science students hold regarding aspects of the scientific method at the University of KwaZulu-Natal (UKZN). This research is necessary in order that instruction strategies can be formulated and implemented to address these misconceptions, in response to a global call to redefine how science is taught at tertiary level. The University of KwaZulu-Natal is located over a number of campuses with courses and curricula material being taught across campuses by different faculty staff. The apparent role that faculty staffs’ epistemologies, instructional strategies and assessment tools may perform in influencing students’ conceptions of scientific method led us to concentrate on some of these areas. Life Science courses are taught by a variety of instructors with differences in their understanding, views and opinions regarding the process of science as well as their pedagogic approaches to teaching this process. We initially investigate the views of lecturers regarding hypotheses and experimental design in their personal research in the Schools of Agriculture, Earth and Environmental Sciences and Life Sciences at UKZN, and how these compare to what is taught at the introductory biology level. Interestingly, only 46.7% of the respondents conduct hypothesis-driven investigations and less than 7% use predictions in their personal research. There is also much variation in faculty members’ ideas regarding research hypotheses, alternative hypotheses and their use of sample size, repetition and randomization in their personal research. Critical analysis of faculty’s approach to undergraduate teaching of Life Sciences indicates an over-emphasis of content teaching rather than the development of scientific reasoning and critical thinking. Undergraduate courses need to engage Life Science students in the process of scientific inquiry where they are encouraged to think deeply about the process of science, and in particular experimental design. Successful Life Science courses train students to critically evaluate experimental design, statistical approaches and inferences in its entirety. Consequently, we tested first and second year Life Science undergraduates understanding of various aspects of experimental design using an open-ended questionnaire. We found that undergraduates performed poorly in 1) producing a completely randomized design of treatments 2) describing the benefits of limiting sources of variability and 3) describing the limitations to the scope of inference for a biologist. They only showed improvement from first to second year in their ability to correctly identify treatments from independent variables. These results add to the growing body of Life Science research that indicates that undergraduate curricula are not adequately producing well-rounded, critical thinking scientists. Next, we focus on assessments. Faculty staff have been challenged by science educators to change their approach to teaching in order to more accurately reflect the practice of biology. Meeting these challenges requires the critical analysis of current teaching practices and adjustment of courses and curricula through curriculum reform. Assessments play a vital role in providing evidence of effective instruction and learning. Student responses from two formative tests and one final summative examination for an undergraduate biology cohort (n = 416) at UKZN were analyzed both quantitatively and qualitatively to determine students understanding of aspects of the scientific method. Quantitative analyses revealed that the majority of first-year undergraduate students at the end of an introductory biology course were able to identify hypotheses and dependent and independent variables correctly. However, qualitative analyses indicated that sometimes students confuse hypotheses with predictions and are unable to identify independent variables correctly. Critical analyses of the assessments using the Blooming Biology Tool revealed that assessment design can considerably influence student results. It is essential that clear objectives and competencies are set at the outset and that there is a synergistic relationship between instruction and assessment. Assessment design requires careful consideration of content being covered as well as cognitive skills being tested throughout the course. In addition, we determine the types of conceptions that third year biology students’ hold regarding hypotheses, predictions, theories and aspects of experimental design. These conceptions were compared across two geographically separated campuses of the UKZN, namely the Pietermaritzburg (n = 28) and Westville (n = 50) campuses. They were also compared to descriptions located in prescribed textbooks and course manuals throughout their undergraduate biological studies. Results indicate that there is variability between and across campuses in students’ descriptions of research hypotheses, predictions and theories, repetition and randomization. These conceptions were sometimes partial conceptions while in other instances they were completely incorrect. Interestingly, many of the students’ responses lacked essential elements which could be found in the prescribed textbook and course manuals. The variability in student responses across campuses could be a result of differences in faculty instruction and therefore more research is required to test this. These results also indicate the necessity for courses to be designed with more consistency in concepts to be developed. Lastly, we focus on students’ competency in aspects of scientific inquiry revealed through a third year research project that is mentored by faculty staff members. This chapter is designed to describe students’ ability to effectively apply scientific inquiry at the undergraduate exit year. Biology 390 projects were analyzed from 2012 (n = 26 students), 2013 (n = 46 students) and 2014 (n = 34 students). Journal formatted project write-ups were examined for reference to aims, objectives, hypotheses and predictions. Students’ ability to appropriately apply experimental design was also assessed by documenting their use of replicates, sample size, randomization and controls. Conceptions of the broad nature of the scientific process and scientific inquiry were also noted by surveying project introductions, discussions and conclusions for evidence of students’ ability to link their research into the greater network of scientific knowledge. There was an overemphasis in the use of statistical hypotheses compared to scientific hypotheses by BIOL 390 students in their project write-ups. Many students used predictions inappropriately and a large majority of students failed to incorporate critical aspects such as randomization and controls into their experimental designs. Explicit didactic discussions by mentors with their students are necessary in order to improve these conceptions of the scientific process. It is suggested that mentors become familiar with both learning theories and common misconceptions associated with the nature of science and scientific inquiry so that they are able to apply these to their mentoring approaches of students conducting research projects. As a whole, this thesis finds a general lack of understanding of the basic premises of what entails “science” at all levels of undergraduate study within the Life Sciences at UKZN. This worrying trend reflects research from elsewhere, and suggests reform is needed to ensure that UKZN can produce critical higher-order thinking science graduates capable of correctly understanding the full intricacies of the variety of approaches to conducting scientific research. Suggestions for reform include the need for Faculty staff to engage up to date pedagogical research on how science should be taught, a recognition that a move away from knowledge transfer alone towards including skills transfer is needed, training for faculty staff in terms of mentoring skills for participatory research experiences for undergraduates that includes scientific process mentoring, and curriculum reform that recognizes the need to set clear measurable objectives and outcomes for undergraduate courses. Lastly, we also recommend analyzing assessment types used at UKZN in order to ensure that sufficient higher-order cognitive skills are assessed, rather than predominantly lower-order cognitive skills as is currently the case.