Charlene D'Avanzo

Application of Research on Learning to College Teaching: Ecological Examples

Abstract Encouraged by improvements in the quality of science education since the 1960s, cognitive researchers are testing and applying theory-based research on learning in science classrooms. To introduce faculty to research on cognition and learning, I focus on metacognition: the awareness of ones own thinking, or “knowing what we know.” I analyze two ecology texts and describe several active-learning strategies in the context of metacognitive theory. Information about pedagogy and its theoretical underpinnings may well help faculty improve their teaching practices.

Research on learning: potential for improving college ecology teaching

Recent research has changed our understanding of how people learn. These findings are based on well-established learning theories that can potentially help faculty teach more effectively. Unfortunately, most science faculty, including ecologists, have little or no exposure to research on learning or its application to teaching. In this paper, four areas of research on knowledge and learning are given as the basis for an approach designed to help students overcome the common misconception that plants do not consume oxygen. To help improve college ecology instruction, ecology faculty and researchers who study learning should collaborate to design research about ecology teaching and ecological thinking.

Use of Detrital Foods and Assimilation of Nitrogen by Coastal Detritivores

Two killifish common in east coast U.S.A. salt marshes,Cyprinodon variegatus Lacepede andFundulus heteroclitus Walbaum, differ in their ability to assimilate nitrogen from and grow on detritus.C. variegatus grew on a diet of detritus ofSpartina alterniflora Loisel, whileF. heteroclitus did not. In addition, when the fish were fed15N-labeledS. alterniflora detritus,15N:14N ratios inC. variegatus were higher than were ratios inF. heteroclitus. Therefore, even though both species ingest large amounts of detritus,C. variegatus makes more effective use of this portion of its diet. These dietary differences are corroborated by anatomical differences that suggest thatC. variegatus should make better use of detrital or plant tissues thanF. heteroclitus. In the label experiment, the degree of label in both fish was directly proportional to the degree of label in the food treatments. In previously published experiments designed to compare plant substrate with attached microbes as nitrogen sources for detritivores, %15N incorporated by a polychaete was also directly proportional to %15N in the detrital food. Therefore, it is difficult to distinguish between plant substrate and microbes as nitrogen sources for this detritivore.

Nitrogen assimilation from amorphous detritus by two coastal consumers

Abstract The food value of recognizable pieces of dead vegetation, morphous detritus, has been the focus of many studies in coastal systems. In contrast, the nutritional quality and formation process of amorphous detritus, aggregates of dissolved organic matter (DOM), is poorly studied. We created 15 N-labelled aggregates from the leachate of four macrophytes, a marsh grass and three macroalgae common in New England coastal waters. We fed the labelled aggregates to two coastal consumers, the grass shrimp Palaemonetes pugio and the sheepshead minnow Cyprinodon variegatus . Fish and shrimp fed each of the labelled aggregates became labelled with 15 N. This study provides direct evidence for nitrogen assimilation from amorphous detritus by marine consumers. In addition, fish fed amorphous marsh grass detritus assimilated 10–40 times more nitrogen from this detritus than from morphous grass detritus. Therefore, amorphous aggregates may be higher-quality food than morphous detrital fragments for coastal consumers.

Teaching with principles: toward more effective pedagogy in ecology

Ecology is a complex and dynamic field and, as communicators of our discipline, faculty should be able to define a set of core principles that underpin and create ecological pattern and process. The pedagogical value of defining and drawing on a concise set of disciplinary principles and concepts is well grounded in research on cognition. Here, we present a set of seven core ecological principles from a graduate-level course in ecology as an example of how a pedagogical approach based on principles can provide students with essential components of a mental model shared by their instructor and classmates, and from which a deeper understanding of ecological pattern and process can be achieved. We also provide a series of recommendations to stimulate faculty to think more deeply about the teaching and learning of ecology so that they can identify a set of concepts and principled reasoning appropriate for their teaching circumstance.

The relationship of diet to growth and ammonium excretion in salt marsh fish

SynopsisDetritus is an abundant but poor quality food source for consumers in salt marsh ecosystems. Here we present results of feeding experiments to determine the ability of Fundulus heteroclitus, Cyprinodon variegatus, and Mugil cephalus, three major detritivores in Great Sippewissett Marsh, Massachussetts, to assimilate detritus and use it for growth. C. variegatus, the sheepshead minnow, gained weight on a detrital diet, but F. heteroclitus, the marsh killifish, and juvenile M. cephalus, the striped mullet, lost weight and suffered high mortality on detrital diets. C. variegatus is a herbivore with morphological adaptations for ingesting plant material. F. heteroclitus is a carnivore poorly suited to effectively assimilate detritus from the diet. Although adult M. cephalus are adapted for ingesting and assimilating detrital material, the young may lack these adaptations and thus do not assimilate detritus. C. variegatus excretes ammonium at a lower rate than F. heteroclitus when fed animal food, or when starved for short periods of time. This protein sparing effect could be crucial for survival when detritus is the only food available at certain times of the year. While both C. variegatus and M. cephalus are visitors in the marsh and may leave to exploit food sources elsewhere, F. heteroclitus is a year-round resident and is the most abundant species of fish in the marsh. Yet when high quality food sources become scarce in late summer and fall, detritus, although plentiful, is apparently not a suitable alternative.

Design and evaluation of TIEE, a peer‐reviewed electronic teaching resource

“Teaching Issues and Experiments in Ecology” (TIEE) is a peer-reviewed electronic publication designed to help ecology faculty improve their teaching. The Ecological Society of America (ESA) electronically hosts TIEE, which is an important part of the Societys contribution to the BioScience Education Network, a pathway of the National Science Digital Library. A central part of each TIEE “Issue” (mainly for use in lectures) and “Experiments” (for inquiry-based labs) are published figures, genuine datasets, and open-ended investigations. Surveys and interviews show that users teach both at liberal arts colleges (61%) and research universities (26%), and that TIEE provides a much-needed outlet for peer-reviewed education scholarship. Over 75% of respondents to our survey (n = 59) adapted TIEE materials for their courses and 30–50% used TIEE as a model for changing their method of teaching. In addition, over 60% said that publishing in TIEE would be valued in reappointment or tenure decisions. Evaluation fin...

Evaluation of ENDECO 1184C dissolved oxygen recorders for use in temperate estuaries

Abstract Pulsed Clarke-type electrodes, a relatively new type of dissolved oxygen (DO) sensor, were intended to minimize problems associated with sensitivity to flow and biofouling-problems which affect most oxygen sensors. The commercially available devices (ENDECO/YSI, Inc., Model 1184C), which include temperature and conductivity sensors and a data logger, are designed for coastal environmental monitoring at depths to 30 m. In order to evaluate their performance under field conditions, a series of field deployments and laboratory calibrations was conducted, and the instrument output was compared with precision Winkler titrations. Accuracy of reported DO concentrations varied both between instruments and with time. Errors typically ranged from 0 to 3 mg/l. Thus frequent calibration seems to be a requirement for the accurate use of these units. The recommended 1-point calibration update did not improve accuracy. In the laboratory, the response to varying DO concentrations at constant temperature was highly linear over a range of approx. 5–14 mg/l; both accuracy and response time decreased at low DO concentrations, somewhere between 0 and 1.5 mg/l. Potential sources of inaccuracy in DO measurements include (1) statistical error associated with the estimation of calibration constants, and (2) operation of the instrument near the extremes of the temperature range used to calibrate it. We found support for the claim that the instruments are relatively insensitive to fouling.