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This study assessed students' learning of evolution by natural selection within four different sections of an introductory biology course. Each section used a different combination of curricular materials (either traditional or historically rich materials) and instruction (either paired problem solving or traditional lecture). Students in the study completed pre-and postintervention evolution tests. Students' responses were analyzed to create variables for both correct and alternative conceptions of evolution. Pretest and posttest data were used to create difference scores that were compared both within and between teaching sections. Pre-to-post gains were expected in the correct (Darwinian Conception) scores, while pre-to-post losses were expected in the Alternative Conception scores. Also, students in the experimental sections were expected to perform better than those in the traditional sections. Pretest-to-posttest differences within each section showed gains in correct conceptions but few reductions in alternative conceptions. Comparisons between sections support the use of the paired problem-solving instructional strategy in conjunction with the historically rich curriculum.

A historically rich teaching intervention was developed for biological evolution with the intent of promoting a conceptual change from students' initial understanding to a more Darwinian understanding. The intervention was delivered in a small group setting to underprepared, entry-level biology students. Evaluation of the treatment, using pre-post testing, was used to document the general effectiveness of the intervention and specific changes in students' conceptions of evolution. Results indicate the use of historical materials in conjunction with a conceptual change strategy to be promising. Specific strengths and weaknesses in specific areas of biological evolution are documented. 0 1995 John Wiley & Sons, Inc. OVERVIEW PurposeThe teaching of Darwinian evolution is critical to understanding modern biology, yet it has been shown to be quite difficult (Bishop & Anderson, 1990;Brumby, 1984;Clough & Wood-Robinson, 1985; HalldCn, 1988; Smith et al., in press). This study is the evaluation of an intervention in the teaching of evolution. The intent was to conduct an ecologically valid study by examining the effects of the intervention within the time limits of a typical introductory biology course for underprepared students. The intervention was the teaching of ideas that have been important in the history of evolutionary thought in a way that meets the conditions for learning given in conceptual change theory. The intervention was done in a laboratory session associated with a biology course for nonscience majors. The evaluation was conducted as an in-depth examination of the changes in the students' knowledge that were associated with the intervention. The overall thesis of this study was that if instruction recapitulated events in the development of the Darwinian theory of evolution by natural selection, then students would replace their initial conceptions with more Darwinian conceptions.

The goals of this study were to determine preservice science teachers' views of the nature of science and to describe the changes in those views that occur during a teacher education program. Fifteen students in a postbaccalaureate secondary science teaching program at a large university participated in this study. The participants' views of science were ascertained by an investigator-developed survey and a follow-up interview administered before and after the university's science teaching methods sequence. Before entering the teaching program, the participants had a contemporary (i.e., postpositivist) view of scientific theory, knowledge, and the role of a scientist and a traditional (i.e., empiricist or positivist) view of scientific method. Initially, there was an equal number of traditional, mixed, and contemporary views of the different aspects of science. After completing the methods sequence, the number of contemporary views doubled and the number of mixed views decreased by more than half. The number of participants with an overall contemporary view of science rose from 2 to 7. Since there was little direct instruction about the nature of science, it is possible to make positive changes in preservice teachers' views of the nature of science in a teaching program in which contemporary teaching strategies such as conceptual change and cooperative learning are taught.

Recent research related to the design of science instruction is often based on conceptual change theory and requires assessments of what knowledge students bring to instruction. The premise of this study was that it is also important to understand when and how students apply their knowledge. Fourteen elementary and middle school teachers in an in-service physics course were asked to solve qualitatively a variety of series and parallel circuit problems and explicate their reasoning. These teachers were found to share a common core of strongly held propositions that formed a coherent, but incorrect and contradictory model of sequential current flow. Yet their predictions about the circuits were highly variable. The variability in predictions resulted from differences and contradictions in additional "protective belts" of propositions, and differences in the ways in which the teachers changed and selectively applied those propositions to different problems. Understanding the variations in not only what teachers knew, but also the differences in when and how they applied their knowledge complicated the task of designing instruction. However, it also made possible the design of more precise instruction in which the teachers were required to recognize, confront, and reconcile specific inconsistencies in their beliefs.

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During the past twenty years, research, curriculum development, and instruction in science education have been influenced by Gagne's conception of science processes. This article reports an investigation of the epistomologic foundations of this conception. The results indicate that a commitment to inductive empiricism pervades the presently held view of science processes. A major tenet of this commitment is that conceptual knowledge results from the application of science processes in understanding natural phenomena and solving problems. Criticism of the commitment in light of recent developments in the philosophy of science reveals that there is limited philosophical support for this view. The implication is that if science educators continue to use the presently held view of science processes, the conception needs to be reformulated. Otherwise, there is a clear danger that students will be presented an inaccurate and inadequate view of science processes. The alternative is to view the exact nature of science processes as being dependent upon the conceptual knowledge that is used to understand a particular phenomena or problem.Since the mid-l800s, science educators have argued that the processes of science should be taught as a part of school curriculum.

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