Explanation of SFAA Section Links

Course Rationale

It is important to note that this evolution lecture and laboratory are designed for students majoring in the natural sciences. While students outside such majors are eligible for enrollment (such as students in secondary science education), the goals of the course exceed the specific literacy requirements for evolution as described by SFAA. Instead, the instructor's goal for this class is to allow students to understand the historical nature of evolutionary biology as well as understand and be able to apply a variety of basic evolutionary concepts to make sense of biological phenomena.

To assure that students both understand and are able to apply a variety of concepts, the instructional design assumes that students enter the class with a degree of scientific literacy. To be successful, students must enter the course with a basic, yet functional, understanding of: natural history, genetics, biological diversity, geological time, and mathematics. Therefore, these areas were not the focus of instruction. Instead, instruction extends from this knowledge base and stresses the historical development of evolutionary thought, various mechanisms of evolutionary change, species concepts, geographic variation, speciation, and macro-evolutionary phenomena. The conceptual framework detailed in this course is far more complex than the fundamental literacy description of SFAA.

While the construction of a complex conceptual framework is to be expected in an evolution class designed for majors, the strong emphasis on the nature of science and scientific habits of mind was unusual. This emphasis is best demonstrated by the instructor's closing remarks for the course:

In this course, we've focused on evolutionary concepts and principles as well as the nature of science. So, if you learned nothing else this semester, I hope you learned that: science is tentative (rarely are there "absolute truths"); science is self-correcting (by means of hypothesis testing); and in science, healthy skepticism or critical thinking is a virtue, and not a threat to established doctrine. [Instructor's emphasis, lecture 36]

The emphasis on the nature of science and scientific habits of mind were interwoven throughout instruction. While concepts were seldom the focus of declarative knowledge statements, they were constantly applied in explanations of evolutionary concepts and the myriad studies that have resulted in this body of knowledge.

Rationale for Central Topics

Nature of Science

Describing the nature of science through an analysis of the development of evolutionary thought and ongoing research programs formed a major theme of the course. Aspects of the nature of science addressed in the class included sections on the Scientific World View and Scientific Inquiry. The means through which scientific knowledge is modified and the durability of scientific knowledge claims were the focus of instruction. These topics were addressed through analysis of both the historical development of evolutionary theory as well as comparisons of current competing scientific conceptions, such as rival species concepts and descriptions of the patterns and rates of evolutionary change. Throughout the course, concepts were deductively introduced; the instructor provided a definition and analyzed the research project that produced the concept. This instructional pattern emphasizes the process of scientific inquiry by stressing the centrality of evidence for production of a knowledge claim, demonstrating how any scientific argument must be logically sound, and illuminating how research hypotheses play central roles in scientific inquiry.

Not all the topics listed within the nature of science chapter were central components of the course. Topics of experimental bias, expertise versus authority, and an understandable world were not addressed explicitly through instruction. However, given that this course was directed toward conceptions of biological evolution, we do not view these omissions as flaws. Instead, if each science course taken by an unergraduate had such a through treatment of the nature of science, we might expect science majors to exit the university with a wealth of knowledge in this area.

The living environment

Within the SFAA chapter dedicated to the living environment, it is not surprising that the majority of attention in the course addressed the section on the evolution of life. However, topics within two related sections, Diversity of Life and Heredity, also formed major components of the course. Classification, a topic in the section Diversity of Life, was a central focus of the class. Instruction emphasized species concepts and the related assumptions that form the basis of each of the various research programs. While the treatment of species concepts was an excellent avenue to display the tentative and self-correcting nature of science, this topic also provided students with a deep understanding of the dynamics of natural populations and lead them to a later understanding of the process of speciation. As was the case with much of the content of the class, the treatment of species concepts far exceeded the complexity reflected in the SFAA document.

Clearly, an understanding of genetics is an essential component for a scientific conceptual framework based on the New Synthesis (Fisher, 1992). Although much of the course assumes a basic literacy in genetics (such as would be achieved in an introductory biology class), one important concept was stressed through instruction: the production of variation in a population. Such an overt emphasis on the link between evolution and genetics is pedagogically necessary, as past research has shown that students are largely unsuccessful in linking their knowledge of the two fields (Demastes, Good, Sundberg, & Dini, 1992). Topics related to this concept include variation produced through the sorting of genetic information that occurs during sexual reproduction and the mutation of genetic material. Although one might expect that these topics were already mastered by students having completed introductory courses, understanding the production of variation is a logical pre-requisite for understanding the various processes of evolutionary change. Without variation, there can be no evolution. Therefore, without understanding how variation is produced, a student cannot logically understand how evolution proceeds.

The instructor's emphasis for the class was on an understanding of the process of evolutionary change, both on a micro-scale and macro-scale. Natural selection, as one of the mechanisms of change, received a great deal of attention. Other mechanisms, not included in SFAA, such as genetic drift and variations on the theme of natural selection, such as nonrandom mating, were also the focus of attention. Thus, the class far exceeded the literacy requirements and required students to develop a complex and sophisticated understanding of the various processes of evolutionary change.

Fossil and molecular evidence for evolution is another topic related to the SFAA section, Evolution of Life. Although this topic did receive some attention, clearly it was not as central to the course as knowledge of evolutionary mechanisms. The instructor's goal for the course was for students to understand the process of evolutionary change, not to cite evidence supporting the construct. However, the class analysis of the historical development of the construct did serve to showcase evidence paramount to this development. Through this, not only did students gain an understanding of how evolutionary theory developed, they also gained an understanding of the evidence that sparked this development.

Finally, the emphasis placed on understanding the processes of evolutionary change allowed students to understand the patterns of change, such as those mentioned in the SFAA topic, increasing variety. A central component of the class addressed common misconceptions of teleological evolutionary change. The examples addressed served to portray evolutionary change as more random and less goal-directed than is commonly conceived. Although not a great deal of time was spent on this concept, the large amount of attention given to mechanisms informed the class' examination of evolutionary patterns

The human organism

The lecture and laboratory course culminated with an analysis of human evolution, directly addressing the topic of Evolution from simpler organisms in the section of Human Identity as described by SFAA. As in the rest of the course, the historical reality of human evolution was not debated; instead, instruction assumed this knowledge. The course focused on the details of human phylogeny and the anatomical and molecular evidence for this phylogeny.

Historical Perspectives

Much emphasis in the course was placed on the historical development of evolutionary thought, an emphasis that we feel is unusual in similar evolution courses. For the SFAA section, the Diversity of Life, topics of (a) acquired features versus natural selection, (b) evolutionary theory and resistance to it, and (c) the genetic basis of evolution were addressed fully during the semester of instruction. This treatment served many pedagogical purposes beyond simplistic historical recitation; addressing current alternative conceptions through analysis of historical conceptions (Duveen & Solomon, 1994), displaying the tentative and self-correcting nature of science (Duschl, 1990), and analyzing the evidence that lead to the development of evolutionary constructs (Zuzovsky, 1994).


References

Demastes, S. S., Good, R. G., Sundberg, M., & Dini., M. (1992, March). Students' conceptions of natural selection: A replication study and more. A paper presented at the meeting of the National Association of Research in Science Teaching, Boston, MA.

Duschl, R. A. (1990). Restructuring science education: The importance of theories and their development. New York: Teachers College.

Duveen, J., & Solomon, J. (1994). The great evolution trial: Use of role-play in the classroom. Journal of Research in Science Teaching, 31, 575-582.

Fisher, K. M. (1992). Teaching of evolution. In R. G. Good, J. E. Trowbridge, S. S. Demastes, J. H. Wandersee, M. S. Hafner, & C. C. Cummins (Eds.), Proceedings of the 1992 Evolution Education Conference (pp. 103-108). Baton Rouge, LA: NSF/LSU.

Zuzovsky, R. (1994). Conceptualizing a teaching experience on the development of the idea of evolution: An epistemological approach to the education of science teachers. Journal of Research in Science Teaching 31, 557-574.