Friday, December 4, 2009

Defining Evolution in Anthropology Textbooks

Here's one of the most interesting articles in the current edition of Evolution: Education and Outreach.
White, J., Tollini, C.D., Collie, W.A., Strueber, M.B., Strueber, L.H., and Ward, J.W. (2009) Evolution and University-level Anthropology Textbooks: The “Missing Link”? Evo. Edu. Outreach 2:722–737 [doi: 10.1007/s12052-009-0176-6]

Abstract: Although studies analyzing the content of evolution curriculum usually focus on courses within the context of a biological sciences department or program, research must also address students and courses outside of the biological sciences. For example, using data solely from biological courses will not fully represent the scope of coverage of evolution in university education, as other fields, like anthropology, also utilize evolutionary principles. We analyzed the content of 31 university-level anthropology textbooks for the following: (1) presence of a definition of evolution in various sections of the textbooks, (2) accuracy and consistency of the definitions provided in the textbook sections, and (3) differences between textbooks for cultural and physical anthropology. Results of this study suggest that anthropology textbooks do not necessarily (1) provide a single definition of evolution or (2) provide an accurate, “baseline” definition of evolution when present. Additionally, substantive differences were observed between definitions provided in different sections within a single textbook, as well as between textbooks written for cultural anthropology and physical anthropology/archaeology courses. Given the inclusion of anthropology courses in general education curriculum at the university-level, we conclude that this situation may further exacerbate the misunderstanding of the basic tenets of evolution that university students have been repeatedly shown to demonstrate. We stress the role of the instructor in choosing textbooks that provide accurate information for students, as well as the responsibility they hold in providing a concise, accurate definition of evolution in social sciences courses.
The authors refer to an earlier study by Linhart (1997) who examined definitions of evolution in biology textbooks.
In our literature search, we were able to locate only one study that directly addressed the coverage of evolution in textbooks. Linhart (1997) focused on textbooks designed for one of the following six courses in the biological sciences: general biology (for majors and non-majors), evolution, genetics, paleontology, ecology, and systematics. He restricted his sample to 50 textbooks that had multiple editions and a sizable market share, and he located at least some of these textbooks using colleagues’ recommendations. He analyzed the content of the glossary entry for evolution in each textbook, as well as the material in any pages listed in an index entry for evolution, and compared these data against a definition of evolution he constructed after reviewing the literature:
Evolution is said to have occurred within a species, lineage, or population when measurable changes in various morphological, physiological, behavioral, or biochemical characteristics can be detected. These characteristics must be at least partly under genetic control. The genetic change(s) can occur as a
consequence of processes such as migration, mutation, genetic drift or bottleneck, natural selection, and nonrandom mating. Genetic changes within different populations of a species can lead to differences among lineages, and sometimes to the origin of new species...Evolution is not a synonym of natural selection. Nor is evolution a process that leads inevitably to increased or improved adaptation, or to greater reproductive success. Evolution does not imply a progressively closer fit between a population and its environment. Finally, evolution does not involve predictable or irrevocable changes from simple to more complex forms or toward some sort of perfection (Linhart 1997: 387).
While he found variation between the textbooks written for the six different courses in his sample, his findings indicated that the majority of all of the textbooks equated evolution with natural selection or adaptation and did not describe evolution in much detail. Linhart (1997) expressed much concern regarding the content of the definition of evolution in these textbooks, arguing that many students will have an inaccurate or incomplete view of evolution unless they are provided with additional material.
I agree with the problems that Linhart outlines and I agree that evolution needs to be defined as a process that involves genetic change and populations. It's very important that evolution should be defined in a way that allows for multiple mechanisms such as natural selection and random genetic drift.

Most of the biology textbooks I've read do an adequate job of defining evolution but I haven't covered as many textbooks as Linhart.

It's disappointing that biology textbooks and anthropology textbooks do such a poor job of defining—and presumably explaining—evolution. Is it any wonder that the general public is scientifically illiterate when we can't even get it right in the textbooks?


Linhart, Y. (1997) The teaching of evolution: we need to do better. Bioscience 47:385–91.

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