It has recently come to our attention that with the inclusion of the Gateway standards in the Tennessee high school biology curriculum, which require the coverage of evolutionary principles, many teachers are choosing to exclude human-related examples. We support and applaud the effort that administrators have made to insure the inclusion of evolution in the curriculum of high schools across the state. However, while we are sensitive to the fact that broaching this topic may be difficult for many individuals because of cultural beliefs or religious convictions, we find the exclusion of human evolution to be incompatible with the goal of integrating evolution throughout the biology curriculum. We are further disappointed because there are excellent examples from humans and closely related lineages that uniquely illustrate many evolutionary principles. Many students would find the discussion of these topics both relevant and intriguing, and their inclusion would help students appreciate relationships between ourselves and other organisms living on this planet. These points are outlined in more detail below:
1) Exclusion of human examples is incompatible with an accurate presentation of key ideas in biology in the curriculum.
Discussion of evolution in a topical framework is inadequate. Instead all topics in biology should be presented with an historical perspective. This approach makes the discussion of our historical relationships to other organisms inevitable. For example, all subjects in biology are enhanced by an evolutionary context from molecular (e.g., the universal nature of the genetic code), cellular (e.g., the origin of mitochondria), to developmental biology (e.g., similarity in early embryonic development among mammals) and the discussion of whole organisms (e.g., homological relationships in the anatomy of appendages in birds, bats, whales, etc.). Discussion of biology in an evolutionary framework would not only be more accurate, but would also render the subject matter intrinsically more interesting to students.
2) Examples from human evolution uniquely illustrate many evolutionary principles.
In humans and closely related species we have a relatively complete and well documented data base supporting evolutionary relationships. This is particularly true for a range of molecular and DNA sequence analyses that have been completed for humans and other primates from around the world. These molecular data combined with the available fossil evidence provide a substantial picture of the origin and migration patterns for human ancestors and related lineages. Presentation of salient examples from this information base (e.g., the disappearance of the Neandertals) would emphasize the "branchy" nature of our family tree and help erase inaccurate perceptions of linear progressions of fossil types that are still prevalent in the popular media.
3) Inclusion of human examples is crucial to communicate the relevance of evolutionary principles.
Much of the typical high school biology curriculum concentrates on human biology and human health issues. The delegation of evolution to a limited and focused presentation (the topical approach mentioned above) during which only non-human examples were used would provide the false impression that these principles have only limited application. Obviously teachers and textbook authors have chosen to provide a human focus for high school level because it facilitates increased interest and learning for these students. Utilization of human examples would emphasize the relevance of historical relationships among organisms and would be more likely to promote discussion and consideration of evolutionary principles in the broader context of biology.
Mitch Cruzan, President
Tennessee Darwin Coalition
Department of Ecology and Evolutionary Biology
University of Tennessee, Knoxville