Biology: Presenting Evolutionary Theory

Title: Presenting Evolutionary Theory to Introductory Biology Students
Discipline(s) or Field(s): Biology
Authors: Anne Galbraith, Roger Haro, David Howard, Jennifer Miskowski, Dan Sutherland, University of Wisconsin-La Crosse
Submission Date: October 2007

Executive Summary: Many of our students come into this introductory biology course with very little background in evolutionary theory. Yet evolution provides the foundation for understanding all of modern biology! At the end of this lesson we hoped that students could
  1. understand and appreciate evolution as a scientific theory that is fundamental to all of biology,
  2. clearly explain how evolution works,
  3. use examples that show supporting evidence for evolution.

We developed a series of PowerPoint slides that began by introducing Charles Darwin as a man by taking advantage of a recent series of articles in the lay press, including magazines such as Natural History and National Geographic. We then went through Darwin’s logic in formulating his theory based on his observations while a naturalist on the HMS Beagle. We emphasized that Darwin’s contemporaries were simultaneously formulating similar theories. We provided evidence of other adaptive radiations besides the famous Galapagos finches such as cichlid fish and the Hawaiian honeycreepers. We then explained the principles of evolutionary theory and showed how they applied to these examples that had just been presented.

After this, we had an in-class assignment in which we presented increasingly useful information about a variety of mammals from which they had to produce a phylogenetic tree showing the relationships among these mammals. First we gave them information about the animals’ habitats and feeding habits. Then we introduced the concept of using skeletons and comparative anatomy and had them re-draw their trees. Then we introduced the concept of using DNA sequences and comparative genomics to show relationships and had them re-draw their trees once again. After this, we showed them the current “real” tree and showed them pictures of the common ancestor for these modern mammals for which fossils had been found recently. Finally, we gave them an out-of-class assignment which required them to use three other articles and the internet:
  1. to find examples of “transitional fossils” which creationists claim are few and far between,
  2. to find examples of “evolution in action” which creationists claim do not exist except for microevolution,
  3. to answer questions about the Hox genes which are conserved in organisms as diverse as fruit flies and humans. In another lecture section, we shared their work with the class.
We hoped that the human approach to presenting Charles Darwin would alleviate the preconceived ideas by some of our students that he was an “evil atheist”. We hoped that by presenting them with a myriad of examples that are not “worn out”, and by forcing them to find even more examples on their own with an assignment out-of-class, that they would understand the theory better and find it more difficult to just toss this theory aside.

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