Why Reproduce? A Demonstration of Evolution and the Origin of Life

Abstract

One of the main goals of general biology programs is explain the process of evolution. Despite long discussions of the process and its consequences, I have found students often retain their view of evolution as goal oriented, with organisms almost shopping around for a set of improved characteristics. This view is so locked into their minds that presenting a simple visual demonstration of the process seemed advisable. As a countermeasure, I developed a simple model illustrate several aspects of the biochemical theory of the origin of life and the process of evolution through natural selection. This model has students predicting the outcome of evolution in populations of beads. Since the underlying principles of evolution are so important in a general biology course, and, since student resistance learning them seems so high, I spend 45-50 minutes (and an almost equivalent time in the laboratory) working through this model with the class. I want the students themselves feel that the outcomes are obvious and inevitable so that their resistance learning the principles is overcome. This course segment fits topically between mitosis and meiosis. I begin it by addressing two questions: do cells divide? and do organisms reproduce? The most frequent responses from students these questions are, respectively, some variation on to help the organism survive and to perpetuate the species. By having them think about the cells in their own hands and algal cells in a stagnant pond, I convince them (I hope) that such teleology is absurd. I then point out that I want show them why my question reproduce? is the wrong question. A Model of Evolution