University of Oregon Biology Software Lab Download Page

You may download the free software on this page immediately. Simply click on the title of the file or program you wish to download. WE NO LONGER REQUIRE an ID or PASSORD Software is packaged with user's manuals and curricular materials.Unfortunately, no support is currently available. All the files are compressed in Binhex format.

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Cumulative Selection

(Requirements: System 7.O, 2MB RAM.)

One of the most frequent arguments one hears against the theory of evolution is that complex forms and behaviors simply couldn't have evolved by "random chance" alone. The point we must often get across to students is that evolution does not, in fact, work this way; change is cumulative. In the "Blind Watchmaker", Richard Dawkins dispels the myth of random chance by using the very metaphor that opponents of evolution often turn to: the monkey at the typewriter. This program models his suggestion that, were a monkey allowed to type random letters, he would produce a work of Shakespeare relatively quickly if letters he happened to type in the right places were preserved with each attempt. With this program, students type in a phrase of their choosing and observe how long a random phrase takes to "evolve" into their target phrase.

Students can choose the target phrase, set a mutation rate, set the number of "parent" phrases, and the number of "offspring" phrases per parent to see how each of these variables affects the rate of evolution.

Here is a sample investigation.

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Selection in Action

(Hypercard Stack. Requirements: System 7.0, Hypercard 2.0 or later, 2MB RAM)

Many biology courses include some kind of lab activity to demonstrate natural selection in which students simulate the role of "predators" on populations of beans or beads of different sizes or color.

"Selection in Action" is designed to be used in conjunction with such an activity. It not only does the work of calculating gene frequencies in the next generation based on data students enter, it presents situations which challenge students to create and test hypotheses about the patterns of change they observe. The program presents a series of "planets" whose populations differ in terms of mechanisms of heredity, variability, population size, and other characteristics. Students, unaware of these characteristics, must make observations, generate hypotheses, and design tests in order to construct explanations for what they observe. In this way, the activity effectively confronts students' misconceptions about the role of heritable variation in evolutionary change, and allows them to explore the effects of environment and population size in different situations.

Figure 1. The Selection in Action spreadsheet

Figure 2. Extensive built-in authoring capabilities enable instructors to create a wide variety of problems for student investigations. This flexibility not only makes Selection in Action! an effective teaching tool, but also an innovative method for testing students' understanding of these priciples. Furthermore, access to authoring tools is password-restricted so that problems cannot be inadverently changed.

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last update March 16, 2003 (udovic@uoregon.edu)