Extinction is Forever: Gambler's Ruin and Random Walks
Summary
In this activity students model random walks and their relation to extinction, both by randomly walking (an exercise by David Goldsmith, linked in the lesson plan) and by modeling various scenarios of the 'Gambler's Ruin' thought experiment in R.
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Context
Audience
I use this in my 400-level Paleobiology course
Skills and concepts that students must have mastered
Students must have some understanding of extinction.
Students must have some working knowledge of R. (This can be as basic as how to open R and how to copy/paste. They only need to change a few values in the code)
How the activity is situated in the course
This is a stand-alone exercise in my extinction module.
Goals
Content/concepts goals for this activity
Students can explain what a random walk is and explain how they can be used as null models in paleobiology.
Students can explain why extinction is inevitable.
Students can explain how a 'first strike' can lead to extinction.
Higher order thinking skills goals for this activity
Relating physical and mathematical models to paleontological processes. Explaining how random processes can create patterns.
Other skills goals for this activity
Practice using R
Description and Teaching Materials
Students begin the exercise with a random walk exercise where they randomly walk along a course I set up. After this physical exercise is done, we relate that to models of random walks in R. Details are in the lesson plan below.
Gambler's Ruin Lesson Plan (Microsoft Word 2007 (.docx) 8kB Feb23 23)
Gambler's Ruin Worksheet (Microsoft Word 2007 (.docx) 11kB Feb23 23)
Teaching Notes and Tips
You need some space to do the actual random walks, I generally use the quad if it is a nice day. Students may need a refresher on how to modify R function parameters.
Assessment
The questions in the worksheet are graded for credit.
References and Resources
Raup, David M. "Extintion: bad genes or bad luck?." Acta geológica hispánica (1981): 25-33.