Modeling Tiger Stripes

Activity Concept


Undergraduate STEM majors will have an opportunity to manipulate MATLAB code to address a driving question. They will engage with a simplified model to develop comfort editing code and analyzing the results of those edits. They will then work with complex code to manipulate code seeking insight related to the original driving question.


Model Content


MATLAB code will be used to model the reaction and diffusion of pigments in a system. The concentrations of the pigments will produce striping patterns, analogous to what we see in nature from tigers, zebras, or leopards. Tiger stripes will be the focus of the models, which are produced by the pigments eumelanin and pheomelanin.


(Foundational) Instructional Objective


Students will use robust modeling techniques to produce evidence to justify claims about stripe patterns found in nature.

Students will manipulate code to produce useful model results.

Students will identify portions of code that are appropriate for editing.

Students will edit code to pursue evidence they have identified as appropriate for answering a driving question.

Students will use evidence to justify claims about stripe patterns.

Students will relate model results to authentic examples of relevant striping patterns found in nature.

Students will use model results to predict characteristics of the natural system.

Example: “A reduction in reaction rate leads to a loss of stripes. That means a loss of function (LOF) mutation in this gene should produce a mutant phenotype without stripes. Does that exist?”


Eumelanin Trimer

Eumelanin, as a three-monomer oligomer.




Students struggling to access the lesson material will be able to predict the effect of simple manipulations in the code.

Students will accumulate experience manipulating variables that is sufficient to predict the effects of new manipulations.

This experience should lead to comfort in predicting the effects of code changes in unfamiliar code, which leads to access to the foundational objective.


Students unchallenged by the lesson material will be able to create/edit code to produce a new behavior in the model.

Students will identify a current limitation of the model, and attempt to create new code that overcomes that limitation.

This experience is more generative, and should lead to students becoming more comfortable creating novel code behavior, which can apply to new examples.



Lesson Materials


Model Code

  • Each script was written for use in MATLAB, from MathWorks
    • Each script has been adapted to run in Octave, a freely available alternative to MATLAB.
  • model1 - First script, for use on day 1 and day 2
  • TigerStrips1 - Second script, for use on day 3

Structural Models


Day 1 - 45 minute lesson period - Introduction to the model






Day 2 - 45 minute lesson period - Manipulate the model





Day 3 - 45 minute lesson period - Explore a complex model





Extension Resources




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