Darwinian Snails GIRP

This will be the first of two Group Independent Research Projects for the quarter.

Your task

  • Working groups of three or four, your challenge is to use the More Snails environment within Darwinian Snails to conduct a collaborative independent research project. Your group will: (i) ask a question that was not part of the formal Darwinian Snails tutorial , (ii) design and run an experiment to answer it, and (iii) produce a concise coauthored research report.

  • Please watch this 4-minute explainer video. It provides an example of the kind of project I have in mind. I made it for my students in another class a couple of years ago. They were using a somewhat different version of the Darwinian snails interface, but you should have no trouble figuring out how you would conduct the same experiment in the version of the lab you are using.

  • If your group can spot the flaw in the experiment I describe in his video and you can design a better experiment that overcomes this flaw, then you can, if you want to, address the question: Does the strength of selection influence the rate at which a population evolves?

  • Other questions your group can choose to address—see this PDF file for more details:

    • How heritable is shell thickness in Darwinian snails (that is, how much of the variation among individuals is due to difference in genes)?

    • Does the number of founders influence the diversity within a newly-established snail population?

    • Does migration among populations impede local adaptation?

    • How does the amount of genetic variation in a population influence the rate of evolution?

  • It will be helpful to consider ground rules for smoothly functioning groups. As soon as possible, please have a meeting of your group in which you: (1) Discuss your ground rules and upload a completed agreement to the Canvas assignment (only one per group is needed), and (2) Pick the question your group will address.

Replicating your experiments

  • Among the advantages of working with collaborators is that you can run the same experiment many times. That is, you can perform many replicates. Note that something different happens every time you run a SimUText simulation. That means that replicating your experiments is necessary to get a clear idea of whether your predictions are correct.

  • To present your data, you should devise graphs that aggregate the results of your replicates in a useful and informative way. There is an example in the explainer video linked above. I can help you and your collaborators think about ways to aggregate the results for your experiment.

Extracting Data from the Bar Graphs in More Snails

For many of your experimental designs, you will need to record summary data from the bar graphs in More Snails. Here’s how to do so:

  • If you use the pointer tool to click and hold on a bar, a label will appear showing you the height of that bar (proportion of snails in the population it represents):

  • Record this number for all seven bars on the graph (including the bars with heights of zero).

  • Assume all the snails represented by each bar have a shell thickness equal to the midpoint of the bar—that is, 1, 3, 5, 7, 9, 11, or 13.

  • Use these numbers and the proportions to calculate summary statistics, such as the mean and variance. You can do this yourself, or you can use this online calculator or this Excel workbook.

Written Report

Please read the following documents under the Info tab in the main menu:

  • Dr. Herron’s List of Common Prose Errors, Plus some Pet Peeves

  • Citation Format

  • Research Report Format


Your grade will be based on the clarity of your question, the acuity of your scientific reasoning, the design and conduct of your study, and the lucidity of your report. Your grade will not be be based on whether your hypothesis turned out to be right or wrong.

Before uploading your finished report, please be sure to check it against the rubric on the Canvas assignment page.