Lesson 4. Introduction to the Case of Rock Pocket Mice

Sugat Dabholkar, Connor Bain, Philip Woods, Kevin Hall
Biology, Self-directed
40-50 min
High School Advanced Biology (AP)
v3

Overview

In this lesson, students will be introduced to the 'anchoring phenomenon' of rock pocket mice, specifically how the color of the fur coat changed because of the change in the environment where they live. Students will explore a computational model of a population of rock pocket mice and observe changes in the population over time. 

Standards

Next Generation Science Standards
  • Life Science
    • [HS-LS2] Ecosystems: Interactions, Energy, and Dynamics
    • [HS-LS4] Biological Evolution: Unity and Diversity
  • NGSS Crosscutting Concept
    • Patterns
    • Systems
    • Stability and Change
  • NGSS Practice
    • Analyzing Data
    • Using Models
    • Conducting Investigations
Computational Thinking in STEM
  • Data Practices
    • Analyzing Data
    • Manipulating Data
    • Visualizing Data
  • Modeling and Simulation Practices
    • Using Computational Models to Find and Test Solutions
    • Using Computational Models to Understand a Concept
  • Computational Problem Solving Practices
    • Troubleshooting and Debugging
  • Systems Thinking Practices
    • Investigating a Complex System as a Whole
    • Thinking in Levels
    • Understanding the Relationships within a System

Credits

Unit co-designed by Sugat Dabholkar in consultation with teachers at Schurz High School

Acknowledgement

This lesson is based on a curricular unit developed by HHMI (https://www.hhmi.org/biointeractive/making-fittest-natural-selection-and-adaptation).

Activities

  • 1. The curious case of Rock Pocket Mice
  • 2. Introduction to the Computational Model
  • 3. Can we use this model to investigate what might have happened in American Southwest?

Student Directions and Resources


In this lesson, you will study a phenomenon about a population of rock pocket mice. You will explore a computational model of a population these mice and observe changes in the population over time. By the end of the lesson, you'll be able to explain how the color of fur coat of mice changed over time and how it may have been affected by the change in their environment.

1. The curious case of Rock Pocket Mice


The American Southwest is a fantastic place to study rock pocket mice with different fur coat colors. Ancestral pocket mice had light-colored fur coats that blended in with the rocks and sandy soil that was prevalent in the region. This kept the mice hidden from their predators (mainly owls).  Then, a series of volcanic eruptions spewed a river of black lava more than 40 miles long that wove right through the middle of pocket-mouse territory. Lava flows created huge patches of dark rock among the surrounding light-colored sand.

Today there are now two forms of pocket mice:

  • light-colored mice that live on sandy soil
  • dark-colored mice that live on black lava rock

Researchers noticed that rock pocket mice with a dark fur coat were more common on the dark lava flows, whereas the mice with light colored fur coat were more common on the light-colored sand. How might this have happened? 

In orer to investigate this mystery, we're going to investigate this case of pocket mice evolution using computational models.

Let's start by watching a video developed by HHMI Biointeractive about this phenomenon.


Question 1.1

Name at least two things that you found interesting in the video.



Question 1.2

Write down at least two questions that you would like to investigate about the pocket mice in the desert of New Mexico. 

2. Introduction to the Computational Model


Below is a computational model of a population of pocket mice. 

Each clock tick in the model is a mouse-generation and in each generation, male and female mice move around randomly, search for a partner, and reproduce if they find a partner. The fur-coat-color of the mice is a trait that is passed down from one generation to the next.

Play around with the model. It is totally okay if you don't understand everything mentioned in the model. Just explore the model for a few minutes and then try your best to answer the questions below.

 


Question 2.1

There are two fur coat colors, light and dark. Which of these is a homozygous recessive condition?  



Question 2.2

Explain how you figured out the answer the the previous question.



Question 2.3

There are two alleles "A" (dominant) and "a" (recessive). What would the phenotype be of the genotype "Aa"?  



Question 2.4

Explain how you arrived at the answer to the previous question.

3. Can we use this model to investigate what might have happened in American Southwest?



Question 3.1

Based on your investigation using this model, modify your questions that you wrote before. Specifically, you want to try to change your questions so that you could actually investigate them using a computational model like the one you explored in this lesson.



Question 3.2

Explain how you might design some experiments using the model you explored earlier to answer your research questions.