Lesson 2. Using Blocks to Model Ecosystems

Sugat Dabholkar, Connor Bain, Philip Woods, Kevin Hall
Biology, Self-directed
45 minutes
High School Advanced Biology (AP)
v9

Overview

This unit introduces computational thinking practices which include data practices, modeling and simulation practices, computational problem solving practices, and systems thinking practices. These practices are introduced to students in the context of a biology unit about ecology. 

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

CODAP is a computational tool for data analysis and representation developed and built by The Concord Consortium at https://codap.concord.org/  

The first four lessons are based on a Howard Hughes Medical Institute (HHMI) Biointeractive (https://www.hhmi.org/biointeractive/pocket-mouse-evolution)

Lesson 5 is based on the lesson Evolution in Action: The Galápagos Finches Authored by Paul Strode for Howard Hughes Medical Institute based on data collected by Peter and Rosemary Grant, Princeton University.

This work is supported by the National Science Foundation (grants CNS-1138461, CNS-1441041 and DRL-1020101) and the Spencer Foundation (grant 201600069). Any opinions, findings, conclusions, and/or recommendations are those of the investigators and do not necessarily reflect the views of the funding organizations.

Activities

  • 1. Modeling Ecosystems
  • 2. Making Computational Models of Ecosystems
  • 3. Making the Model More Realistic

Student Directions and Resources


In this lesson, you will build and explore computational models of living systems. A special type of scientist called computational biologists, use computational models to study biological systems.

This unit focuses on prey-predator interactions in an ecosystem. It uses two computational modeling environments - NetTango and NetLogo.

NetTango is a block-based coding environment. It uses blocks to create a code for a computer program to perform certain tasks.  

NetLogo is text-based coding environment. It uses text to write code for creating computational models.

As you spend your time learning about how to construct computational models of prey-predator ecosystems, you will learn a bit about coding using blocks as well as text.

1. Modeling Ecosystems


Isle Royale

Ecosystems are often difficult to understand because they usually include interactions between a large number of species. Isle Royale is different. It is a relatively simple island ecosystem, located 24 km from the shore of Canada in Lake Superior.

 

While there are many types of small animals on the island, and almost 20 types of mammals, only two species of the mammals that live on the island are relatively large. These are the wolves and the moose. On this island, wolves are the only predator of moose, and moose are essentially the only food for wolves.

  

To understand nature, it helps to observe an ecosystem where human impact is limited. On Isle Royale, there are no towns and people do not hunt wolves or moose or cut down any of the forests. It is a very rare place on the planet where wolves, their prey, and the plants that support the prey are all left unharvested by humans. Isle Royale is remarkable because nature runs wild there.

Your challenge over the course of the next few days will be to build a scientific model that can realistically simulate the interactions of wolves and moose on Isle Royale, in order to help make predictions about how these two populations may change over time. 

 


Question 1.1

Thinking about this community of wolves and moose in Isle Royale, do you believe that the size of the wolf population will change from one day to the next?

  Yes
  No


Question 1.2

Do you believe that the size of the wolf population will change from one month to the next?

  Yes
  No


Question 1.3

Do you believe that the size of the wolf population will change over the course of 30 years?

  Yes
  No


Question 1.4

Since wolves can’t typically migrate on or off the island, what other factors might cause the size of the wolf population to change from year to year?



Question 1.5

Describe what may cause changes in the population of wolves and moose over time.

2. Making Computational Models of Ecosystems


Let's start with building a simple model.

  1. Scroll down the page and interact with the setup and go (play) button.
  2. Drag blocks over to tell the wolves how to behave. Anytime you make changes click on the "recompile" button followed by setup and go (play). 
  3. You can use blocks multiple times.
  4. Blocks can be dragged to the trash to take them out of the code.

Try the following challenges:

  1. Get the wolf to move around the field.
  2. Get the wolf to move around the field more realistically (hint: think about how wolves might move in real life)
  3. Get the wolf to draw a dashed line or another pattern.


Question 2.1

Which blocks did you use to make the wolf move around the field? Choose all that apply.

  wolf actions
  wolf meets moose
  forward
  left
  right
  pen down
  pen up


Question 2.2

Does the wolf look like it’s walking around the whole field or is it just going in a straight line or circles? If the moose aren't moving does the wolf get to all of them over time? Choose all that apply. Hint: Use the pen down block to have the wolf mark it's path.

  The wolf is moving around in circles.
  The wolf is moving in a straight line.
  The wolf is only moving around on some of the field.
  The wolf is moving around the whole field realistically.
  The wolf isn't moving.


Question 2.3

After you have gotten your wolf moving, spend time trying to figure out the best block combination needed to get more realistic wolf movement. Try changing the numbers found in some of the blocks. What combination of blocks did you use to get realistic movement?



Question 2.4

What blocks did you use to get the wolf to draw a dashed line?

  wolf actions
  wolf meets moose
  forward
  left
  right
  pen down
  pen up
  hatch
  die
  ask nearby moose
  chance


Question 2.5

If you could, what other types of behavior blocks would you add to make a more realistic wolf and moose predator/prey model?

3. Making the Model More Realistic


The poor defenseless moose should be allowed to move as well! Start by setting up realistic movement for both wolves and moose and then move on from there.

Try the following challenges:

  1. Get wolves and moose move around the field in a realistic way.
  2. Make a wolf eat a moose when it runs into one.
  3. Make the moose slowly multiply.
  4. Come up with a challenge of your own!


Question 3.1

Which blocks did you use to make the wolf eat the moose? Choose all that apply.

  wolf actions
  wolf meets moose
  forward
  left
  right
  pen down
  pen up
  hatch
  die
  ask nearby moose
  chance


Question 3.2

Which blocks did you use to make the moose multiply? Choose all that apply.

  wolf actions
  wolf meets moose
  forward
  left
  right
  pen down
  pen up
  hatch
  die
  ask nearby moose
  chance


Question 3.3

Which block(s) did you use to slow down the moose reproduction?

  wolf actions
  wolf meets moose
  forward
  left
  right
  pen down
  pen up
  hatch
  die
  ask nearby moose
  chance


Question 3.4

What other behavior blocks could you add to this model to help make it more realistic?



Question 3.5

Describe the challenge that you created and how you completed it.