Objective: 

Students will model an ecosystem using variables to represent predator-prey relationships, focusing on the movement of matter among plants, animals, and decomposers in the environment.

Materials Needed: 

• Index cards,

• Tokens (representing prey)

• Dice (to represent predator actions)

Steps:

• Introduction: 

  • The teacher introduces the concept of ecosystems and explains how matter moves between plants, animals, and decomposers. 

  • Students will simulate a predator-prey ecosystem using tokens as prey and dice to represent predator actions.

• Activity: 

  • Students form groups and assign roles: predators, prey, and decomposers. 

  • The predators "hunt" prey by rolling dice to determine if they capture a prey token. 

  • Each group tracks the number of prey caught and sets a "score" variable for predators, starting at 0, which increments by 1 with each capture. 

  • A second variable, "numberOfLives" for the prey, starts at 3 and decrements by 1 with each capture. The game ends when "numberOfLives" equals 0.

• Discussion: 

  • Students reflect on how the simulation shows the movement of matter in ecosystems, discussing how plants, animals, and decomposers interact.

Equity and Access: 

Provide pre-written score sheets and examples of gameplay for students needing additional support. Pair mixed-ability students for collaboration.

Real-World Connection: 

Relate the activity to real ecosystems, such as predator-prey relationships in the wild, and discuss how human activity can impact these systems. Discuss how the game created could be coded to exist in a virtual environment, with “numberOfLives” as a variable.

CS Practice(s): 

• Developing and Using Abstractions: Students use tokens and variables to represent elements in an ecosystem.

Standard(s): 

• CA NGSS 5-LS2-1

• CA CS 3-5.AP.11

Objective:

Students will use Scratch or another coding platform to create a predator-prey game that models how matter moves through an ecosystem, using variables to track predator captures and prey survival.

Materials Needed: 

• Computers or tablets

Steps:

• Introduction: 

  • The teacher introduces the class to ecosystems, focusing on how matter cycles through plants, animals, and decomposers. 

  • The teacher then explains that students will create a game in Scratch to model predator-prey interactions, using variables to track scores and lives.

• Activity: 

  • In pairs, students code a game where a predator sprite chases prey. 

  • They declare a "score" variable to start at 0, which increments each time the predator captures a prey, and a "numberOfLives" variable for the prey, starting at 3 and decrementing by 1 with each capture. 

  • When the "numberOfLives" variable reaches 0, the game ends. 

  • Students test and refine their programs, ensuring the variables work as expected to represent predator-prey interactions.

• Presentation: 

  • Students share their games with other groups, explaining how the variables track the ecosystem’s balance and demonstrating how the game models the movement of matter in an ecosystem.

Equity and Access: 

Provide a pre-built coding template for students who need extra guidance and use mixed-ability pairs for peer learning.

Real-World Connection: 

Discuss how simulations and models are used in wildlife conservation to track predator-prey dynamics and ecosystem health.

CS Practice(s): 

• Creating Computational Artifacts: Students create and use variables to store and modify data, tracking the predator-prey interactions. 

• Testing and Refining Computational Artifacts: Students debug and improve their code to ensure accurate gameplay.

Standard(s): 

• CA NGSS 5-LS2-1

• CA CS 3-5.AP.11