PhET Activity for MS-LS1-5: Natural Selection

DIRECTIONS:
1. Click on the 'Intro' button on the main screen to enter the simulation.
2. Click the 'Add a Mate' button in the center of the environment to start a population.
3. Press the Play button at the bottom right to start the simulation and observe the rabbits.
4. Press the Pause button to stop the simulation.
5. Explore the other controls like the environment toggle (sun/snowflake icon) at the top right and the graph options, but do not add mutations or environmental factors yet.
Spend 2-3 minutes exploring the simulation. Start and stop time, add a mate, and see what the different buttons do. When you are finished exploring, press the orange Reset button to prepare for the next slide.

QUESTION: Are you acquainted with the tools in this simulation?

DIRECTIONS:
1. Ensure the simulation has been reset. You should be in the 'Intro' tab.
2. Click 'Add a Mate' in the center of the environment.
3. Press the Play button and let the simulation run for 5 generations.
4. Pause the simulation.

QUESTION: Without any predators or food limits, what happens to the rabbit population?

DIRECTIONS:
1. Press the orange Reset button.
2. Click 'Add a Mate'.
3. Let the simulation run for one generation and then pause it.
4. Click the 'Fur' button under the 'Add Mutation' panel on the right. A brown rabbit will appear.
5. Press Play and let the simulation run for 4-5 more generations.

QUESTION: A ___ is a change in genetic material that introduces a new ___ into the population.

(a)  

DIRECTIONS:
1. Pause the simulation.
2. In the 'Environmental Factors' panel on the right, check the box next to 'Wolves'.
3. Press Play and observe for several generations.

QUESTION: In the Equator environment, the presence of wolves makes the brown fur trait (a)   .

DIRECTIONS:
1. Let the simulation from the previous slide continue running until the population of white rabbits is zero or close to zero.
2. Pause the simulation.

QUESTION: Explain why the population of brown rabbits increased while the population of white rabbits decreased after wolves were introduced.

DIRECTIONS:
1. Press the orange Reset button.
2. Click 'Add a Mate'.
3. Click the 'Fur' button to add the brown fur mutation.
4. Let the simulation run for 2-3 generations to establish both populations, then pause.
5. Click the snowflake icon in the top right to switch to the 'Arctic' environment.
6. Check the 'Wolves' box.
7. Press Play.

QUESTION: After switching to the Arctic environment with wolves, what will most likely happen to the population of brown rabbits?

DIRECTIONS:
1. Let the simulation from the previous slide run until the brown rabbit population is very small or gone.
2. Pause the simulation and examine the graph.

QUESTION: In the Arctic environment, the ___ fur trait is disadvantageous, meaning it leads to a lower ___ rate when predators are present.

(a)  

DIRECTIONS:
1. Press the orange Reset button.
2. Click 'Add a Mate'.
3. In the 'Add Mutation' panel, click the selector on the 'Fur' mutation to choose 'recessive'.
4. Let the simulation run for 5-6 generations.
5. Click the 'Pedigree' radio button to the right of the graph.
6. Click on a brown rabbit (which now has the recessive trait 'ff') to view its family tree.

QUESTION: If a rabbit displays a recessive trait (like brown fur, 'ff'), what must be true about the alleles of its parents?

DIRECTIONS:
1. Press the orange Reset button.
2. Click 'Add a Mate'.
3. In the 'Environmental Factors' panel, check the box for 'Limited Food'.
4. Press Play and observe the population graph for at least 15 generations.

QUESTION: Limited food prevents the population from growing infinitely. This maximum population size that the environment can sustain is known as its (a)   .

DIRECTIONS:
1. Press the orange Reset button.
2. Click the 'Lab' tab at the bottom of the simulation screen.
3. Click 'Add a Mate'.

QUESTION: In the 'Lab' environment, you can study the influence of multiple genetic factors at once. Besides fur color, what is another genetic trait you can introduce to the rabbit population?