Part 1: Engage (Anchoring Phenomenon)

Following a sudden environmental disturbance like a severe drought, a previously thriving specialist amphibian population goes extinct, while a pest insect population rapidly increases and a new species slowly diverges. Why do some species thrive while others disappear when their environment changes?

Imagine a lush ecosystem with abundant water and stable temperatures. Several species live here: a Specialist Amphibian that needs high water quality, a Generalist Bird that is adaptable, and a small population of Pest Insects.

Initial Questions:

1. What do you think would happen to these three populations if a severe, prolonged drought struck the area?
2. Which species do you predict would be most affected and why?

Part 2: Explore

You will use the Environmental Change & Extinction Explorer to test your hypotheses. The simulation starts with a stable ecosystem at Year 0.

Instructions:

1. Open the simulation and observe the initial Environment State (Habitat Area, Water Quality, and Temperature).
2. Look at the initial Populations (Specialist, Generalist, Pest, and Diverged) in the chart.
3. Click the “Severe Drought” button to trigger an environmental change event.
4. Let the simulation run for 10 Years. Use the “Pause” button if you need to record data.
5. Record the population sizes and environmental conditions in the table below at Years 0, 5, and 10. You can review the Event Log to see key ecosystem changes.

Data Table: Severe Drought Event

Part 3: Explain

Using the data you collected from your “Severe Drought” simulation run:

1. Water Quality & Extinction: How did the severe drought affect the water quality over the 10-year period? Based on the population data, how did this change directly impact the Specialist Amphibian population?
2. Population Increase: What happened to the Pest Insect population after the drought began? Why do you think this change occurred when other species were struggling?

Part 4: Elaborate/Evaluate (Argumentation & Modeling)

Elaborate

Reset the simulation using the “Reset” button. Let’s test a different environmental disturbance to see if the outcomes are the same.

Instructions:

1. Trigger the “Fertilizer Runoff” or “Deforestation” event.
2. Let the simulation run for another 10 years and monitor the population chart closely.

Analysis:

1. Did the Specialist Amphibian go extinct in this scenario as well? Was the cause the same?
2. Did you observe the emergence of a “Diverged Species”? If so, what environmental conditions seemed to trigger this new species to emerge from the Generalist population?

Evaluate

Construct a scientific argument (Claim, Evidence, Reasoning) addressing the following prompt:

Prompt: How do changes in environmental conditions lead to the extinction of some species, the population increase of others, and the emergence of new species over time?

• Claim: Write a clear statement answering the prompt.
• Evidence: Provide specific data from your simulation runs (e.g., changes in water quality percentages, exact population numbers, specific events) that support your claim. You must include evidence for an extinction, a population increase, and a speciation event.
• Reasoning: Explain the cause-and-effect relationship between the environmental factors (habitat, water quality, temperature) and the ability of individuals in a species to survive and reproduce. Connect your evidence to the scientific principles of adaptation and survival.

Teacher Notes

Estimated Time: 45-60 minutes Materials: Computer with internet access, Simulation URL.

NGSS Alignment: This task is aligned to the performance expectation HS-LS4-5: Evaluate the evidence supporting claims that changes in environmental conditions may result in: (1) increases in the number of individuals of some species, (2) the emergence of new species over time, and (3) the extinction of other species.

Targeted Evidence Statements:

• 1.a.i, ii, iii: Students identify the given claims that changes in environmental conditions may result in increases in individuals, emergence of new species, and extinction. (Addressed in Part 5 CER Claim).
• 2.a.i & ii: Students identify and describe additional evidence including data indicating the change over time in the number of individuals and environmental conditions, as well as environmental factors that determine survival. (Addressed in Parts 2 & 3 Data Collection and Analysis).
• 3.b: Students assess the ability of the given evidence to be used to determine causal or correlational effects between environmental changes and the emergence or extinction of species. (Addressed in Part 4 Elaborate comparison and Part 5 Reasoning).
• 4.a: Students evaluate the degree to which empirical evidence constructs logical arguments identifying causal links between environmental changes and species populations based on survival factors. (Addressed in Part 5 CER Evaluation).

Implementation Tips:

• Encourage students to use the Evaluate Evidence (SEP) tab in the simulation to practice drafting their CER argument using the provided chart data.
• Discuss the difference between causal and correlational effects when reviewing student responses in Part 4.