HS-ESS3-3NGSS*ScienceEarth and Space ScienceGrades 9-12
HS-ESS3-3: Spreadsheet Simulations of Resources, Population and Biodiversity
In plain English: HS-ESS3-3 is the NGSS high school performance expectation that asks students to create a computational simulation showing how the management of natural resources, the sustainability of human populations and biodiversity are related. Students build simple spreadsheets and run provided programs linking population, farmland and habitat. It is usually taught in Earth and Space Science or Environmental Science.
Create a computational simulation to illustrate the relationships among management of natural resources, the sustainability of human populations, and biodiversity.
Clarification Statement: Examples of factors that affect the management of natural resources include costs of resource extraction and waste management, per-capita consumption, and the development of new technologies. Examples of factors that affect human sustainability include agricultural efficiency, levels of conservation, and urban planning.
Assessment Boundary: Assessment for computational simulations is limited to using provided multi-parameter programs or constructing simplified spreadsheet calculations.
Next Generation Science Standards · Disciplinary Core Idea: Earth and Human Activity · Official standard
Students create and use simple computational simulations that show how managing natural resources, sustaining a human population and protecting biodiversity are linked. The main model is a spreadsheet of an invented valley: each row is a decade, and simple formulas turn population, food per person, crop yield and urban land per person into farmland needed, habitat remaining and a species index. Students change one input at a time and compare the outputs, then apply the same method to a fishery, a water supply and a landfill.
The NGSS Clarification Statement says: "Examples of factors that affect the management of natural resources include costs of resource extraction and waste management, per-capita consumption, and the development of new technologies. Examples of factors that affect human sustainability include agricultural efficiency, levels of conservation, and urban planning." The Assessment Boundary says: "Assessment for computational simulations is limited to using provided multi-parameter programs or constructing simplified spreadsheet calculations." Every model on this page is a simplified spreadsheet calculation or a provided program with locked formulas, and every data set and parameter is invented for teaching.
Learning Objectives
By the end of this lesson, students will be able to:
Construct a simplified spreadsheet simulation in which each row is calculated from the row before it
Use a provided multi-parameter program to change one input at a time and record how the outputs respond
Explain how per-capita consumption, agricultural efficiency, new technology, urban planning and conservation affect farmland, habitat and food security in a model
Use a model to illustrate how resource management, the sustainability of a human population and biodiversity are related
Identify the simplifications in a model and explain how they limit its conclusions
Prior Knowledge Required
Students should already be comfortable with:
How population growth and per-capita consumption affect Earth's systems MS-ESS3-4
Evaluating designs for maintaining biodiversity and ecosystem services MS-LS2-5
Percent growth, multiplying by a growth factor and reading line graphs
Entering numbers and simple formulas in a spreadsheet (or completing a table by hand)
Write on the board: "A town of 10,000 people grows by 2% every year."
Warm-Up Prompt
"Without a calculator, guess: will the town double in 10 years, 35 years or 100 years? What would you need to write down, year by year, to check your guess? What else would the town need more of as it grows?"
Take guesses, then build the first few rows together on the board: each year's population is last year's times 1.02. Tell students that a spreadsheet can repeat this step for them, and that it takes about 35 years to double. List what the town needs more of (food, water, housing, land): those needs are the links the lesson models.
Direct Instruction15-20 minutes
How a spreadsheet simulation works. Each column holds one quantity and each row is one time step. A formula in each cell computes the new value from the row above and from input cells (the parameters). For example, if cell B2 holds the population and the decade growth factor is 1.3, the next row uses =B2*1.3. Changing one parameter and rerunning the rows is a simulated experiment. Diagram 2 shows the structure of the valley model used in this lesson: inputs, calculated columns and outputs. The model makes one simplification about biodiversity: the species index follows the species-area relationship, a rule used in ecology in which the number of species a habitat supports in the long run is proportional to its area raised to a small power, here 0.25. The examples below use invented numbers.
Per-capita consumption and a water supply
An invented town of 40,000 uses 300 L of water per person per day, and its reservoir can safely supply 15 million L per day. The population grows 2% per year. A spreadsheet row computes demand = population × 300 L.
Result: Year 0 demand = 12 million L/day. Demand = 12 × 1.02n million L first passes 15 million L in year 12. If conservation cuts use to 240 L per person, demand starts at 9.6 million L and first passes the supply in year 23.
Agricultural efficiency and new technology
An invented region has 80,000 people, each needing 0.5 t of grain per year. Farms produce 4.0 t/ha per year. A new crop variety raises the yield to 5.0 t/ha.
Result: Farmland = 80,000 × 0.5 ÷ 4.0 = 10,000 ha, and at 5.0 t/ha it is 8,000 ha. The better technology frees 2,000 ha that can stay as habitat.
Biodiversity: the species-area relationship
An invented forest of 60,000 ha supports about 250 species. Clearing leaves 30,000 ha. The model uses species ∝ (area)0.25.
Result: Species ratio = (30,000 ÷ 60,000)0.25 = 0.50.25 ≈ 0.84, so the forest will support about 250 × 0.84 ≈ 210 species in the long run, about 16% fewer, even though half the area is gone.
Waste management: the life of a landfill
An invented county landfill has room for 2,000,000 t. The county's 100,000 people each send 0.6 t of waste per year. A recycling and composting program would divert 40% of the waste.
Result: Waste = 100,000 × 0.6 = 60,000 t/yr, so the landfill lasts 2,000,000 ÷ 60,000 ≈ 33 years. With 40% diverted, 36,000 t/yr, it lasts about 56 years (population held constant for simplicity).
Urban planning and land for habitat
An invented city will add 90,000 residents. Spread-out housing uses 0.04 ha per person, and compact housing uses 0.01 ha per person.
Result: Spread out: 90,000 × 0.04 = 3,600 ha. Compact: 90,000 × 0.01 = 900 ha. Compact planning leaves 2,700 ha more for farms or habitat.
After each example, ask: "Which cell is the parameter, which is calculated, and which output would a decision-maker watch?" Point out the simplifications (population held constant, one crop, one species rule) and ask how each one could make the model wrong.
Guided Practice15 minutes
Pairs build the valley model (all values invented). Total land is 30,000 ha, of which 12,000 ha can be farmed. The population starts at 40,000 and grows by a factor of 1.3 each decade. Each person needs 0.5 t of grain per year, the yield starts at 4.0 t/ha and rises by 0.4 t/ha each decade, and the city uses 0.03 ha per person. The first five rows are below.
Valley model, baseline run (invented parameters)
Year
Population
Yield (t/ha)
Farmland (ha)
Urban land (ha)
Habitat (ha)
Species index
0
40,000
4.0
5,000
1,200
23,800
377.5
10
52,000
4.4
5,909
1,560
22,531
372.4
20
67,600
4.8
7,042
2,028
20,930
365.6
30
87,880
5.2
8,450
2,636
18,914
356.4
40
114,244
5.6
10,200
3,427
16,372
343.8
Write the formula for each column: population (=B2*1.3), yield (=C2+0.4), farmland (=B3*0.5/C3), urban land (=B3*0.03), habitat (=30000-D3-E3) and species index (=400*(F3/30000)^0.25).
Add the row for year 50. Does the farmland needed pass the 12,000 ha of arable land? (It reaches about 12,376 ha, so the valley can no longer feed itself.) Compare with Diagram 1.
Describe how habitat and the species index change from year 0 to year 50, and explain why the species index falls more slowly than habitat does.
Write one sentence that links resource management, the sustainability of the population and biodiversity using numbers from your model.
Independent Practice10-15 minutes
Each student builds a five-row fishery model (invented parameters). A fish stock starts at 6,000 t in a lake that can hold at most 10,000 t. Each year the stock grows by 0.4 × stock × (1 - stock ÷ 10,000), and then the catch is removed. The spreadsheet formula is =B2+0.4*B2*(1-B2/10000)-C2, with the catch in column C.
Students run the model twice, once with a catch quota of 800 t per year and once with 1,200 t per year, for 5 years each. They graph both runs, state which quota the fishing community can keep using, and explain what happens to fish-eating birds and other species in the lake under each quota. They end by naming one simplification in the model (for example, a fixed catch even when fish are scarce).
Closure5 minutes
Exit ticket: "Name one input you changed today, the output it changed, and whether the change helped the human population, biodiversity, or both. Name one thing the model left out that could change your answer."
Differentiation Strategies
For Struggling Students
Give a partly built spreadsheet with the formulas already in the first row, so students only fill down and change parameters
Start with a two-column model (year and population) before adding farmland and habitat columns
Provide a results table with blank cells for each run, so students record one output at a time
For Advanced Students
Ask students to add a conservation reserve that farmland may not enter, and find the smallest reserve that keeps the species index above 350 through year 50
Have students find, by trial in the fishery model, the largest steady catch the stock can support, and explain why it is not the catch that empties the lake fastest
Ask students to add a cost column (for example, cost per ton of fish rising as the stock falls) and explain how extraction cost could slow overfishing
Assessment Guidance
What to Look For
Check that each row is computed from the row above and from parameter cells, not typed in by hand. Look for simulated experiments that change one input at a time and name the output they compare. Strong explanations connect all three parts of the standard (how the resource is managed, whether people can be sustained, what happens to biodiversity) with numbers from the run, and name at least one simplification. Watch for students who treat model output as a forecast of the future rather than an illustration of relationships.
02
Classroom Activities
3 Activities
1
Build the Valley Model and Test Four Runs
25 minPairs
Pairs finish the valley spreadsheet from Guided Practice, put every parameter in its own labeled cell, and then run four versions of the model to year 50. They compare how each management choice affects food security and biodiversity.
Procedure
Move every parameter (growth factor, food per person, starting yield, yield gain, urban land per person, total land, arable land) into its own cell at the top of the sheet, and point the formulas at those cells.
Run A is the baseline. For runs B, C and D, change only the one parameter listed and record the year-50 outputs.
Graph habitat against year for all four runs on one chart.
Expected Results (from the invented parameters)
Run
Change from baseline
Farmland in year 50 (ha)
Habitat in year 50 (ha)
Species index in year 50
A
None (baseline)
12,376
13,168
325.6
B
Compact city: 0.015 ha per person
12,376
15,396
338.6
C
Faster yield gains: +0.6 t/ha per decade
10,608
14,936
336.0
D
Lower consumption: 0.4 t per person
9,901
15,643
339.9
Discussion Questions
Only runs C and D keep farmland under the 12,000 ha arable limit through year 50. Why does the compact city (run B) save habitat but not solve the food problem?
Run D ends with the most habitat of the four runs. What would lower food consumption per person look like in real life?
The species index changes by only a few percent between runs. Does that mean the choices do not matter? Think about which species are lost first.
Modification for Distance Learning
Share a copy of the spreadsheet with the parameter cells unlocked. Students record a short screen video that changes one parameter and explains the result.
2
Fishing Commons Game
20 minGroups of 4
Each group shares one "lake": a bowl of 40 dried beans (fish). In each round, every fisher catches fish with a paper cup scoop, and then the fish left in the lake double, up to the lake's limit of 40. Each fisher needs at least 3 fish per round to feed a family. Groups play once with no rules and once with a quota they agree on.
Procedure and Safety
Play 5 rounds. After each round, count the fish left, double them (never above 40) and record the catch of each fisher.
Play again with a group rule, for example a quota of 5 fish per fisher per round.
Safety: beans are a choking hazard, so never put them in the mouth, nose or ears, and use paper tokens instead if any student might put small objects in their mouth or has a legume allergy concern. Sweep up spilled beans at once so nobody slips.
Sample Results (invented)
Group 1, no rules: round 1 catches of 8, 7, 9 and 6 (30 fish) left 10, which doubled to 20; round 2 catches took all 20, and the lake was empty from round 3 on. Group 2, quota of 5 each: every round the group caught 20, left 20, and the lake refilled to 40, for 5 full rounds.
Discussion Questions
Over 5 rounds, the quota group caught twice as many fish as the group with no rules. How does a limit on catching raise the total catch?
What would happen in Group 2 if the fish left in the lake grew by only half each round instead of doubling?
Other animals in a real lake also eat these fish. How would an empty lake affect them?
Challenge Variation
Groups turn the game into a spreadsheet: one row per round, with columns for fish at the start, total catch, fish left and fish after regrowth, and they test which quota gives the largest total catch over 10 rounds.
3
Provided Program: One Parameter at a Time
20 minGroups of 3
Groups use a teacher-built version of the valley model with locked formulas and three input sliders or cells. They run a controlled experiment on the population growth factor, holding every other parameter at its baseline value, and write a claim about how growth affects food security and biodiversity.
Sample Output (invented parameters)
Growth factor per decade
First year farmland passes 12,000 ha
Habitat in year 50 (ha)
Species index in year 50
1.2
not by year 50
18,720
355.5
1.3
50
13,168
325.6
1.4
40
5,619
263.1
Tasks
Run the program for each growth factor and fill in the table.
Graph the species index in year 50 against the growth factor.
Write a claim, evidence and reasoning paragraph about the effect of population growth.
Discussion Questions
Raising the growth factor from 1.3 to 1.4 moves the food limit 10 years earlier and cuts year-50 habitat by more than half. Why does a small change in growth rate have such a large effect after five decades?
Why must every other parameter stay fixed during this experiment?
Which management input would you change next to offset faster growth, and what result would you predict?
Modification for Distance Learning
Post the locked spreadsheet online. Each student runs one growth factor, and the class combines the results in a shared table.
03
Diagrams & Visual Aids
2 diagrams
Diagram 1: Farmland Needed Compared with Arable Land (Valley Model)
Output of the invented valley model, drawn to scale. In the baseline run (solid line) farmland needed passes the 12,000 ha of arable land between year 40 and year 50. With faster yield gains from new crop technology (dashed line), farmland stays below the limit through year 50.
Diagram 2: Structure of a Spreadsheet Simulation
Parameters feed formulas that are recalculated in every row, and the outputs show food security and biodiversity. The three boxes below name the relationships HS-ESS3-3 asks students to illustrate.
04
Homework Assignment
~30 min
HS-ESS3-3 Homework: Building and Using Simple Simulations
Directions: All parameters are invented. Use a spreadsheet or complete the tables by hand with a calculator. For each problem, show the formula you used for one row, give the results, and explain what they show about resources, people and biodiversity.
Part 1: Resources and Population (Problems 1-2)
A city of 30,000 people grows 4% per year. Each person uses 7 MWh of electricity per year, and the local power supply is 250,000 MWh per year. (a) Write the formula for next year's demand. (b) Build rows for years 0-5 and find the first year demand exceeds supply. (c) An efficiency program cuts use to 6 MWh per person. Find the new first year demand exceeds supply, and explain how per-capita consumption affects sustainability.
An island has 25,000 people who each need 0.5 t of grain per year, and farms produce 2.5 t/ha. Only 7,000 ha can be farmed. (a) How much farmland is needed now? (b) The population doubles, and new irrigation raises the yield to 3.5 t/ha. How much farmland is needed then? (c) Can the island still feed itself? Name two management changes that could help, and what each would do to the island's forests.
Part 2: Biodiversity in a Model (Problems 3-4)
A model region supports 500 species when all of its habitat remains. The model uses species = 500 × (fraction of habitat left)0.25. (a) Complete a table for 100%, 75%, 50% and 25% of habitat left. (b) How many species are lost going from 100% to 75%, and from 50% to 25%? (c) Explain what the pattern means for protecting the last patches of habitat.
A fish stock of 4,000 t lives in a lake that can hold at most 8,000 t. Each year the stock grows by 0.5 × stock × (1 - stock ÷ 8,000), and then the catch is removed. (a) Build three yearly rows with a catch of 900 t per year. (b) Build three rows with a catch of 1,100 t per year. (c) Which catch can the community keep taking? Explain how the result affects the people who fish and the birds that eat these fish.
Part 3: Management Choices (Problems 5-6)
A landfill has room for 900,000 t, and a town sends it 45,000 t of waste per year. (a) How many years will it last? (b) A composting program diverts 30% of the waste. How many years will it last now? (c) Diverting waste costs $12 per ton, and building a new landfill would cost the equivalent of $30 per ton of space. Use your results to explain how waste management affects the town's costs and its land.
A provided program for an invented coastal plain reports year-30 outputs for three policies. Policy 1 (no change): habitat 11,000 ha, species index 290, food shortfall 0 t. Policy 2 (compact city): habitat 12,500 ha, species index 302, food shortfall 0 t. Policy 3 (convert wetlands to farms that grow grain for export): habitat 8,000 ha, species index 267, food shortfall 0 t. (a) Find the percent change in habitat and in the species index for Policies 2 and 3 compared with Policy 1. (b) Write a recommendation that uses the outputs to relate resource management, the sustainability of the population and biodiversity, and name one simplification in the program.
Rubric
Criterion
Full Credit (2 pts)
Partial Credit (1 pt)
Model Construction
Correct row formula, each row computed from the one before, values correct
Correct formula with one calculation error
Using the Output
Compares runs and cites specific output values as evidence
Reports values without comparing runs
Relationships and Limits
Links resource management, human sustainability and biodiversity, and names a simplification
Links two of the three, or names no simplification
05
Quiz: 20 Questions
Interactive, with answers
Instructions
All models, parameters and data in these questions are invented for practice. A calculator or spreadsheet is helpful. Your score updates as you answer, and Reset quiz clears everything so you or your students can try again.
Multiple choice: pick an option to check it. Short answer: write your answer, then reveal the model answer.
0 of 20 answered · 0 correct
Question 1 of 20 · Multiple Choice
A spreadsheet models a groundwater supply that shrinks by 3% each year. Cell B2 holds this year's supply. Which formula gives next year's supply?
Answer: D
Losing 3% leaves 97% of the supply, so the next value is B2 × 0.97. Choice A subtracts 0.03 of a unit, not 3%. Choice B gives only the amount lost. Choice C models growth of 3% instead of loss.
Question 2 of 20 · Multiple Choice
In a provided program, 120,000 people each need 0.4 t of grain per year, and farms produce 5 t/ha per year. How much farmland does the program report as needed?
Answer: C
Food needed = 120,000 × 0.4 = 48,000 t, and 48,000 ÷ 5 = 9,600 ha. Choice A multiplies by the yield instead of dividing. Choice B divides the population by the yield and skips the food per person. Choice D is the food needed in tonnes, with no division by the yield.
Question 3 of 20 · Multiple Choice
An invented town has 25,000 people who each use 180 L of water per day. Its supply is 5.0 million L per day. What share of the supply does the town use?
Answer: A
Demand = 25,000 × 180 = 4,500,000 L per day, and 4.5 ÷ 5.0 = 0.90, or 90%. Choice B divides the supply by the demand. Choice C misplaces the decimal point (4.5 ÷ 50). Choice D writes 4.5 million as a percent.
Question 4 of 20 · Multiple Choice
A model uses species ∝ (habitat area)0.25. If habitat shrinks to 1/16 of its original area, what fraction of the original species does the model predict in the long run?
Answer: C
(1/16)0.25 is the fourth root of 1/16, which is 1/2. Choice A assumes species fall in direct proportion to area. Choice B takes a square root instead of a fourth root. Choice D is the fraction of habitat lost, not the species left.
Question 5 of 20 · Multiple Choice
In a fishery spreadsheet, next year's stock = stock + 0.5 × stock × (1 - stock ÷ 10,000) - catch. This year the stock is 5,000 t and the catch is 1,000 t. What is next year's stock?
Answer: C
Growth = 0.5 × 5,000 × (1 - 0.5) = 1,250 t, so next year = 5,000 + 1,250 - 1,000 = 5,250 t. Choice A leaves out the growth. Choice B leaves out the catch. Choice D subtracts the growth instead of adding it and leaves out the catch.
Question 6 of 20 · Multiple Choice
A student runs a provided multi-parameter program for 50 years. Which output pattern best shows that the human population is sustainable over the run?
Answer: B
Sustainability in the model means the land and resources can keep supplying what the population needs, so food needed must stay below food available in every row. Choice A describes growth, which may or may not be sustainable. Choice C is a biodiversity cost. Choice D describes one input only.
Question 7 of 20 · Multiple Choice
Between two runs of a provided program, a student raised the yield gain and also lowered urban land per person. Habitat in the final year rose by 2,000 ha. The student concludes that better crops saved 2,000 ha. What is the main problem with this conclusion?
Answer: A
A simulated experiment needs one independent variable per comparison. Because urban land per person also changed, part or all of the gain may come from compact planning. Choice D would add a third change and make the problem worse. Choices B and C are false: the model reports habitat in hectares and is built to compare management choices.
Question 8 of 20 · Multiple Choice
An invented landfill has room for 1,500,000 t and receives 50,000 t per year. A recycling program diverts 25% of the waste. How long will the landfill last with the program?
Answer: B
With 25% diverted, the landfill receives 50,000 × 0.75 = 37,500 t per year, so it lasts 1,500,000 ÷ 37,500 = 40 years. Choice A is the life without the program. Choice C writes the new yearly amount in thousands as years. Choice D divides by the diverted amount (12,500 t) instead of the amount still sent.
Question 9 of 20 · Multiple Choice
In a farm model, a new technology raises crop yield from 3 t/ha to 4 t/ha while the food needed stays the same. How does the farmland needed change?
Answer: A
Farmland = food ÷ yield, so the new farmland is 3/4 of the old, a 25% decrease. Choice B treats the 1 t/ha increase as a share of the old yield (1 ÷ 3). Choice C has the direction backward. Choice D confuses the change in yield with a change in area.
Question 10 of 20 · Multiple Choice
A mining model sets the extraction cost at $40 per ton of ore in year 0 and adds $2 per ton each year as the richest ore is used up. What cost does the model give for year 15?
Answer: C
Cost = 40 + 2 × 15 = $70 per ton. Rising extraction cost is one of the factors that shape how a resource is managed. Choice A adds only one year of increase. Choice B is the increase alone. Choice D multiplies 40 by 15.
Question 11 of 20 · Multiple Choice
A simple spreadsheet computes a species index from habitat area alone. Which real factor that affects biodiversity does this model leave out?
Answer: B
Fragmentation into small, isolated patches can cause more species loss than the area alone predicts, and an area-only model cannot show it. Choice A is the one factor the model does include. Choices C and D are already in the model.
Question 12 of 20 · Multiple Choice
An invented city will add 60,000 residents. Spread-out housing uses 0.03 ha per person and compact housing uses 0.012 ha per person. How much land does compact planning save?
Answer: D
Spread out: 60,000 × 0.03 = 1,800 ha. Compact: 60,000 × 0.012 = 720 ha. The saving is 1,800 - 720 = 1,080 ha. Choices A and B are the two land totals, and choice C adds them.
Question 13 of 20 · Multiple Choice
A provided program reports food produced and food needed (in tonnes) for an invented region. Year 0: 30,000 produced, 24,000 needed. Year 10: 34,000 and 30,000. Year 20: 38,000 and 37,500. Year 30: 42,000 and 46,875. In which year does the region first fall short?
Answer: D
Food needed is below food produced in years 0, 10 and 20 (37,500 < 38,000), but in year 30 it is 46,875 t against 42,000 t, a shortfall of 4,875 t. Choice C is the year the margin is smallest, not a shortfall. Needed food grows by a factor of 1.25 each decade, while production grows by a fixed 4,000 t.
Question 14 of 20 · Multiple Choice
In a farm model, grain consumption per person falls from 0.50 to 0.45 t per year while the population and yield stay the same. By what percent does the farmland needed fall?
Answer: B
Farmland is proportional to food per person, and 0.45 ÷ 0.50 = 0.90, a 10% drop. Choice A treats the 0.05 t change as a percent. Choice C divides the change by the new value (0.05 ÷ 0.45). Choice D is the new consumption written as a percent.
Question 15 of 20 · Short Answer
A town of 20,000 people grows 10% per decade. Each person uses 200 L of water per day, and the supply is 5.0 million L per day. Build rows for years 0, 10, 20 and 30 (population and demand). In which year does demand first exceed supply?
Population: 20,000; 22,000; 24,200; 26,620. Demand (× 200 L): 4.0; 4.4; 4.84; 5.324 million L per day. Demand first exceeds the 5.0 million L supply in year 30. The row formula for population is =B2*1.1, and demand is population × 200.
Question 16 of 20 · Short Answer
A lake fish stock is 8,000 t, and the lake can hold at most 10,000 t. Each year the stock grows by 0.3 × stock × (1 - stock ÷ 10,000). Compute next year's stock for a catch of 400 t and for a catch of 700 t, and explain which quota better supports both the fishing community and the lake's other species.
Growth = 0.3 × 8,000 × 0.2 = 480 t. With a 400 t catch, the stock becomes 8,080 t, and with 700 t it becomes 7,780 t. The 400 t quota is below the growth, so the stock holds steady or grows and can be fished every year, and fish-eating birds and larger fish keep their food supply. The 700 t catch takes more than grows back, so the stock shrinks year after year.
Question 17 of 20 · Short Answer
An invented wetland of 40,000 ha supports 320 species. Draining leaves 12,000 ha. Using species ∝ (area)0.25, about how many species will the remaining wetland support in the long run? What does this suggest about protecting part of the wetland as a reserve?
The area ratio is 12,000 ÷ 40,000 = 0.30, and 0.300.25 ≈ 0.74, so the wetland supports about 320 × 0.74 ≈ 237 species, a loss of about 83. Because species fall more slowly than area, even a modest reserve keeps a large share of species, which makes a protected area a strong management choice. The rule is a simplification: it does not show which species are lost or how they depend on one another.
Question 18 of 20 · Short Answer
You have a provided program with inputs for population growth, food per person, crop yield and urban land per person. Plan a simulated experiment to find out whether improving crop yield or planning a compact city protects more habitat. Name the independent variable, the controlled variables and the output.
Run a baseline, then two test runs. In one, change only the yield gain; in the other, change only urban land per person, keeping population growth and food per person at baseline values in every run. The independent variable is which management input is changed, the controlled variables are all other parameters and the length of the run, and the output is habitat (and the species index) in the final year. Compare each test run with the baseline.
Question 19 of 20 · Short Answer
An invented town of 60,000 people needs 0.5 t of grain per person per year, farms produce 5 t/ha, and the town uses 0.02 ha of urban land per person. The valley has 20,000 ha. (a) How much habitat is left? (b) Yields rise to 6 t/ha and the town adopts compact planning at 0.015 ha per person. How much habitat is left now?
(a) Farmland = 60,000 × 0.5 ÷ 5 = 6,000 ha; urban = 60,000 × 0.02 = 1,200 ha; habitat = 20,000 - 6,000 - 1,200 = 12,800 ha. (b) Farmland = 30,000 ÷ 6 = 5,000 ha; urban = 900 ha; habitat = 14,100 ha, a gain of 1,300 ha from better agricultural efficiency and urban planning.
Question 20 of 20 · Short Answer
A student's spreadsheet lets crop yield rise by 0.5 t/ha every decade forever, starting at 4 t/ha, and concludes that the valley can feed any population. What yield does the model give after 200 years? Critique the model.
After 20 decades the yield is 4 + 0.5 × 20 = 14 t/ha. That is several times today's typical grain yields, and yields cannot rise without limit because plant growth is limited by water, soil nutrients and sunlight. The model needs a ceiling on yield (or a slowing rate of gain). Without it, the simulation hides the real limit that links resource management to the sustainability of the population.
0 of 20 answered · 0 correct
06
Frequently Asked Questions
10 Questions
What does HS-ESS3-3 mean?
HS-ESS3-3 asks students to create a computational simulation that shows how three things are related: how people manage natural resources, whether a human population can be sustained, and biodiversity. In practice, students build a simple spreadsheet model or use a provided program, change its inputs and explain the results. The code means High School, Earth and Space Science, core idea 3 (Earth and Human Activity), performance expectation 3.
What is the assessment boundary for HS-ESS3-3?
Assessment is limited to using provided multi-parameter programs or constructing simplified spreadsheet calculations. Students are not expected to write computer code or build complex ecological models, and every model on this page stays within that limit.
Do students need to know how to code for HS-ESS3-3?
No. A spreadsheet is enough: each row is one time step and each cell formula is a short calculation. Students who have never used a spreadsheet can complete the same model as a table with a calculator, one row at a time.
What is a multi-parameter program?
It is a ready-made simulation with several inputs (parameters) that students can change, such as population growth, food per person and crop yield, and outputs they can compare. The formulas are fixed, so students focus on designing runs and interpreting results. A teacher-built spreadsheet with locked formulas works well.
Is HS-ESS3-3 taught in environmental science or Earth science?
It is usually taught in Earth and Space Science or Environmental Science, and it connects closely to high school life science standards on biodiversity and human impacts. It is a good place to practice spreadsheet skills that students also use in math courses.
What is the species-area relationship used in these models?
It is a pattern observed in ecology: larger areas of habitat support more species, roughly in proportion to the area raised to a small power, often between about 0.15 and 0.35. The models on this page use 0.25. It is a simplification: it predicts a number of species, not which ones, and it treats every hectare as equal.
How do you teach spreadsheet modeling in a science class?
Build the first two rows together by hand, then show how one formula filled down repeats the step. Keep parameters in labeled cells so students can change them without editing formulas. Ask students to predict each run's result before they change a parameter.
Why do simple models give different answers from real ecosystems?
Simple models leave out many real factors, such as weather, disease, trade, changing diets and how species depend on each other. Their purpose here is to illustrate relationships, not to forecast exact numbers. Asking students to name what a model leaves out is part of the practice.
What safety steps apply to the fishing game?
Dried beans are a choking hazard, so students must never put them in their mouths, noses or ears. Use paper tokens for younger students or if a legume allergy is a concern, and sweep up spilled beans right away so nobody slips.
What comes before and after HS-ESS3-3?
It builds on MS-ESS3-4, where students argue how population growth and per-capita consumption affect Earth's systems. Next, HS-ESS3-6 uses a computational representation of how human activity is changing the relationships among Earth's systems, and HS-LS4-6 asks students to create or revise a simulation to test a solution for protecting biodiversity.
07
Related Standards
6 standards
These standards connect to HS-ESS3-3: prerequisites to review first, parallel standards at the same level, and next steps that build on it.
Before this lesson
MS-ESS3-4Prerequisite
Argue how population growth and per-capita consumption affect Earth's systems
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