D2.Geo.12.6-8: How Changes in Where People Live Change the Land: California's Central Valley
In plain English: D2.Geo.12.6-8 is the C3 Framework geography indicator for grades 6-8 that asks students to explain how global changes in where people live, such as the shift of people into cities and their growing suburbs, change the way land is used in particular places, for example when farms become neighborhoods. It is usually taught in middle school geography or world studies.
Explain how global changes in population distribution patterns affect changes in land use in particular places.
C3 Framework for Social Studies (NCSS) · Dimension 2: Applying Disciplinary Concepts and Tools · Discipline: Geography · Global Interconnections: Changing Spatial Patterns · Official standard
D2.Geo.12.6-8 asks students to explain how global changes in population distribution patterns lead to changes in land use in particular places. Population distribution is the pattern of where people live across an area: crowded in cities, spread out in the countryside, or somewhere between. Land use is what people do with land, such as farming, grazing animals, building homes or running businesses. The big global change of the last 60 years is urbanization, the growing share of people who live in cities and the towns around them; since about 2007, more than half of the world's people have lived in urban areas.
The particular place in this lesson is the Central Valley of California, one of the country's most important farming regions, which lies just east of the crowded San Francisco Bay Area. Students use World Bank figures on world urbanization, U.S. Census Bureau county populations and migration estimates, and one short U.S. Geological Survey source on how the valley's land cover changed from 1973 to 2000. They build a cause-and-effect chain: a global or regional change in where people live, then a change in a particular place's population, then a change in how its land is used.
Learning Objectives
By the end of this lesson, students will be able to:
Describe a global change in population distribution, using data on the share of people living in urban areas.
Read census tables and a county map to describe how population changed in a particular place.
Explain, with evidence from a source, how population growth changed land use in that place, including effects that ripple outward to other land.
Apply the population-to-land-use chain to a new place and predict a likely change.
Prior Knowledge Required
Students should already be comfortable with:
Analyzing how human-environment relationships extend or contract settlement patterns D2.Geo.8.6-8
Integrating information from maps and tables with a written source RH.6-8.7
Computing a difference, a percent and a percent change from two numbers
"Think of a place near you where you have seen new houses, stores or roads built on land that used to be fields, woods or empty lots. What do you think caused the change? Where did the people who live there now come from?"
List three or four answers. Ask students to sort the causes into two groups: more people (people moving in, families growing) and other reasons (a new road, a business moving). Explain that today's lesson follows the first group: when the pattern of where people live changes, the land changes too.
Direct Instruction15 minutes
Part 1: Words to know. An urban area is a city and the built-up area around it; a suburb is a community at the edge of a city, often where many people live and travel to jobs elsewhere. Migration is moving from one place to live in another; domestic migration means moving within the same country, and international migration means moving from another country. Land cover is what covers the ground (crops, grass, buildings, water); land use is what people use it for. A square kilometer (km²) is the area of a square 1 kilometer on each side, about 0.39 square mile. On Diagram 2, an ecoregion is a large area with similar natural features (here, the flat floor of the Central Valley); developed land is land covered by buildings, roads and parking lots; and grassland/shrubland is land covered by grasses or low bushes, much of it used for grazing animals.
Part 2: From the world to one valley. Show Table 1: the global change. Then point to the Bay Area and the Central Valley on Diagram 1 and show Tables 2 and 3: the regional change. Finally, show the right side of Diagram 2: the change in land.
Table 1. Share of people living in urban areas (real data: World Bank, World Development Indicators, indicator SP.URB.TOTL.IN.ZS, based on United Nations World Urbanization Prospects estimates; updated July 2026; licensed CC BY 4.0)
Year
World
United States
1960
34.2%
70.0%
1980
39.5%
73.8%
2000
46.8%
79.1%
2024
57.6%
80.1%
Table 2. County population, 1950-2024 (real data: U.S. Census Bureau; 1950-1990 from the 1990 census report CPH-2-6, Table 3; 2024 from the Vintage 2024 estimates for July 1, 2024)
County
Where
1950
1970
1990
2024
San Joaquin
Central Valley
200,750
291,073
480,628
816,108
Stanislaus
Central Valley
127,231
194,506
370,522
556,972
Santa Clara
Bay Area
290,547
1,065,313
1,497,577
1,926,325
Alameda
Bay Area
740,315
1,071,446
1,279,182
1,649,060
Table 3. People gained or lost by migration, April 2020 to July 2024 (real data: U.S. Census Bureau, Vintage 2024 county estimates; a minus sign means more people moved out than moved in)
County
Domestic migration (within the U.S.)
International migration
San Joaquin
+5,618
+18,994
Stanislaus
-12,703
+8,347
Santa Clara
-154,647
+118,351
Alameda
-129,127
+73,474
San Francisco
-84,404
+35,338
Reading the global change
Use Table 1. By how many percentage points did the world's urban share rise from 1960 to 2024? (A percentage point is the plain difference between two percents.)
Result: 57.6 - 34.2 = 23.4 percentage points. A much larger part of the world's population now lives in urban areas.
Growth in one county
Use Table 2. About how many times as many people lived in Stanislaus County in 2024 as in 1950?
Result: 556,972 ÷ 127,231 ≈ 4.4, so more than 4 times as many people. Each of those people needs a place to live, work and shop.
Sizing the change in land
Source 1 says the Central Valley gained 1,129 km² of developed land from 1973 to 2000. The city of San Jose covers about 461 km² of land (Census Gazetteer). About how many San Joses is that?
Result: 1,129 ÷ 461 ≈ 2.45, so the new developed land was about 2½ times the land area of San Jose.
Reading the migration table
Use Table 3. What was Santa Clara County's net migration (domestic plus international) from 2020 to 2024?
Result: -154,647 + 118,351 = -36,296. Many more people moved from Santa Clara to other parts of the United States than moved in from them, and arrivals from other countries made up most, but not all, of that loss.
Guided Practice15 minutes
Read Source 1 together. It comes from the U.S. Geological Survey (USGS), the government science agency that studied land change across the West using satellite images from 1973 to 2000. Words to know: an ecoregion is a large area with similar natural features, here the flat floor of the Central Valley; terrain is the shape of the land; fertile soil is good for growing crops; in cultivation means being farmed; commodities are goods that are bought and sold; grassland/shrubland is land covered by grasses or low bushes, much of it used for grazing (feeding animals on grass); developed land is land covered by buildings, roads and parking lots; adjacent means next to; the periphery is the outer edge. Paragraph numbers count only the paragraphs shown.
1The Central California Valley Ecoregion accounts for more than half of California’s agricultural production value and is one of the most important agricultural regions in the country, with flat terrain, fertile soils, a favorable climate, and nearly 70 percent of its land in cultivation [...]. Commodities produced in the region include milk and dairy, cattle and calves, cotton, almonds, citrus, and grapes, among others [...]. The Central California Valley Ecoregion is also home to nearly 5 million people spread throughout the region, including the major cities of Sacramento (state capital), Fresno, Bakersfield, and Stockton, California [...].
[...]
2The largest change in any one land-cover class between 1973 and 2000 was the loss of 1,782 km² of grassland/shrubland (20.2 percent of the area it occupied in 1973 [...]). The second largest change was the addition of 1,129 km² of developed land cover (an increase of 37.7 percent), increasing from 6.5 to 9.0 percent of the ecoregion area. Agricultural lands, which accounted for more than 70 percent of the Central California Valley Ecoregion, remained relatively stable throughout the study period with a net increase of 358 km² (1.1 percent increase).
[...]
3[...] As urban areas expand, agricultural land is converted to developed land. In many instances, farmland converts to grassland/shrubland before being developed. [...]
4A major driver of change in the ecoregion is population growth. Population growth in the San Francisco Bay area and Los Angeles, as well as in the Central Valley itself, has resulted in a high demand for land for urban uses [...]. Within the ecoregion, as new development adjacent to existing urban areas converts agricultural land to homes, businesses, and other urban uses, farms are relocating to the ecoregion periphery and then converting traditional grazing lands (grassland/shrubland) into new agricultural uses.
[...]
5As California’s population continues to increase, additional demands will be placed on the Central California Valley Ecoregion to support people and the agricultural complex they depend on, which will result in the continued evolution of the nation’s most diverse agricultural region.
Benjamin M. Sleeter, U.S. Geological Survey, Status and Trends of Land Change in the Western United States, 1973 to 2000: Central California Valley Ecoregion, selected paragraphs (Source 1) (2012). US government work (17 U.S.C. 105). Source text.
Find the place's strengths. In paragraph 1, students underline the natural reasons the valley is good farmland and circle the cities named.
Find the three numbers. In paragraph 2, students find how much land each class lost or gained and check them against the right side of Diagram 2.
Find the cause. Students box the sentence in paragraph 4 that names the driver of change, and list the three places where Source 1 says population grew.
Start the chain. As a class, fill in the first two links on the board: "Population grows in ___ and in the valley itself" then "People need land for ___." Students finish the chain in Independent Practice.
Independent Practice15-20 minutes
Finish the chain and explain it. Students write a paragraph of 5-7 sentences that explains how changes in where people live have changed land use in the Central Valley. The paragraph must include one number from Table 1 or Table 2, one fact from Table 3 or Diagram 1, and one quotation from Source 1, cited by paragraph. It must also explain one change that happened on land that did not itself become houses.
Check yourself. A strong chain has four links: a change in population distribution (global or regional), a change in the particular place's population, a change in land use, and a further effect on other land.
Closure10 minutes
Exit ticket. "Name one particular place, real or invented, where you think more people will mean a change in land use. What land use will grow, and what land use might shrink?"
Teacher note on the data. The county figures for 2024 and the migration figures are Census Bureau estimates, which are revised each year; the land-cover figures are USGS estimates from satellite samples for 1973 to 2000, the most recent period in that study. Migration is described in numbers only: the data do not say why people moved, so treat reasons such as housing costs or jobs as possibilities students could research, not as facts from these sources. The lesson does not judge local land-use or housing decisions; if students raise them, present them as questions on which residents disagree.
Differentiation Strategies
For Struggling Students
Give a chain frame with four boxes: "More people in ___" then "Need for ___" then "Farms or fields become ___" then "So ___ changes too."
Read Source 1, paragraphs 3 and 4, aloud and let students work with those two paragraphs only.
Provide Table 2 with the growth from 1990 to 2024 already worked out for one county as a model.
For Advanced Students
Use Tables 2 and 3 to argue whether the Central Valley's growth after 2020 came more from domestic migration or from international migration and births, and explain what extra data would settle it.
Source 1 describes 1973 to 2000. Find a newer USGS or Census source on land or population in San Joaquin County and test whether the pattern continued.
Compare the Central Valley with a fast-growing urban region in another country, using an official source, and explain one similarity and one difference in how land use changed.
Assessment Guidance
What to Look For
Strong answers link a change in where people live to a change in a particular place's land, with a number for the population change and a source quotation for the land change. The best answers also follow the ripple: farms that move to the valley's edges and turn grazing land into cropland. Watch for answers that confuse population size with population distribution, that read a percent increase as percentage points, or that state reasons for migration the data do not show.
02
Classroom Activities
3 Activities
1
Chain Cards: The Ashgrove Valley
15 minPairs
The Ashgrove Valley is an invented farming valley, made up for this activity. Pairs put 9 cards in cause-and-effect order, from a change far away to a change on the land, then glue or draw arrows between them. Some cards can branch.
The 9 Cards (invented)
Orchards on the north side of Ashgrove town are sold to builders.
Jobs in Rivermouth, a big city two hours away, grow fast, and homes there become hard to find.
A new road and two schools are built on the north side of town.
Ashgrove's population grows from 40,000 to 64,000 in twenty years.
Around the world, more and more people move to cities and the towns near them.
A dairy farmer whose land was sold buys pasture in the hills and plows part of it for feed crops.
Many Rivermouth families move to Ashgrove, where homes cost less, and drive or ride the train to work.
The hills have less open pasture for grazing sheep.
A housing development of 900 homes is built where the orchards were.
Answer Key
One good order: E, B, G, D, A, I, C, then the branch F, H. Global change (E) and regional change (B, G) come first; the place's population grows (D); land use near town changes (A, I, C); and the ripple reaches land farther away (F, H). Ashgrove grew by 24,000 people, or 60%. Accept orders that keep causes before effects and that students can explain.
Discussion
Ask: which card is the global change, and which is the particular place? Which cards would a satellite photo show, and which would only a census show? Which change happened on land that never became houses?
2
Graph the Growth
20 minPairs
Pairs turn Table 2 into a line graph with one line per county, then measure how fast each county grew and compare the Bay Area with the Central Valley.
Tasks
On graph paper, draw years 1950-2024 across the bottom and population (0 to 2,000,000) up the side. Plot and connect the four points for each county, using a different color for each.
For each county, find the percent change from 1990 to 2024: (2024 - 1990) ÷ 1990 × 100.
Check your answers against Diagram 1. Which two counties grew fastest after 1990, and where are they?
Write two sentences: one about which counties have the most people, and one about which grew fastest after 1990.
Answer Key
2. San Joaquin: (816,108 - 480,628) ÷ 480,628 ≈ 69.8%. Stanislaus: ≈ 50.3%. Santa Clara: ≈ 28.6%. Alameda: ≈ 28.9%. 3. San Joaquin and Stanislaus, both in the Central Valley. 4. Sample: "The Bay Area counties have far more people, but after 1990 the two Central Valley counties grew faster."
3
Land-Use Grid: Four Rounds of Growth
15 minGroups of 3
Each group gets an invented 6-by-6 grid map of the Brindle Plain: 4 town squares in the middle, 20 farm squares around the town, and 12 grazing squares at the outer edge. In each of 4 rounds, population grows and the town takes over 2 farm squares next to it. A farm that loses its square moves to the edge and turns one grazing square into farmland.
Tasks
Play 4 rounds, coloring the grid after each round. Record the number of town, farm and grazing squares in a table.
Compare the start and the end. Which kind of land shrank the most? Which hardly changed?
Write one sentence comparing your grid with Diagram 2.
Answer Key
Each round adds 2 town squares, removes 2 farm squares near town and adds 2 farm squares at the edge, so the farm total stays the same while 2 grazing squares are lost. After 4 rounds: town 4 + 8 = 12, farm 20, grazing 12 - 8 = 4, still 36 squares in all. Grazing land shrank the most; farmland stayed the same in total but moved outward. The grid is a simplified model of the pattern on the right side of Diagram 2.
03
Diagrams & Visual Aids
2 diagrams
Diagram 1: Population Change by County, 1990 to 2024
Real data: U.S. Census Bureau, 1990 census counts (report CPH-2-6, Table 3) and Vintage 2024 estimates for July 1, 2024. Each county is shaded by its percent change in population; labels show the change for ten counties. County outlines come from the Census Bureau's 2023 cartographic boundary file (1:20,000,000), so coastlines are simplified, and counties at the edges are cut off by the frame. City points are Census Gazetteer coordinates. San Francisco County, the small county at the tip of the peninsula, is shaded (+14%, under 20%) but has no label or city point because it is too small to label at this scale; its migration figures are in Table 3. The horizontal scale is adjusted for latitude so the shapes look true.
Diagram 2: From the Whole World to One Valley
Left: the share of the world's people living in urban areas, 1960-2024 (World Bank, World Development Indicators, based on United Nations estimates; data licensed CC BY 4.0); the dashed line marks one half. Right: net change in three land-cover classes in the Central California Valley Ecoregion, 1973 to 2000, in square kilometers (U.S. Geological Survey, Professional Paper 1794-A, chapter 17). Bars and line are drawn to scale.
04
Homework Assignment
~30 min
D2.Geo.12.6-8 Homework: Lunmark County
Directions: Lunmark County and Port Halvik are invented places, made up for this homework, and all their numbers are invented. Read the profile, then answer the problems in complete sentences and show your work.
Lunmark County (invented): a farming county of orchards and dairy farms, about an hour by highway from Port Halvik, a large and fast-growing port city where homes have become very expensive. Lunmark had 85,000 people in 1995 and 153,000 in 2025. Its land in 1995: 120,000 acres of farmland, 6,000 acres of developed land and 40,000 acres of grazing land. In 2025: 112,000 acres of farmland, 14,500 acres of developed land and 39,500 acres of grazing land. Many new residents drive to jobs in Port Halvik.
Part 1: Work with the Numbers (Problems 1-3)
By what percent did Lunmark's population grow from 1995 to 2025?
How many acres did each kind of land gain or lose from 1995 to 2025? Which kind of land grew the most, and by about what percent?
Add up Lunmark's land in 1995 and in 2025. Do the totals match? Explain why they should.
Part 2: Explain and Compare (Problems 4-6)
Write a four-link chain for Lunmark County: a change in where people live, a change in Lunmark's population, a change in land use, and one further effect.
In the Central Valley, Source 1, paragraph 2, says farmland stayed about the same from 1973 to 2000. In Lunmark, farmland shrank. Using Source 1, paragraph 4, explain one reason the two places could differ.
Write a paragraph of 5-7 sentences predicting how Lunmark's land use might change by 2055 if Port Halvik keeps growing. Use at least two numbers from the profile and one idea from Source 1.
Rubric
Criterion
Full Credit (2 pts)
Partial Credit (1 pt)
No Credit (0 pts)
Calculations
Percent growth, land changes and totals all correct with work shown
One or two errors
Mostly incorrect or missing
Cause-and-Effect Chain
Four clear links from a change in where people live to an effect on land
Two or three links, or links out of order
No chain
Use of Source 1
Accurate comparison with the Central Valley, citing the paragraph
Comparison vague or not cited
Missing
Prediction
Reasonable prediction supported by two numbers and an idea from the source
Prediction with thin support
Missing
05
Quiz: 20 Questions
Interactive, with answers
Instructions
Questions 5-8, 14-17 use Source 1 in Guided Practice. Questions 3, 4, 10, 12, 13, 15 and 20 use Tables 1-3 in Direct Instruction, and questions 11, 16 and 19 use Diagrams 1-2. Choose the best answer, then check it.
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
Which of these is an example of land use?
Answer: A
Land use is what people do with land, and growing almonds is a use. The number of people (B) is population size and the share in cities (C) is about population distribution; rainfall (D) is part of the climate.
Question 2 of 20 · Multiple Choice
Which of these is a change in population distribution, not only in population size?
Answer: B
Moving from villages to cities changes where people live, even if the total stays the same, so it changes the distribution. Choices A, C and D change how many people there are (population size) but say nothing about where they live.
Question 3 of 20 · Multiple Choice
Use Table 1. In 1980, about what share of the world's people lived outside urban areas?
Answer: C
In 1980, 39.5% of the world's people lived in urban areas, so 100 - 39.5 = 60.5% lived outside them. Choice A is the urban share itself. Choice B (100 - 73.8) is the share of Americans outside urban areas in 1980, and choice D is the world's urban share in 1960.
Question 4 of 20 · Multiple Choice
Use Table 2. About how many times as many people lived in San Joaquin County in 2024 as in 1950?
Answer: D
816,108 ÷ 200,750 ≈ 4.07, about 4.1 times. Choice B divides by the 1970 count instead (816,108 ÷ 291,073 ≈ 2.8), and choice A divides by the 1990 count (≈ 1.7). Choice C is the difference in people (816,108 - 200,750 = 615,358), not "times as many."
Question 5 of 20 · Multiple Choice
According to Source 1, paragraph 1, about how many people live in the Central California Valley Ecoregion?
Answer: A
Source 1 says the ecoregion "is also home to nearly 5 million people." Choice B is San Joaquin County alone in 2024 (Table 2). Choice C misreads "nearly 70 percent," the share of land in cultivation, and choice D is the area of the ecoregion in square kilometers, which this excerpt leaves out.
Question 6 of 20 · Multiple Choice
According to Source 1, paragraph 4, what is "a major driver of change" in the Central Valley?
Answer: B
Paragraph 4 begins: "A major driver of change in the ecoregion is population growth." The full USGS chapter also mentions climate (A), but this excerpt leaves that part out and names population growth as the major driver; machines (C) and fires (D) are not mentioned.
Question 7 of 20 · Multiple Choice
According to Source 1, paragraph 4, what happens to farms when new development takes over farmland next to cities?
Answer: C
Source 1 says "farms are relocating to the ecoregion periphery and then converting traditional grazing lands (grassland/shrubland) into new agricultural uses." The periphery is the outer edge. None of the other choices is in the source; choice D reverses the change.
Question 8 of 20 · Multiple Choice
Source 1, paragraph 3, says: "In many instances, farmland converts to grassland/shrubland before being developed." What does this mean?
Answer: D
The sentence describes a step between farming and building: the fields stop being farmed and grass or shrubs grow until the land is developed. Choices A and C misread "converts" as planting, and choice B is not in the source.
Question 9 of 20 · Multiple Choice
Source 1, paragraph 2, says developed land increased "from 6.5 to 9.0 percent of the ecoregion area." By how many percentage points did it rise?
Answer: A
9.0 - 6.5 = 2.5 percentage points. Choice B adds the two percents. Choice C is the source's percent increase in developed land (37.7%), which compares the growth with the starting amount; it is not a difference in percentage points. Choice D is 9.0 ÷ 6.5 ≈ 1.4, a ratio.
Question 10 of 20 · Multiple Choice
Use Table 3. Which county gained people from domestic migration (moves within the United States) from 2020 to 2024?
Answer: B
Only San Joaquin has a plus sign for domestic migration (+5,618). Stanislaus (A), Santa Clara (C) and San Francisco (D) all lost more people to other parts of the country than they gained from them; their international migration numbers are positive, which is a different column.
Question 11 of 20 · Multiple Choice
On Diagram 1, which of these labeled counties grew by less than 20% from 1990 to 2024?
Answer: C
San Mateo is labeled +14%, in the lightest shade. Contra Costa (+46%) and Sacramento (+55%) are in the 40% to 60% shade, and Merced (+66%) is in the darkest shade.
Question 12 of 20 · Multiple Choice
Use Table 1. Which statement is supported by the data for 1960 and 2024?
Answer: D
The world rose 57.6 - 34.2 = 23.4 points, and the United States rose 80.1 - 70.0 = 10.1 points. Choice A reverses the shares (57.6% against 80.1%), choice B is false (79.1% to 80.1% is a rise), and choice C is false: 57.6 ÷ 34.2 ≈ 1.7, less than double.
Question 13 of 20 · Multiple Choice
Use Table 2. How many people did Stanislaus County add from 1990 to 2024?
Answer: A
556,972 - 370,522 = 186,450 people. Choice B subtracts the 1950 count instead (556,972 - 127,231), choice C adds the two numbers, and choice D turns the 50.3% growth rate into a number of people.
Question 14 of 20 · Multiple Choice
According to Source 1, paragraph 1, which natural characteristics make the Central Valley good farmland?
Answer: B
Source 1 names "flat terrain, fertile soils, a favorable climate." The other choices describe very different places and do not appear in the source.
Question 15 of 20 · Short Answer
Explain how population growth in the San Francisco Bay Area could change land use in San Joaquin County. Use Table 3 or Diagram 1, and Source 1, paragraph 4.
Model answer: Source 1 says population growth "in the San Francisco Bay area and Los Angeles, as well as in the Central Valley itself, has resulted in a high demand for land for urban uses." Table 3 shows that from 2020 to 2024 Bay Area counties such as Santa Clara lost many people to other parts of the country (-154,647), while San Joaquin gained a little from domestic migration (+5,618), and Diagram 1 shows San Joaquin grew about 70% from 1990 to 2024. As more people live in San Joaquin, farmland next to towns becomes homes, businesses and roads. The data do not show exactly where each new resident came from, so the link is likely but not proven. Rubric: 2 points for the chain with a data point and the quotation; 1 point for one of the two.
Question 16 of 20 · Short Answer
Source 1, paragraph 2, says that from 1973 to 2000 grassland/shrubland lost 1,782 km², developed land gained 1,129 km² and agriculture gained 358 km². How many square kilometers do the two gains add up to, and what fraction of the grassland loss is that? Use paragraph 4 to explain why agriculture could gain land even while farms were being built on.
Model answer: 1,129 + 358 = 1,487 km², which is 1,487 ÷ 1,782 ≈ 0.83, or about 83% of the grassland/shrubland loss. Paragraph 4 explains how agriculture could gain: when development takes over farmland near cities, "farms are relocating to the ecoregion periphery" and turning grazing land into new cropland. So farmland moved outward while grazing land shrank. Rubric: 2 points for 1,487 km² and about 83% with the relocation explanation; 1 point for the numbers or the explanation only.
Question 17 of 20 · Short Answer
Source 1, paragraph 5, says that as California's population grows, "additional demands will be placed on" the Central Valley. Name two land uses that could compete for the same land there, and explain why they compete.
Model answer: Homes and businesses (developed land) and farms compete for the same flat land near cities, because the flat terrain that makes good farmland also makes building easy, and new residents want to live close to existing towns. Farms and grazing also compete at the valley's edges, where relocated farms plow grazing land. Rubric: 2 points for two competing uses with a reason tied to the place; 1 point for two uses without a reason.
Question 18 of 20 · Short Answer
An invented town of 30,000 people grows by 40%. If each new home holds 3 people and about 8 new homes fit on one acre, about how many acres of new housing will the town need? Explain one way this could change land use around the town.
Model answer: 30,000 × 0.40 = 12,000 new people; 12,000 ÷ 3 = 4,000 homes; 4,000 ÷ 8 = 500 acres. If the town is surrounded by farms, about 500 acres of farmland or open land could become housing, and roads, schools and stores would need more land still. Rubric: 2 points for 500 acres with work and a land-use change; 1 point for one of the two.
Question 19 of 20 · Short Answer
Diagram 2 shows that the world passed the halfway mark for urban living around 2007. Explain why a global change like this matters for land use in a particular farming region such as the Central Valley.
Model answer: When a growing share of people live in and around cities, those urban areas spread outward, and the land at their edges, often farmland, is turned into homes, businesses and roads. The Central Valley lies next to the large Bay Area and contains growing cities of its own, so it feels this pull: Source 1 reports more developed land and farms moving to the valley's edges. A global pattern shows up as local change in places like this. Rubric: 2 points for linking the global change to a specific local land-use change with evidence; 1 point for a general link.
Question 20 of 20 · Short Answer
Table 3 shows that from 2020 to 2024 Stanislaus County lost 12,703 people to domestic migration but gained 8,347 from international migration. Yet Census estimates show its population still rose, from 553,285 (the April 2020 estimates base) to 556,972 (July 2024). Explain how a county can grow when more people move out to other U.S. places than move in.
Model answer: A county's population changes through births and deaths as well as migration. Stanislaus's net migration was -12,703 + 8,347 = -4,356 people, so the county grew only because more babies were born than people died, enough to make up the loss. Moves are only part of the story of population distribution, and the table does not say why people moved. Rubric: 2 points for the net migration figure and the role of births and deaths; 1 point for one of the two.
0 of 20 answered · 0 correct
06
Frequently Asked Questions
10 Questions
What does D2.Geo.12.6-8 mean?
D2.Geo.12.6-8 asks middle school students to explain how big changes in where people live change the way land is used in specific places. The full text is "Explain how global changes in population distribution patterns affect changes in land use in particular places." Students connect a large-scale pattern, such as urbanization, to what happens on the ground in one place.
What grade level is D2.Geo.12.6-8?
It is a C3 indicator for the grades 6-8 band, so it fits any middle school year. It is usually taught in a geography or world studies unit on population, cities or land use. The grades 9-12 indicator with the same number, D2.Geo.12.9-12, turns to the effects of catastrophes on trade, politics and migration.
What is the difference between population size and population distribution?
Size is how many people there are; distribution is where they live. A country's population can stay the same size while its distribution changes, for example when people move from farms to cities. This standard is about distribution, although growth in size often comes with it.
What is the difference between land use and land cover?
Land cover is what physically covers the ground, such as crops, grass, trees, water or buildings; land use is what people use the land for, such as farming, grazing or housing. Satellite studies like the USGS one on this page measure land cover, and geographers use it to see changes in land use.
Why does this lesson use California's Central Valley?
It is one of the country's most important farming regions and lies next to one of its largest urban areas, so the effect of growing population on farmland is easy to see. The U.S. Geological Survey has measured its land changes, and the Census Bureau publishes county populations going back decades, so students can work with real data from both sides of the chain.
Is the global part of the standard really covered with one valley?
Yes, if students connect the two scales. Table 1 and Diagram 2 show the global shift toward urban living, and the Central Valley is the particular place where that kind of shift shows up on the land. The homework and the exit ticket ask students to apply the same chain to other places.
What mistakes do students often make with this standard?
A frequent mistake is describing population growth and land change side by side without explaining how one causes the other. Students also confuse percent change with percentage points, and some state reasons for migration, such as housing prices, as facts when the data only count moves. Ask for every link of the chain, with evidence.
How can I assess D2.Geo.12.6-8?
Give students population data and a short land-change source for a place they have not studied, and ask them to explain the connection. Look for a change in where people live, a change in the place's population, a change in land use and a further effect, each supported by a number or a quotation. The homework on this page is built that way.
Are the numbers on this page real?
Yes, except the places labeled invented. County populations and migration figures come from the U.S. Census Bureau, the land-cover figures from the U.S. Geological Survey, and the urban shares from the World Bank, which bases them on United Nations estimates. Recent census numbers are estimates that are revised each year.
Does this lesson take a position on housing or farmland policy?
No. It explains how changes in where people live change land use and leaves policy choices aside. If students raise questions such as whether to protect farmland or build more housing, present them as issues on which residents and communities disagree, with good arguments on more than one side.
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Related Standards
5 standards
These standards connect to D2.Geo.12.6-8: prerequisites to review first, parallel standards at the same level, and next steps that build on it.
Before this lesson
D2.Geo.8.6-8Prerequisite
Analyze how human-environment relationships extend or contract settlement patterns
Standard text: National Council for the Social Studies (NCSS), The College, Career, and Civic Life (C3) Framework for Social Studies State Standards: Guidance for Enhancing the Rigor of K-12 Civics, Economics, Geography, and History (Silver Spring, MD: NCSS, 2013). NCSS was not involved in the production of this lesson and does not endorse it.
