AP Human Geography Crash Course
Chapter 2
Key Geographic Models and Theories
1. Demographic Tr ansition Model (DTM)
In the four stages of t ransit ion from an agricultural subsistence economy to an industrialized count ry, demographic patterns move from extremely high birth and death
rates to low birth and deat h rates. In t he process, population growth rat es skyrocket
and then fall again. The crude death rate first falls because of t he influx of better
healt h technology, and then the birth rat e gradually falls to match t he new social
structure.
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Dem ographic Transit ion Model
2. Epidemiologic Transit ion Model
Disease vulnerability shifts in patterns similar to t he DTM. In t he early stages, plague
and pestilence spread as a result of poor medical technology. As industrialization proceeds, d iseases related t o urban life spread. In lat er stages, diseases once thought eradicat ed reappear as more-developed societies come into easier contact w ith less-developed r egions struggling with the more primitive diseases, such as smallpox and t he
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AP Human Geography Crash Course
bubonic plague. Leading causes of death in lat er st ages are relat ed to diseases associat ed with aging, such as heart disease.
3. Gravity Model of Spatial Int eraction
When applied to migration, larger places attract more migrants than do smaller
places. Additionally, destinations t hat are more distant have a weaker pull effect than
do closer opportunities of t he same caliber.
4. Zelinsky Model of Migration Transition
Migration trends follow demographic transition stages. People become increasingly
mobile as industrialization develops. More int ernational migration is seen in stage 2 as
migrant s search for more space and opportunities in count ries in stages 3 and 4. Stage
4 countries show less emigration and more intra regional migration.
5. Ravenstein's Laws of Migration
In the 19th century, E.G. Ravenstein used data from England to outline a series of
"laws" explaining patterns of migration. His laws st ate t hat migration is impact ed by
push and pull factors. Unfavorable condit ions, such as oppression and high taxes, push
people out of a place, whereas attractive opportunities, called pull factors, cause them
to migrate into regions. Ravenstein's laws stat e that better economic opportunit ies
are the chief cause for migration; t hat migration occu rs in multiple stages, rather t han
one move; t hat t he majority of people move short d ist ances and that those who migrate longer distances choose big-city desti nations; t hat urban resident s are less migratory than rural residents; that for every migration st ream, there is a count erstream;
and fact ors such as gender, age, and socioeconomic level influence a person's li keli hood to migrate. Keep in mind t hat his "laws" applied to the timeframe and context of
his analysis.
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AP Human Geography Crash Course
•
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Von Thiinen's Model of Agriculturol Land Use
6. Von Thunen Model
Developed by German geographer Johann Heinrich von Thunen, this model explains
and predict s agricult ural land use pat terns in a theoretical st ate by varying transportation cost. Given t he model's assumptions, the pattern t hat emerges pred icts more-intensive ru ral land uses closer to the marketplace, and more-ext ensive rural land uses
farther from t he city's marketplace. These rural land use zones are d ivided in t he model into concentric rings.
7. Least CostTheory
This is Alfred Weber's theory of indust rial location, explaining and predicting where industries will locate based on cost analysis of transport ation, labor, and agglomeration
factors. Weber assumes an indust ry will choose its location based on t he desire to minimize production cost s and t hus maximize profits. Drawbacks to the model include its
assumption of an immobile and equal labor force.
8. Locational lnterdependence
Hotelling' s theory of locational interdependence asserts t hat an industry' s locational
choices are heavily influenced by the location of t heir chief competitors and relat ed industries. In ot her words, indust ries do not make isolated decisions on locations without considering where other, related indust ries exist.
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AP Human Geography Crash Course
HIGH MASS
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9. Rostow's Modernization Model
Developed in the 1950s, this model exemplifies the liberal development ideology, as
opposed to structuralist theory.
Under this model, all countries develop in a five-stage process. The development cycle
is init iated by investment in a takeoff industry t hat allows the country to grow a comparative advantage, which sparks greater economic gain t hat event ually diffuses
throughout t he country's economy. Drawbacks to this model include its not identifying cultural and historic d ifferences in development trajectories because it is based on
Nort h American and western European development histories.
10. Borchert 's Model of Urban Evolution
Borchert creat ed this model in t he 1960s to predict and explain the growth of cities in
four phases of t ransportation history: stage 1, t he "sail wagon" era of 1790- 1830; stage
2, t he "iron horse" era of 1830- 1870; stage 3, the "st eel rail" epoch of 1870- 1920; and
stage 4, t he current era of car and air travel that began after 1920.
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AP Human Geography Crash Course
•
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High-Order Central Ploce
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Hexagonal Market Areas Predicted by Christoller's Centro/ Place Theory
11. Central Place Theory
Developed in t he 1930s by Walter Christaller, t his model explains and pred icts patterns
of urban places across the map. In his model, Christaller analyzed t he hexagonal, hier·
archical pattern of cities, villages, towns, and hamlets arranged according to their
varying degrees of centrality, det ermined by the cent ral place functions existing in ur·
ban places and the hinterlands t hey serve.
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Concentric Zone Urban Land Use Model
12. Concentric Zone Model
This model was devised in the 1920s by Ernest Burgess to predict and explain the
growt h patterns of Nort h American urban spaces. Its main principle is t hat cities can
be viewed from above as a series of concentric rings; as the city grows and expands,
new rings are added and old ones change character. Key elements of the model are t he
central business d ist rict and t he peak land value intersection.
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Bid -Rent Curve
13. Bid-Rent Curve
Bid-rent curves show the variations in rent different users are willing to pay for land at
different distances from some peak point of accessibility and visibility in the market,
oft en the CBD. Because transport ation costs increase as you move away from the market (often t he CBD), rent s usually decrease as distance increases from t he market. Importantly, d ifferent types of land use (commercial retail, indust rial, agriculture, housing) generate d ifferent bid-rent curves. Bid-rent cu rves explain the series of concentric
rings of land use found in the concent ric zone model.
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Sector Model of Urban Land Use
14. Sector Model
This model, conceived by Homer Hoyt, predicts and explains North American urban
growt h patterns in the 1930s in a pattern in which similar land uses and socioeconomic
groups clustered in linea r sectors rad iat ing out ward from a central business district,
usually along transportation corridors.
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AP Human Geography Crash Course
Legend
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Multiple-Nuclei Model of Urban Land Use
15. Multiple-Nuclei Model
Developed in the 1950s by Chauncy Harris and Edward Ullman, this model explains the
changing growt h pattern of urban spaces based on t he assumption that growth occurred independently around several major foci (or nodes), many of which are far away
from the central business district and only marginally connected to it.
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Urban Realms Model
16. Urban Realms Model
)ames Vance developed this model in the 1970s to explain and pred ict changing urban
growth patterns as the automobile became increasingly prevalent and large subu rban
"realms" emerged. The subu rban regions were functionally tied to a mixed-use suburban downtown, o r mini-CBD, with relative independence from t he original CBD.
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AP Human Geography Crash Course
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Lat in A merican City Model (Griffin-Ford Model)
17. Lati n American City Model
Larry Ford and Ernest Griffin creat ed a model of the pattern of urban growth in Lati n
America. Their model contains element s of Latin American culture and imprints of colonization and globali zation, such as a prominent plaza and heavy growth around t he
CBD. However, in t he Latin American pattern shown in their model, residential quality
decreases with distance from the CBD. The model also present s a zone of maturity,
populat ed with services and a wealthier population; a zone of squat ter settlements,
where recent urban migrant s set up makesh ift housing; and a zone of in situ accretion,
which is a transitional zone that shows signs of transition to a zone of maturity.
' ~
Test'~
Tip
r.:;:y
Check out REA's AP Human Geography test prep book for practice drills to
quiz your memory of key terms and models in AP Human Geography. There
are also many practice FRQs and multiple-choice questions, categorized by
test theme and similar to questions you will face on the actual AP Human
Geography exam. When using the practice-exam questions, be sure to read
the explanations for each question. The explanations will help train your
thinking and improve your performance on the exam.
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