AP Human Geography: Comprehensive Guide to Models and Theories

Demographic Transition Model (DTM)\n* The Demographic Transition Model (DTM) outlines the transition of a country from an agricultural subsistence economy to an industrialized nation through four distinct stages.\n* In this process, demographic patterns shift from extremely high birth and death rates to low birth and death rates.\n* Population growth rates exhibit a specific pattern: they skyrocket during the middle stages and then fall again as the transition nears completion.\n* The Crude Death Rate (CDR) is the first to fall, primarily due to the influx of better health technology.\n* Following the drop in death rates, the birth rate gradually falls to align with the new social structure of the industrialized society.\n\n# Epidemiologic Transition Model\n* This model identifies shifts in disease vulnerability that occur in patterns similar to those seen in the Demographic Transition Model (DTM).\n* Early Stages: These are characterized by the spread of plague and pestilence, resulting from poor medical technology.\n* Industrialization Stages: As industrialization proceeds, diseases related to urban life begin to spread.\n* Later Stages: Diseases that were once thought to be eradicated can reappear as more-developed societies come into easier contact with less-developed regions still struggling with primitive diseases, such as smallpox and the bubonic plague.\n* Leading Causes of Death: In the later stages of the model, the primary causes of death are associated with aging, most notably heart disease.\n\n# Gravity Model of Spatial Interaction\n* When applied specifically to the context of migration, this model posits that larger places have a stronger pull and attract more migrants than smaller places.\n* The model also incorporates distance: destinations that are more distant exert a weaker pull effect compared to closer opportunities of the same caliber.\n\n# Zelinsky Model of Migration Transition\n* This model states that migration trends follow the stages of demographic transition.\n* A key principle is that people become increasingly mobile as industrialization develops within a country.\n* Stage $2$: Countries in this stage see significant international migration as people search for more space and opportunities in more advanced countries.\n* Stage $3$ and $4$: These are the typical destinations for migrants leaving Stage $2$ countries.\n* Stage $4$: Countries in this stage exhibit less emigration and a higher prevalence of intraregional migration.\n\n# Ravenstein’s Laws of Migration\n* Developed by E.G. Ravenstein in the $19$th century using data from England, these ‐laws‐ outline a series of patterns explaining migration.\n* Migration is driven by push and pull factors:\n * Push Factors: Unfavorable conditions that drive people out of a location, such as oppression and high taxes.\n * Pull Factors: Attractive opportunities that cause people to migrate into a region.\n* Key Laws of Migration:\n * Better economic opportunities are the chief cause of migration.\n * Migration typically occurs in multiple stages rather than a single move.\n * The majority of people move only short distances.\n * Migrants who travel longer distances generally choose big-city destinations.\n * Urban residents are less migratory than rural residents.\n * For every migration stream, there is a corresponding counterstream.\n * Specific factors such as gender, age, and socio-economic level influence the likelihood of a person to migrate.\n* Contextual Note: These laws were applied specifically to the timeframe and context of Ravenstein’s original analysis.\n\n# Von Thunen’s Model of Agricultural Land Use\n* Developed by German geographer Johann Heinrich von Thunen, this model explains and predicts agricultural land use patterns within a theoretical state.\n* The primary variable in the model is varying transportation cost.\n* Predicted Patterns: The model predicts that more-intensive rural land uses will be located closer to the marketplace, while more-extensive rural land uses will be located farther from the city’s marketplace.\n* Structure: These rural land use zones are organized into a series of concentric rings surrounding the market.\n\n# Least Cost Theory\n* Developed by Alfred Weber, this theory of industrial location predicts where industries will situate themselves based on a cost analysis of three factors: transportation, labor, and agglomeration.\n* Assumption of Goal: Weber assumes that an industry will choose a location based on the desire to minimize production costs to maximize profits.\n* Drawbacks: The model assumes an immobile and equal labor force, which is often not the case in reality.\n\n# Locational Interdependence\n* Hotelling’s theory asserts that the locational choices of an industry are heavily influenced by the positions of its chief competitors and related industries.\n* Industrial locations are not decided in isolation; firms must consider where other related industries already exist.\n\n# Rostow’s Modernization Model\n* Developed in the $1950s$, this model represents the liberal development ideology (contrasted with structuralist theory).\n* The model suggests all countries develop through a five-stage process:\n * Initiation: The cycle begins with investment in a ‐takeoff‐ industry.\n * Comparative Advantage: This investment allows the country to grow a comparative advantage.\n * Diffusion: The resulting economic gain eventually diffuses throughout the entire national economy.\n* Drawbacks: The model fails to identify cultural and historic differences in development trajectories because it is based specifically on North American and western European histories.\n\n# Borchert’s Model of Urban Evolution\n* Created in the $1960s$, this model explains the growth of cities across four phases of transportation history:\n * Stage $1$: The ‐sail wagon‐ era, spanning from $1790$ to the $1830s$.\n * Stage $2$: The ‐iron horse‐ era, spanning from $1830$ to $1870$.\n * Stage $3$: The ‐steel rail‐ epoch, spanning from $1870$ to $1920$.\n * Stage $4$: The current era of car and air travel, which began after $1920$.\n\n# Central Place Theory\n* Developed in the $1930s$ by Walter Christaller, this model predicts patterns of urban places across a map.\n* Christaller analyzed hexagonal, hierarchical patterns of settlements including cities, villages, towns, and hamlets.\n* These are arranged according to varying degrees of ‐centrality,‐ which is determined by the central place functions existing in urban places and the hinterlands they serve.\n\n# Concentric Zone Model\n* Devised in the $1920s$ by Ernest Burgess, this model explains growth patterns in North American urban spaces.\n* Main Principle: Cities are viewed as a series of concentric rings that grow and expand outward; as they grow, new rings are added and old ones change character.\n* Key Elements: Important features include the Central Business District (CBD) and the peak land value intersection.\n* Zones Identified (from center outward):\n * Central Business District (CBD): The innermost ring.\n * Transitional Zone: Contains recent immigrants, deteriorating housing, factories, and abandonment.\n * Working Class Zone: Characterized by single-family tenements.\n * Residential Zone: Contains single-family homes with yards and garages.\n * Commuter Zone: The outermost ring, consisting of suburbs.\n\n# Bid-Rent Curve\n* These curves show variations in the rent different users are willing to pay for land at different distances from the peak point of accessibility and visibility (the market/CBD).\n* Distance and Cost: Because transportation costs increase as one moves away from the market, rents usually decrease as distance from the market increases.\n* Land Use Variation: Different types of land use (commercial retail, industrial, agriculture, housing) generate distinct bid-rent curves.\n* Application: Bid-rent curves explain the concentric rings of land use identified in the Concentric Zone Model.\n\n# Sector Model\n* Conceived by Homer Hoyt in the $1930s$, this model predicts North American urban growth patterns.\n* It posits that similar land uses and socioeconomic groups cluster in linear sectors (wedges) that radiate outward from a Central Business District (CBD), typically along transportation corridors.\n\n# Multiple-Nuclei Model\n* Developed in the $1950s$ by Chauncy Harris and Edward Ullman.\n* The model assumes that growth occurs independently around several major foci or ‐focal nodes.‐\n* Many of these nodes are located far from the original CBD and are only marginally connected to it.\n\n# Urban Realms Model\n* Developed by James Vance in the $1970s$ to explain changing urban patterns as the automobile became prevalent.\n* The model describes the emergence of large suburban ‐realms‐ that are functionally tied to a mixed-use suburban downtown, or ‐mini-CBD.‐\n* These realms maintain relative independence from the original central city CBD.\n\n# Latin American City Model\n* Created by Larry Ford and Ernest Griffin to describe the pattern of urban growth in Latin America.\n* Cultural and Historic Imprints: The model includes elements of Latin American culture, colonization, and globalization, such as a prominent plaza and heavy growth surrounding the CBD.\n* Residential Patterns: In this model, residential quality decreases as distance from the CBD increases.\n* Defined Zones:\n * Zone of Maturity: Populated with services and a wealthier population.\n * Zone of In Situ Accretion: A transitional zone showing signs of moving toward the zone of maturity.\n * Zone of Squatter Settlements: Where recent urban migrants establish makeshift housing.", "title": "AP Human Geography: Comprehensive Guide to Models and Theories"}