DSST Introduction to Geography flashcards

33 cards. Read the term and the definition here. The deck at the top of this page is optional.

Representative fraction

A map scale written as a ratio, such as 1:50,000, meaning one unit on the map equals 50,000 of the same units on the ground.

Mercator projection

A cylindrical, conformal map projection that preserves local angles and shapes and shows straight rhumb lines, but increasingly exaggerates area toward high latitudes.

Contour line

A line on a topographic map connecting points of equal elevation. Closely spaced contours mean steep terrain; contours crossing a stream form a V pointing upstream.

Large-scale map

A map with a small representative fraction denominator, such as 1:10,000, covering a small area with considerable detail, typical of city and property maps.

Remote sensing

Acquisition of information about Earth's surface from instruments not in physical contact with it, such as satellites and aircraft, used for land cover and weather mapping.

Oblate spheroid

Earth's shape, slightly flattened at the poles and bulging at the equator, so equatorial diameter exceeds polar diameter by roughly 42 kilometers.

Plate tectonics

The theory that Earth's lithosphere consists of rigid plates moving over the asthenosphere, producing earthquakes, volcanoes, and mountain belts mainly along plate boundaries.

Subduction zone

A convergent boundary where one lithospheric plate descends beneath another, generating deep ocean trenches, volcanic arcs, and frequent powerful earthquakes.

Troposphere

The lowest atmospheric layer, containing most atmospheric mass and water vapor, where temperature generally decreases with altitude and most weather occurs.

Soil horizons

Layers within a soil profile, typically O organic litter, A humus-rich topsoil, B subsoil of accumulated leached material, C weathered parent material, and R bedrock.

Drainage divide

A ridge or elevated boundary separating adjacent watersheds, determining which stream system receives precipitation falling on either side.

Greenhouse effect

Atmospheric gases absorb and re-emit outgoing longwave radiation, warming the surface; enhanced by human emissions of carbon dioxide and methane.

Possibilism

The view that the physical environment offers a range of possibilities and that human technology and culture determine which options a society uses.

Environmental determinism

The largely discredited view that physical environment directly shapes and limits human culture, economic development, and behavior.

Cultural landscape

The visible imprint of human activity on the physical environment, including fields, roads, settlements, terraces, and irrigation systems.

Desertification

Land degradation in arid and semi-arid regions, often from overgrazing, deforestation, and drought, reducing vegetation and productive capacity.

Sustainable development

Development that meets present needs without compromising the ability of future generations to meet theirs, balancing economic, social, and environmental goals.

IPAT equation

A formula expressing environmental impact as the product of population size, affluence (consumption per person), and technology (impact per unit of consumption).

Cultural diffusion

The spread of cultural traits, ideas, or practices from one society or place to another, through migration or through expansion from a source area.

Formal region

A region defined by uniformity in one or more measurable characteristics, such as a language area, climate zone, or political unit.

Functional region

A region organized around a central node, such as a metropolitan area or market hinterland, defined by interaction and flows rather than uniformity.

Lingua franca

A bridge language used for communication between speakers of different native languages, often for trade, administration, or education.

Universalizing religion

A religion that actively seeks converts everywhere and is not tied to a single ethnic group or place, such as Christianity, Islam, or Buddhism.

Demographic transition

A model of population change moving from high birth and death rates through rapid growth to low birth and death rates as societies industrialize.

Physiological density

Population divided by the area of arable land, indicating how many people each unit of farmland must support.

Push and pull factors

Conditions that drive people away from a place, such as poverty or conflict, and conditions that attract them to another, such as jobs or safety.

Nation-state

A political unit whose territorial boundaries largely coincide with the homeland of a single national group sharing culture and identity.

Ring of Fire

A belt around the Pacific Ocean where many earthquakes and volcanic eruptions occur because of subduction along convergent plate margins.

Sahel

A semi-arid transition zone south of the Sahara stretching across Africa, vulnerable to drought and desertification.

Monsoon

A seasonal reversal of wind direction that brings heavy summer rainfall to South and Southeast Asia and dry conditions in winter.

Altitudinal zonation

The arrangement of climate and vegetation belts by elevation in mountains, as in Latin America's tierra caliente through tierra helada zones.

Permafrost

Permanently frozen subsoil found in high-latitude and high-altitude regions such as Siberia and northern Canada, thawing under warming climates.

Great Rift Valley

A long depression formed by crustal divergence, running through East Africa and Southwest Asia, marked by faulting and volcanism.