BGCSE Geography (Botswana General Certificate of Secondary Education) flashcards

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

Bahama Banks

Two broad, shallow carbonate platforms (Great and Little Bahama Bank) where clear warm water allows coral and ooid formation; they are separated by deep channels such as the Tongue of the Ocean.

Ghyben-Herzberg lens

Fresh groundwater floating as a lens over denser seawater beneath limestone islands; the fresh-salt interface lies roughly 40 times deeper than the water table above sea level.

Blue hole

A deep, roughly circular flooded sinkhole in limestone, often containing stalactites and submerged caves; famous examples occur on Andros and in the Exumas.

Oolitic limestone

Sedimentary rock made of tiny concentric calcium carbonate spheres (ooids) cemented together; it forms the bedrock of most Bahamian islands and is highly permeable.

Mount Alvernia

The highest point in the Bahamas, about 63 metres above sea level, located on Cat Island; it illustrates the very low relief of the archipelago.

Over-the-Hill

Historic district of Nassau settled by freed Africans after emancipation in 1838; it is a key example of post-slavery settlement growth in the Bahamas.

Loyalist migration

Movement of American Loyalists and their enslaved people to the Bahamas after the 1780s, establishing cotton plantations and many Family Island settlements.

Family Islands out-migration

Movement of residents from the Out Islands to New Providence and Grand Bahama for jobs and services, especially after the decline of sponging and wrecking.

Nucleated coastal settlement

A settlement pattern in which homes cluster tightly near a harbour, bay or leeward shore for shelter, fishing access and trade links.

Stopover visitor

A tourist staying overnight in accommodation rather than arriving on a cruise ship; stopover visitors spend far more per head than cruise passengers.

Offshore financial services

Banking, trust and insurance business conducted for non-residents; it is a major Bahamian earner alongside tourism and a pillar of the economy.

Hurricane Dorian effect

The 2019 hurricane devastated Abaco and Grand Bahama, destroying homes and tourism infrastructure and showing the economy's exposure to a narrow, climate-sensitive base.

Crawfish export

Spiny lobster (locally called crawfish) is the Bahamas' leading fishery export, landed mainly in the Family Islands and sold largely to the United States.

Representative fraction

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

Six-figure grid reference

A location given by three easting digits followed by three northing digits, identifying a 100-metre square on a 1:50,000 topographic map.

Vertical exaggeration

The ratio of a cross-section's vertical scale to its horizontal scale; it shows how many times the relief has been stretched to make it visible.

Belt transect

A systematic sampling line along which quadrats or observations are recorded at intervals, used to investigate how a feature changes across a beach or mangrove.

Choropleth map

A map shading areas by value using graded colours or tones, effective for showing density or percentage data such as population per square kilometre.

Northeast trade winds

Steady winds blowing from the subtropical high toward the equator, deflected right in the Northern Hemisphere; they dominate Bahamian weather and cool the islands.

Hurricane formation conditions

Sea-surface temperature above about 27 degrees C, low wind shear, ample moisture and at least 5 degrees of latitude from the equator to supply Coriolis spin.

Mangrove adaptations

Prop roots for anchorage in mud, salt-excluding or salt-excreting tissues, and buoyant viviparous seedlings that establish in sheltered tropical shores.

Coral reef requirements

Warm water of about 20-29 degrees C, shallow depth for sunlight, clear low-sediment water and normal salinity; silt or fresh water kills the coral polyps.

Longshore drift

The zigzag movement of sediment along a beach as swash carries it up at an angle and backwash returns it straight down, producing net transport in the wave direction.

Wave refraction

Bending of wave crests as they approach an irregular shore, concentrating energy on headlands and spreading it in bays, which erodes headlands and deposits in bays.

Fringing reef

A coral reef growing directly from a shoreline, with no lagoon or only a shallow one; it is the commonest reef type around Bahamian islands.

Karst landscape

Terrain formed on soluble rock such as limestone, with sinkholes, caves, dry valleys and disappearing streams produced mainly by chemical solution.

Rock cycle

The continuous set of processes linking igneous, sedimentary and metamorphic rocks through melting, cooling, weathering, deposition, burial and metamorphism.

Carbonation weathering

Chemical weathering in which carbon dioxide dissolved in rainwater forms weak carbonic acid that dissolves calcium carbonate in limestone, creating karst features.

Demographic transition

A model of population change through four stages, from high birth and death rates to low birth and death rates as health, education and incomes improve.

Dependency ratio

The number of people under 15 plus those over 64, divided by the working-age population and multiplied by 100; it shows the burden on workers.

Intensive farming

A system using high inputs of labour, capital or fertiliser per hectare to obtain high yields, typical of market gardening and cash cropping near urban markets.

Human Development Index

A composite development measure combining life expectancy, mean and expected years of schooling, and gross national income per capita, ranging from 0 to 1.