Geography - End of Year Huit

Rivers: Processes, Landforms, and Flooding

Processes:

  1. Erosion: The wearing away of the river's banks and bed.

    • Types:

      • Hydraulic action: Water forces air into cracks, causing them to expand.

      • Abrasion: Rocks carried by the river scrape against the bed and banks.

      • Attrition: Rocks collide and break into smaller pieces.

      • Solution: Minerals dissolve in the water.

  2. Transportation: The movement of sediments.

    • Types:

      • Traction: Large rocks rolled along the riverbed.

      • Saltation: Small pebbles bounced along the bed.

      • Suspension: Fine particles carried within the water.

      • Solution: Dissolved materials transported in the water.

  3. Deposition: The laying down of material transported by the river.

Landforms:

  1. Upper Course:

    • V-shaped valleys

    • Interlocking spurs

    • Waterfalls and gorges

  2. Middle Course:

    • Meanders

    • Ox-bow lakes

  3. Lower Course:

    • Floodplains

    • Levees

    • Deltas

Flooding:

  1. Causes:

    • Heavy rainfall

    • Snowmelt

    • Deforestation

    • Urbanization

  2. Impacts:

    • Property damage

    • Loss of life

    • Disruption to transport

    • Waterborne diseases

  3. Management:

    • Dams and reservoirs

    • Levees and embankments

    • River channelization

    • Floodplain zoning

Population: Push/Pull Factors, Problems of Overpopulation, Population Pyramids

Push/Pull Factors:

  • Push Factors: Reasons people leave an area.

    • Lack of jobs

    • Poor living conditions

    • Political instability

    • Natural disasters

  • Pull Factors: Reasons people move to an area.

    • Better job opportunities

    • Higher living standards

    • Political stability

    • Better services (education, healthcare)

Problems of Overpopulation:

  • Shortage of resources (water, food)

  • Increased pollution

  • Unemployment

  • Strain on infrastructure (schools, hospitals)

  • Housing shortages

Population Pyramids:

  • Shape Interpretation:

    • Wide base: High birth rate

    • Narrow top: High death rate or lower life expectancy

    • Bulge in middle: High proportion of working-age population

  • Stages:

    • Expanding: High birth and death rates, wide base

    • Stationary: Low birth and death rates, more uniform shape

    • Contracting: Lower birth rates than death rates, narrow base

Tropical Rainforests: Location, Climate, Plant and Animal Adaptations, Layers, Deforestation, Sustainable Management

Location:

  • Found near the Equator.

  • Examples: Amazon (South America), Congo (Africa), Southeast Asia.

Climate:

  • Hot and humid all year round.

  • High rainfall (over 2000 mm per year).

Plant and Animal Adaptations:

  • Plants:

    • Drip tips: Leaves with pointed tips to shed water.

    • Buttress roots: Support tall trees in shallow soil.

  • Animals:

    • Camouflage: To hide from predators.

    • Strong limbs: For climbing and swinging (e.g., monkeys).

Layers of the Forest:

  1. Emergent Layer: Tallest trees, plenty of sunlight.

  2. Canopy Layer: Dense layer forming the roof.

  3. Understory Layer: Limited sunlight, small plants.

  4. Forest Floor: Dark, damp, decomposition occurs here.

Deforestation:

  • Causes:

    • Logging

    • Agriculture (cattle ranching, palm oil)

      Urban expansion

  • Impacts:

    • Loss of biodiversity

    • Climate change

    • Displacement of indigenous communities

Sustainable Management:

  • Selective logging

  • Reforestation

  • Conservation areas

  • Ecotourism