Geography: The Living World

Ecosystems
1. Ecosystem: unit that includes all the living parts (plants and animals) and the non living (physical) parts (soil and climate) in an area.
2. Organisms in ecosystems can be classed as producers, consumers or decomposers
3. Producer: an organism that uses sunlight energy to produce food
4. Consumer: an organism that uses that gets its energy by eating other organism – it eats producers or other consumers!
5. FOOD CHAIN: shows what eats what!
6. FOOD WEB: shows lots of food chains and how they overlap
7. Decomposer: an organism that gets its energy by breaking down dead material. Bacteria and Fungi for example!
8. When dead material is decomposed, nutrients are released into the soil. The nutrients are then taken up from the soil by plants. The plants may be eaten by consumers. When the plants or consumers die, the nutrients are returned to the soil. The transfer of nutrients is called the nutrients cycle
9. A change in one part of the ecosystem has an impact on other parts - eg. hot, dry summers or having a hedgerow trimmed
Global Distributions
1. Tropical Rainforests
  1. Found near EQUATOR
  2. AREAS
    1. Central America, Amazon, central Africa and south east Asia
  3. Climate
    1. hot, wet climate with no definite seasons
  4. Soil
    1. isn't very fertile as heavy rainfall washes nutrients away, nutrients at the surface due to decayed leaf fall, but this layer is very thin as decay is fast in the warm, moist conditions
  5. Vegetation Structure
    1. Three tree layers and a shrub layer
      1. canopy 30m trees
      2. emergents 40m branches most light
      3. undercanopy 15 m
      4. Shrub 10m - little light
  6. Plant Adaptation
    1. thick waxy leaves that have pointed tips - run off - adapt to heavy rainfall
    2. tall trees have buttress roots to support trunks in very shallow soil
    3. Trees = deciduous - drop leaves in drier periods to reduce water loss
2. Hot Deserts
  1. Found - 15 and 30 degrees north and south of the equator - less rainfall
    1. AREAS
      1. North Africa, the Middle East, South West USA, large parts of Australia
    2. Climate
      1. Little rainfall - rain once every 2 or 3 years. hot days (45 degrees) cold nights 5 degrees
    3. Soil
      1. shallow with a coarse, gravelly texture. hardly any leaf fall so soil isn't very fertile
    4. Vegetation Structure
      1. Plant growth is sparse due to lack of rainfall. Plants that do grow include cacti and thorn bushes
    5. Plant Adaptation
      1. roots are extremely long to reach deep water
      2. Cacti have swollen stems to store water and have thick waxy skin to reduce water loss
      3. Cacti have small, spiky leaves to reduce water loss
3. Temperate Deciduous Forests
  1. Found between 40 and 60 degrees north and south of the equator - 4 distinct seasons
    1. AREAS
      1. Most of Europe, South east USA, China and Japan
    2. Climate
      1. 4 distinct seasons - rainfall all year round
    3. Soil
      1. The solid is deep and very fertile because theres think layer of leaf fall
    4. Vegetation Structure
      1. three main plant layers
        30 m - top layer (oak)
        Shrub layer - 20m (hawthorn)
        undergrowth 5m - (brambles)
    5. Plant Adaptation
      1. trees are deciduous - reduces water loss from leaves in months where water is harder to get
Tropical Rainforest Deforestation
1. Farming
2. Mineral Extraction
3. Commercial Logging
4. Population pressure
5. Road Building
Deforestation
1. Environmental Impacts
  1. fewer trees = fewer habitats
  2. no trees to hold solid together - heavy rain washes away the soil (soil erosion)
  3. soil from deforestation is washed into rivers
  4. without trees = no leaf fall+ no nutrients supply to the soil = less fertile
  5. Trees remove CO2 = more C02 in the atmosphere = adds to Global Warming
2. Social Impacts
  1. quality of life for locals improves as more jobs
  2. Native tribes forced out causing conflict
3. Economic Impacts
  1. Logging, farming and mining create jobs
  2. Money made from selling timber, mining and commercial farming
4. Political Impacts
  1. Theres pressure from foreign governments to stop deforestation
Tropical Rainforest: Sustainable Management
1. Selective Logging
2. Replanting
3. Reducing demand for Hardwood
4. Educating
5. Ecotourism
6. Protection - environmental laws

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Geography: The Living World

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