S-Cool Revision Summary

S-Cool Revision Summary

The Overview of Ecosystems

  • Ecosystems are entire living communities of plants and animals that, although diverse in nature, share common characteristics.
  • Ecosytems can be split into two main sections, abiotic and biotic elements.
  • Climate, soils and vegetation interact closely to produce the characteristic nature of an individual ecosystem.

Coniferous Woodlands

  • The temperature in the summer varies between 12 and 18oC, with temperatures falling below freezing for the winter months.
  • The total precipitation amount will be approximately 500mm.
  • The main soil found in coniferous forests is called a podsol.
  • Coniferous trees are evergreen, meaning that they have leaves all year round, and therefore can always photosynthesise.
  • The trees are extensively used as timber and for paper making

Deciduous Woodlands

  • The summer temperatures range between 15 and 20°C, whilst the cool winters don't generally drop below zero.
  • Rainfall is moderate, usually between 1000 and 1500mm.
  • The typical soil of a British deciduous woodland is a brown earth.
  • Deciduous trees are ones which drop their leaves in the autumn.
  • One of the primary reasons for the clearance of many of the deciduous woodlands around Britain was to use the area for agriculture.

Deserts

  • Temperature often remains above 30°C for long periods.
  • They tend to receive an average of less than 300mm of rain each year.
  • Desert soils are alkaline, and are very dry with little humus.
  • Plants have to cope with very little water in the hot desert. Species such as cacti have evolved to reduce water loss to a minimum.
  • Many plants have seeds that only germinate when the rains come.

Mediterranean Woodlands and Scrub

  • The Mediterranean experiences hot, dry summers, with temperatures usually between 20 and 25°C.
  • There is moderate rainfall, of around 800mm, which falls mainly in the winter.
  • Mediterranean soils are a mixture between brown earths in the wetter areas and desert soils in the dry places.
  • The Mediterranean hillsides were once covered in dense deciduous and coniferous forests.
  • Where the forests have been removed a dense shrubland has replaced them.
  • Forest fires are very common in the Mediterranean area, and this has helped to destroy much of the original woodland.

Tropical Rainforests

  • Hot throughout the year, with temperatures ranging between 25 and 30°C.
  • There also is a massive level of precipitation, usually between 2000 and 3000mm each year.
  • Rainforest soils are called latsols.
  • Tropical rainforests boasts a huge variety of vegetation and animal life.
  • They can be divided into five simple layers, from the canopy to the forest floor.
  • Humans use the rainforests for logging, ranching, dam projects, subsistence farming, and mining.

Management of Ecosystems

  • The main method of management is called sustainability. This means that the forests are used, but in a way which does not affect their long term growth.
  • By removing the trees, humans have also removed the main source of nutrients in the soil in the rainforests.
  • By chopping down vast areas of both the rainforests and deciduous woodlands, less carbon dioxide can be processed, meaning that there is more in the atmosphere.