Posts Tagged ‘distribution’

  • Define the term biome.
Biome:
A collection of ecosystems sharing similar climatic conditions, like tundra, tropical rainforest and desert. A biome has distinctive abiotic factors and species which distinguish it from other biomes. Water, insolation and temperature are the climate controls important when understanding how biomes are structured, how they function and where they are found round the world. Biomes usually cross national boundaries and do not stop at a border.
  • Explain the distribution, structure and relative productivity of tropical rainforests, deserts, tundra and any other biome.
It is possible to group the biomes into 6 categories with sub-categories in each one:
  • freshwater
  • marine
  • desert
  • forest
  • grassland
  • tundra
In IB however it is required that you need to be able to explain the distribution, structure and relative productivity of tropical rainforests, deserts, tundra and one other biome.Climate should only be explained in terms of temperature, precipitation and insolation only.
In this picture you can see where each biome is located.
Tropical rainforest:
  • high temperatures (average 26 C )
  • high rainfall (over 2500 mm yr -1)
  • near the equator
  • high light levels throughout the year
  • all-year round growing season
  • high levels of photosynthesis
  • high rates of NPP throughout the year
  • high diversity of animals and plants
  • low levels of nutrients in the soil
Deserts:
  • cover 20-30 percent of the land surface
  • dry air
  • high temperatures (45-49 C in day)
  • low¬†precipitation (250 mm yr-1)
  • low rates of photosynthesis
  • low NPP rates
  • vegetation scarce
  • soil rich in nutrients and can support plant that can survive there
Tundra:
  • found in high latitudes
  • days are short
  • limit levels of sunlight
  • water may be locked up in ice, limiting water resources
  • photosynthesis and productivity rates are low
  • low temperatures
  • soil may be permanently frozen
  • nutrients in soil are limited
Temperate forest:
  • seasonal weather (hot summers/cold winters)
  • 2 types of tree types in forests; Evergreen + deciduous could be in one forest or contain both trees
  • rainfall average between 500-1500 mm yr-1
  • productivity lower than rainforest
  • mild climate, lower average temperature / lower rainfall

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