Ecosystems

• Nutrient Cycle Diagram

  Nutrients are constantly recycled in ever ecosystem.

  A) deforestation

  B) uptake by plants

  C) input dissolved in rain

  D) loss by leaching

  E) input weathered from rock

  F) litter decomposes

  G) fallout as tissues die

  
• Food chains + Food Webs

  Show what organisms eat.

  If one part of an ecosystem, it affects all the other parts that depend on it.
• Abiotic factors in an ecosystem:

  • Sunshine + rain are needed for photosynthesis, so are essential to the ecosystem. Other climactic elements (e.g. wind and frost) are also important.
  • Rocks help in the formation of soils, and rock type is important. Weathering releases nutrients stored in rocks into the ecosystem.
  • Soils store water and contain nutrients which plants can use. Soils are home to insects and decomposers.
• Biotic factors in an ecosystem:

  • Animals
  • Plants provide food and shelter for many animals
  • Micro-organisms, such as fungi and bacteria, are decomposers. They help break down dead plants and animals, releasing nutrients into the ecosystem so they can be recycled.
  • Insects and decomposers live in soils
• Ecosystem

  A community of living things interacting with each other and their environment.
• Producers

  Organisms that produce their own food. Get energy from sunlight.
• Nutrient Cycling

  The way in which nutrients are moved around an ecosystem.
• Distribution of Global Ecosystems

  In each climate graph, red line shows monthly temp averages, blue bars show precipitation.

  A) tropical forest

  B) mediterranean

  C) deserts

  D) deciduous forests

  E) coniferous forest

  F) tundra

  G) temperate grassland

  H) savana grassland

  
• Tropical Rainforests

  Found along the equator in Asia, Africa and South America.

  
  

  Hot and wet all year round.

  
  

  The sun's rays are concentrated at this latitude, heating moist air which rises and leads to heavy rainfall, with little seasonal variation.

  
  

  This creates the perfect conditions for evergreen rainforest.

  
  

  Many species here - over half the world's species of plants and animals.

  
  

  Very quick nutrient cycle - soils are nutrient poor but there is a thin layer of organic matter on the top of soils that makes plants very productive
• Tundra

  Found in the Arctic Circle, where Sun's rays have little strength. Temperatures are below freezing for most of the year.

  Permafrost.

  Only tough, short grasses can survive, often in waterlogged conditions (due to surface ice thawing). No trees

  High latitudes

  Harsh, cold winters + short summers.

  Low precipitation

  Short growing season
• Temperature grasslands

  Short tussock and feather grasses dominate the landscape between 40° and 60° north of the Equator, in drier centres of continents away from the sea.

  More variation in temperature (cold winters, hot summers) and less rainfall.
• Savannah Grasslands

  Conditions are dry for half of the year, due to the movement of the Hadley cell. Seasonal dryness limits the growth of trees.

  
  

  Precipitation is seasonal - distinct wet and dry seasons
• Deciduous Forest

  Higher latitudes - in western Europe and east coasts of Asia, North America and New Zealand.

  The sun's rays are weaker, so the trees shed leaves in the cooler, darker winters.

  Four distinct seasons
• Deserts (hot desert)

  Found close to the tropic of cancer and tropic of capricorn.

  Sun's rays are highly concentrated at this low latitude. Combined with the dry air, this brings arid desert conditions.

  Precipitation is low.

  Temperature is hot in the day and cold at night.
• Coniferous Forest (Taiga/Boreal)

  Found 60° North where winter temperatures are extremely cold due to lack of insolation. Due to Earth's tilt, there is no sunlight for some months of the year at high latitudes.

  Coniferous trees have evolved needle leaves that reduce moisture and heat loss during the cold, dark winter months.

  Winters = cold and dry

  Summers = mild and moist