Ecosystems

• Ecosystem

  All the biotic (living) parts (e.g. plants and animals) and the abiotic (non-living) parts (e.g. soil and climate) of an area
• Organisms in ecosystems

  • Producers
  • Consumers
  • Decomposers
• Producer

  An organism that uses sunlight energy to produce food
• Consumer

  An organism that gets its energy by eating other organisms, either producers or other consumers
• Decomposer

  An organism that gets its energy by breaking down dead material, e.g. dead producers and dead consumers
• Nutrient Cycle

  1. Plants absorb nutrients from the soil and use them to grow

  2. Animals eat plants, taking in the nutrients they contain

  3. When dead material decomposes, nutrients are released into the soil

  4. The nutrients are then taken up from the soil by plants
• Nutrient cycling

  The transfer of nutrients through the ecosystem
• Food Chains

  Show what eats what
• Food Webs

  Show lots of food chains and how they overlap
• Each part of an ecosystem depends on other parts, e.g. consumers may depend on producers as a habitat and a source of food
• If one part changes

  It affects all the other parts that depend on it
• The climate in an area determines what type of ecosystem forms
• Major types of global ecosystems

  • Tundra
  • Boreal Forest
  • Grassland
  • Temperate Deciduous Forest
  • Tropical Rainforest
  • Hot Desert
  • Polar
• Tundra

  • Found at high latitudes above 60° N, very cold winters, brief summers, little rainfall, hardly any trees, vegetation includes moss, grasses and low shrubs, layer of permanently frozen ground called permafrost
• Boreal Forest (Taiga)

  • Found between 50-60° N, cold and dry winters, mild and moist summers, trees are coniferous and evergreen
• Grassland

  • Savannah grasslands found between the tropics, distinct dry and wet seasons, mostly grasses with a few scattered trees
  • Temperate grasslands found at higher latitudes, more variation in temperature and less rainfall, only grasses
• Temperate Deciduous Forest

  • Found mainly in the mid-latitudes, four distinct seasons, warm summers, relatively mild winters, rainfall all year round, deciduous trees lose their leaves in winter
• Tropical Rainforest

  • Found around the equator between the tropics, hot and wet all year round, lush forest with dense canopies of vegetation forming distinct layers
• Hot Desert

  • Found between 15° and 35° north and south of the equator, little rainfall, very hot during the day and very cold at night, shrubs and cacti sparsely distributed in the sandy soil
• Polar

  • Found around the north and south poles, very cold, icy and dry, not much grows at all, remain dark for several months each year so the growing season is very short