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• Ecosystem


  A system in which organisms interact with each other and with their environment
• Components of an ecosystem

  • Biotic (living organisms - plants, animals, birds)
  • Abiotic (non-living elements - water, soil, air)
• Producer


  A plant that can produce its own food through photosynthesis. They are the start of a food chain.
• Consumers


  Organisms that feed on plants or animals to get energy
• Predator


  The animal or bird at the top of the food chain/web
• Decomposers


  Organisms like bacteria or fungi, that break down dead plant and animal matter, returning nutrients to the soil
• Food chain


  A simple flow chart that shows the different organisms that feed on each other. It shows the direct transfer of energy.
• Food web


  A complex network / hierarchy of interlinked food chains. It shows the producers and consumers in a whole ecosystem.
• UK Example: Pond Ecosystem

  • Algae (producer) - Larva - Great Diving Beetle - Stickleback fish - Perch (Predator)

  
• Plants take in nutrients to build into new organic matter. Nutrients are taken up when animals eat plants and then returned to the soil when animals die and the body is broken down by decomposers.
• Litter


  The surface layer of vegetation, which over time breaks down to become humus
• Biomass


  The total mass of living organisms per unit area
• If there is a decline in the predator

  Greater population of the animal it eats
• If the primary consumer declines

  Greater population of the producer and less of the secondary consumer
• If the producer dies


  Decline in the whole ecosystem
• Global Biomes (large scale ecosystems)

  • Tropical Rainforests
  • Tropical grasslands (savanna)
  • Deserts (hot)
  • Deciduous forests
  • Coniferous forests
  • Tundra
• Tropical Rainforests


  • Along the equator (Asia, Africa / South America), 6% of earth's surface, 25°C - 30°C and over 2000 mm a year
• Rainforest Nutrient Cycling


  The hot, damp conditions on the forest floor allow for the rapid decomposition of dead plant material. So lots of nutrients are then absorbed by plant roots. If vegetation is removed, the soils quickly become infertile, dry and soil erosion occurs.
• Tropical grasslands (savanna)


  • Between equator and tropics, 20 - 30°C and between 500 - 1500 mm of rain per year, Wet and dry seasons
• Deserts (hot)


  • Tropics (Sahara and Australia), Over 30°C and less than 300 mmm per year rain, 20% of land's surface
• Deciduous forests


  • Higher latitudes (W Europe, N America, New Zealand), 5 - 20°C and between 500 - 1500 mm rain per year, 4 distinct seasons, Lose leaves in the winter to cope with the cold
• Coniferous forests


  • 60°N (Scandinavia / Canada), Cone bearing evergreen trees, No sunlight for part of the year
• Tundra


  • Above 60°N (Arctic Circle), Less than 10°C and less than 500mm per year rain, Cold, icy and dry means 2 month growing season
• Layers of the Rainforest

  • Emergent Layer
  • Canopy Layer
  • Understory or Undercanopy Layer
  • Forest floor (or shrub layer)

  
• Emergent Layer


  • The tallest trees, growing up to and over 40 metres

  
• Canopy Layer


  • A denser layer of trees around 30 metres high. It receives 70% of sunlight and 80% of life is found here. Trees compete for sunlight here for photosynthesis
• Understory or Undercanopy Layer


  • Up to 20 metres high, usually younger trees
• Forest floor (or shrub layer)


  • Dark, damp and humid, very little light, about 2%, small shrubs and ferns

  
• Buttress roots


  • Wide, thick, tall roots to support the tall trees so they can grow high to compete for sunlight for photosynthesis
• Drip tip leaves


  • Pointed end of a lead, acts like a funnel, removing excess rainwater, preventing the leaf from breaking

  
• Epiphytes


  • Plants that grow on branches or trunks to get nutrients from the air and water and to access sunlight for photosynthesis
• Other plant adaptations


  • Thick waxy leaves
  • Lianas (vines)
  • Tall straight trees
• Sloths


  • Brown light fur for camouflage, Long arms to climb and hang from trees, Slow moving so not seen by predators

  
• Toucan


  • Short wings to manoeuvre around trees, Curved keratin beak to break through nuts and fruit

  
• Red Eyed Tree Frog


  • Webbed feet for jumping and landing, Bright coloured skin to warn off predators

  
• Biodiversity


  The variety of life (plants and animals) in a particular ecosystem or habitat. 2% of land surface, over 50% of all plants and animals
• Small changes to biotic and abiotic factors can have serious knock-on effects in the tropical rainforest
• Biomass is the largest nutrient store, and the biggest transfer is from soil to biomass
• Fertility is quickly lost from the soil if trees are cut down in the tropical rainforest
• Thick litter layer in the tropical rainforest. Rapidly breaks down due to climate