ecosystems

• an ecosystem is a natural system made up of biotic and abiotic things
• a global system is called a biome
• a producer always starts at the top of the food chain
• examples of producers

  green plant

  grass
• producers make their own food by photosynthesis
• a primary consumer lives off producers
• a secondary consumer lives off other animals
• a tertiary consumer lives off animals larger in size
• a food chain shows how energy passes through an ecosystem
• what's the importance of bacteria and fungi

  bacteria and fungi decompose things like leaf matter. this becomes nutrient is the soil for plants to absorb
• what are natural changes that effect the ecosystem

  1. extreme weather
  2. climate change
  3. forest fires
• examples of natural changes to the ecosystem

  1. 1987-the great storm felled 15 million trees
  2. 1976-southern england 18 month drought, trees dead
• what are human changes that effect the ecosystem

  1. deforestation- soil erosion and loss of fertility
  2. agriculture
  3. eradication of species
  4. human induced climate change
• in europe and USA they have killed wolves and bears so rabbit and deer population can increase
• re-wilding in Yellowstone national park

  1. more willow
  2. wolves introduced which eat elk meaning more vegetation