4.7.1.1 communities

• what is a community?

  made up of the populations of different species of animals and plants that are all independent in a habitat
• what things do species rely on each other in a community?

  food, shelter, pollination and seed dispersal
• what is an ecosystem?

  a community of organisms (biotic) interacting with the abiotic elements of their environment
• what do organisms require to survive and reproduce?

  a supply of materials from their surroundings and from the other living organisms there
• why is the Sun necessary?

  it’s the source of the energy that is transferred through ecosystems within the chemical bonds that make up the organisms
• what materials are important and why?

  carbon, nitrogen and water - they are recycled through the living world in processes where microorganisms play a major part
• what do plants compete for in a habitat?

  light and space, and for water and mineral ions from the soil
• what do animals compete for in a habitat?

  food, mates and territory
• what happens if a species is removed from an ecosystem and what is this called?

  it can affect the whole community - called interdependence
• what is a stable community?

  where all the species and environmental factors are in balance so that population sizes remain fairly constant