Ecology

• An ecosystem is the interaction of a community of living organisms with the non-living parts of their environment
• 4 levels of organisation

  Individual organism: a single member of a species

  Population: a number of individuals of the same species living in the same area at the same time

  Community: multiple populations of different species living and interacting in the same area

  Ecosystem: the interaction of a community of living organisms with the non-living parts of their environment
• Competition: The struggle for the same limited resources between a group of organisms.

  Can be between members of the same species or between members of different species
• Adaptation: If an organism has certain features, behaviours or other characteristics that help it to survive and reproduce in its habitat, its said to be adapted to its habitat
• Examples of ecosystems

  • A garden pond
  • A woodland
  • A coral reef
  • A desert
• Interactions within an ecosystem

  In order to survive and reproduce, organisms need certain resources from their surroundings

  This means members of a species will often interact with members of its own species or other species

  Examples of these interactions:

  • Predators eating prey
  • Herbivores eating plants
  • Plant species being pollinated by bees
• Examples of competition in Plants

  • Light - photosynthesis in order to get energy for growth
  • Space - require space above soil so leaves can absorb maximum sunlight, and under soil so leaves can absorb water and mineral ions
  • Water from soil- essential for photosynthesis and plant growth
  • Mineral ions from soil - such as nitrate ions for making proteins and magnesium ions for making chlorophyll
• Examples of competition in animals

  • Food - provides energy required for growth and reproduction
  • Mates- to produce offspring
  • Territory - providing animals with shelter, food, water and mates
• Interdependence 


  Within a community, each species depends on other species for food, shelter, pollination and seed dispersal

  If one species is removed it can affect the whole species - interdependence

  A stable community is one where all the species and environmental factors are in balance so that the population sizes remain fairly constant