Biology Ecology

• Community


  Many different populations interact in the same habitat
• Ecosystem


  The interaction of a community with non-living (abiotic) parts of the environment
• Organisms


  • Adapted to live in the conditions of their environment
• Competition


  Can be within a species or between different species
• Things plants may compete for

  • Light
  • Space
  • Water
  • Mineral ions
• Things animals may compete for

  • Space
  • Food
  • Water
  • Mating partners
• Interdependence


  How organisms in a community depend on other organisms for vital services
• Interdependence


  • Birds take shelter in trees
  • Flowers are pollinated with the help of bees
• The removal or addition of a species to the community can affect the populations of others greatly, as it changes prey or predator numbers
• Stable community


  Where all the biotic (living) and abiotic (non-living) factors are in balance, resulting in population sizes remaining roughly constant
• Abiotic factor


  A non-living factor
• Abiotic factors that can affect a community

  • Light intensity
  • Temperature
  • Moisture levels
  • Soil pH and mineral content
  • Wind intensity and direction
  • Carbon dioxide levels
  • Oxygen levels for aquatic animals
• Biotic factor


  A living factor
• Biotic factors that can affect a community

  • Food availability
  • New predators
  • New pathogens
  • Competition
• Adaptation


  Allows organisms to survive in the conditions where they live
• Types of adaptations


  • Structural
  • Behavioural
  • Functional
• Extremophiles


  Organisms that live in environments with extreme conditions
• Extremophiles


  • Bacteria which live in deep sea vents where the pressure is very high
• Examples of adaptations for different scenarios

  • Cold climates
  • Dry climates
  • Plant adaptations
• Producer


  Photosynthetic organisms (usually a green plant or algae) that make glucose through photosynthesis
• Primary consumer


  Organisms that eat the producers
• Secondary consumer


  Organisms that eat the primary consumers
• Tertiary consumer


  Organisms that eat the secondary consumers
• Transect


  Tool used to work out the distribution and abundance of species in an ecosystem
• Quadrat


  Tool used to work out the distribution and abundance of species in an ecosystem
• A stable community will show population cycles between the predators and prey
• Carbon cycle


  The cycling of carbon through an ecosystem
• Water cycle


  The cycling of water through an ecosystem
• Factors affecting decomposition rate

  • Temperature
  • Water
  • Availability of oxygen
• Compost


  Biological material that has decayed, used as a natural fertiliser
• Methane gas


  Produced by microorganisms decomposing waste anaerobically, can be burnt as a fuel
• Biogas generators


  Used to produce methane, require a constant temperature of 30 degrees
• Investigating the effects of temperature on decay

  1. Make a solution of milk and phenolphthalein indicator

  2. Add sodium carbonate to make it alkaline

  3. Place in water bath at specific temperature

  4. Add lipase enzyme and time how long it takes for pink colour to disappear

  5. Repeat at different temperatures
• Environmental changes affect the distribution of species in an ecosystem
• Examples of environmental changes

  • Temperature changes
  • Water availability changes
  • Atmospheric gas composition changes
• Biodiversity


  The variety of different species of organisms on Earth or within an ecosystem
• High biodiversity means the ecosystem will be stable
• Many human activities are having a negative effect on biodiversity
• The future of humans on Earth depends on maintaining biodiversity
• Human activities negatively impacting biodiversity

  • Using more land for houses, farming, shops, roads and factories
  • Pollution (sewage, fertiliser, toxic chemicals, smoke, acidic gases)
  • Using up raw materials quicker than they are being produced