Ecology

• Individual


  Part of a species, lives in its habitat within a population
• Community


  Many different populations interact in the same habitat
• Ecosystem


  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
• Competition between plants


  • For light, space, water and mineral ions
• Competition between animals


  • For space, food, water and mating partners
• Interdependence


  Organisms in a community depend on other organisms for vital services like food, shelter and reproduction
• 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
• Stable communities


  • Tropical rainforests, oak woodlands, coral reefs
• 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
• Types of adaptations


  • Structural
  • Behavioural
  • Functional
• Extremophiles


  Organisms that live in environments with extreme conditions like high temperatures, pressures or salt concentrations
• Adaptations for different scenarios

  • Cold climates: Smaller surface area to volume ratio, lots of insulation

  Dry climates: Adaptations to kidneys, active in early morning/evening, larger surface area ratio

  Plant adaptations: Curled leaves, extensive root systems, waxy cuticle, water storing tissue
• Producer


  Photosynthetic organism that makes glucose through photosynthesis
• Primary consumer


  Organism that eats the producer
• Secondary consumer


  Organism that eats the primary consumer
• Tertiary consumer


  Organism that eats the secondary consumer
• Transects and quadrats


  Tools 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


  CO2 is removed from the air in photosynthesis and returned to the air through respiration and combustion
• Water cycle


  Water evaporates, forms clouds, precipitates, and runs into seas to repeat the cycle
• Factors affecting rate of decomposition

  • Temperature
  • Water
  • Availability of oxygen
• Compost


  Produced when biological material decays, used as a natural fertiliser
• Methane gas


  Produced by microorganisms decomposing waste anaerobically, can be burnt as a fuel
• Environmental changes affect the distribution of species in an ecosystem
• 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
• Human activities negatively affecting biodiversity

  • Using more land for houses, farming, shops, roads and factories

  Pollution killing plants and animals

  Using up raw materials quicker than they are being produced
• Humans are becoming less dependent on each other for things such as food and shelter
• The future of humans on Earth depends on maintaining biodiversity – for example for food and new medicines
• The impact of our activities is getting bigger as the population is increasing, as more resources are being used and more waste is being produced
• Negative impacts of human activities on biodiversity

  • More land is being used for houses, farming, shops, roads and factories, which destroys habitats
  • Pollution kills plants and animals
  • Sewage, fertiliser and toxic chemicals pollute the water
  • Smoke and acidic gases pollute the air
  • Landfill and toxic chemicals can result in the pollution of the land
  • We are using up raw materials quicker than they are being produced
• Humans have only recently tried to reduce their impact
• Land Use


  Humans take up land and therefore reduce the number of habitats for animals and plants by building, quarrying (cutting into ground to obtain stone and other materials), farming and dumping waste