section 8 - ecology

• Ecosystem


  All of the living organisms (biotic) and their environment (abiotic)
• Habitat


  Place an organism lives
• Population


  All the organism of one species in a habitat
• Community


  All the different species in a habitat
• Investigate population size


  1. Throw the quadrat randomly three times

  2. Count and record in how many squares the organism is in

  3. Calculate the mean number
• Biodiversity


  Measure of the variety of different species in an ecosystem
• Measure biodiversity


  Use quadrat but instead of randomly place is systematically along a transect
• Trophic levels


  • Producers: plants
  • Primary consumer: eats producer
  • Secondary consumer: eats primary consumer
  • Tertiary consumer: eats secondary consumer
• Herbivore


  Animal that eats plants only
• Carnivore


  Animal that eats animals only
• Omnivore


  Animal that eats plants and animals
• Pyramid of numbers


  The size of each block is related to the number of organisms. Producer goes at the base, followed by each trophic level
• Pyramid of biomass


  Biomass is the total number of living material in an organism
• Pyramid of energy transfer


  Shows how energy is transferred between trophic levels. Only 10% is passed at each trophic level
• Energy loss


  • Organism can't digest all of the organism it eats
  • Some material is egested
  • The organism will use some of the energy gained for MRSGRENC. Therefore, it won't all be passed on to the next organism
• Carbon cycle


  Cycle within ecosystems

  
• Increased carbon dioxide in the atmosphere


  • Global warming/greenhouse effects
  • Rising sea levels
  • Climate change
  • Extinction
• Plants limit increase of carbon dioxide


  Absorb carbon dioxide in photosynthesis

  
• Nitrogen cycle


  Cycle within ecosystems

  
• Greenhouse effect


  The sun radiates heat and some gets trapped by the greenhouse gases in the Earth's atmosphere
• Greenhouse gases


  • Carbon dioxide: from burning fossil fuels in factories, power stations, houses and vehicles
  • Nitrous oxide: from car fumes and fertilisers
  • Methane: from cattle and landfills
  • CFCs: from aerosols and fridges
• Global warming


  • Change in global weather patterns
  • Polar ice melting causing a rise in sea levels
  • Could change the environment causing organisms to become extinct
• Acid rain


  Sulphur dioxide dissolves in rain water to make sulphuric acid which forms acid rain
• Acid rain


  • Kills trees by damaging leaves and stops minerals being absorbed from the soil
  • Kills organisms in lakes that are sensitive to pH

  
• Eutrophication


  Untreated sewage, nitrates from fertilisers and pesticides have cause damage

  
• Effects of deforestation


  • Less evapotranspiration: makes local climate drier
  • Leeching: the dry soil causes rain water to run off it with minerals, causing infertile soil
  • Soil erosion: soil gets washed away as there are no plants to hold it in place
  • More carbon dioxide: less trees photosynthesizing and removing carbon dioxide and making oxygen

  
• Advantages of deforestation


  • Land for farming, building and road
  • Wood for building and fuel
• Disadvantages of deforestation


  • Loss of habitat
  • Affects biodiversity/food chain
  • Soil erosion/leeching
  • Affects carbon dioxide level/global warming
• Extinction causes


  • Global warming
  • Disease
  • Hunting
  • Deforestation