environment (4)

• population?all the members of one species
• community?

  all members of all species in a habitat
• habitat?

  the place where an organism lives
• ecosystem?


  the living and non-living factors of a habitat
• quadrat = wire square with 100 little squares used to count: individual species or percentage
• abiotic?

  non-living features - eg. temp
• biotic?

  living features - eg. grass
• tropic levels = producer - primary consumer - secondary consumer - tertiary consumer - quaternary consumer
• producer = makes food from photosynthesis
• food chain?


  shows what organisms eat which
• food webs?

  many food chains linked together
• pyramid of number = how many of each species
• pyramid of energy = energy of total organisms
• producers get light energy from the sun - change to chemical energy in photosynthesis
• primary consumer eats producer = breaks down biomass by digestion and uses chemical energy to sustain own biomass
• percentage efficiency of energy transfer = biomass of higher trophic level/biomass of lower trophic level x 100
• energy is gained from eating a producer - lose energy by moving, keeping warm and faeces - about 10% of energy moves up each trophic level
• eutrophication = minerals are leeched of fields and run into waterways - cause overgrowth of algae and aquatic plants - block light getting to bottom of water = causes them to die from lack of light for photosynthesis - bodies decay by decomposing bacteria that respire - use up all oxygen = kills animals and plants from lack of oxygen (anoxic water)
• fertiliser causes eutrophication - chemical mixture of broken down manure - rich with nutrients
• sewage pollutes and causes eutrophication - contains broken down urine (urea) that is rich with nutrients
• greenhouse gases = carbon dioxide, water vapour, CFCs, nitrous oxides, methane
• human causes to global warming = combustion: burning fossil fuels eg. cars - farming: methane from cows and rice paddy fields - CFCs: fridges and aerosols and effects the ozone layer
• acid rain = made by burning fossil fuels and the vapours that dissolved in the rain to produce acids - pH 5-6 = dissolves limestone
• consequences of global warming?

  ice caps melting, sea level rise, habitat loss, extinction, flooding, extreme weather, climate change, change in disease spread and migration patterns
• pyramid of biomass = the dry mass of total organism
• nitrogen cycle:

  1. decomposing bacteria feed on dead matter and release ammonium ions = ammonification
  2. nitrifying bacteria convert ammonium into nitrite ions = nitrification part 1
  3. nitrifying bacteria convert nitrite ions into nitrate ions = nitrification part 2 (can be absorbed by plants and used to make amino acids - growth)
  4. nitrates turned into nitrogen gas by denitrifying bacteria = denitrification = bad as reduces nitrate ions available for growth
  5. nitrogen fixing bacteria convert nitrogen gas into nitrogen containing compounds