B9a

• What’s a community?

  All the different organisms living in an area
• What is a trophic?

  a feeding level in a food chain
• What does each arrow on a food chain represent?

  Energy transfers
• How do you work out the estimated population size?

  (Total area / area of quadrat) x average number of organisms counted
• how do you figure up the estimated population size (practical)?

  ~place a tape measure in the area to be investigated

  ~use a random generator to get co ordinates

  ~use the tape measures and put the quadrat at that co ordinate

  ~count the number of organisms in the quadrat

  ~repeat multiple times (eg 10) and take an average

  ~use the equation and get an estimate
• What’s a transect?

  A straight line that cuts through a habitat to study the distribution and abundance of organisms
• What’s a line transect?

  A measuring tape is laid out in a straight line, the organisms touching the line recorded at equal distances. This method only measures which species are present and not their abundance
• What’s a belt transect?

  A measuring tape is laid out in a straight line, and quadrats are placed at regular intervals along the tape. The abundance of each species in each quadrat is recorded.
• What’s the advantages of a pyramid of numbers?

  ~simple to make and read

  ~good for comparing populations
• what are the disadvantages for a pyramid of numbers?

  ~large numbers lead to inaccurate pyramids

  ~doesn’t account for the size of the animals
• what are the advantages for pyramids of biomass?

  ~usually in a pyramid shape

  ~takes size into account
• What are the disadvantages for a pyramid of biomass?

  ~organisms have to be killed

  ~only sample data used
• how do you work out the effiency of energy?

  Energy transferred to biomass / total energy supplied to organism
• How is lichen an indicator species for air quality?

  The amount of lichen in an area tells you how much sulfur dioxide is in the air.
• How is black spot fungus an air quality indicator?

  If there is no black spot fungus on a rose then there is loads of sulfur dioxide in the air
• What’s an indicator for low level water pollution?

  Mayfly nymph
• What an indicator for high level pollution in water?

  Worm (tubifex)
• What’s the disadvantage for using indicator species for water pollution levels?

  Don’t know exact level as those that can live in high pollution concentrations can also live in lower concentrations
• What causes eutrophication?

  When fertillisers and sewage are washed into rivers and lakes. This leads to the death of aquatic life
• Describe how the overuse of nitrate fertiliser can cause eutrophication

  ~fertilisers used by farmers on crops to increase growth

  ~when it rains the fertilisers are washed into rivers and lakes

  ~this then fertilisers the algae causing it to grow excessively

  ~the algae blocks out the light, causing the plants underwater to suffocate as they can’t photosynthesise

  ~the decomposed bacteria rapidly reproduces and eats all the dead matter

  ~the bacteria use too much O2, and with no plants the convert the CO2 to O2, the fish suffocate and die
• What adaptations do tape worms have?

  ~hooks to help them attach to the intestinal wall

  ~a flat body to allow them to absorb nutrients without needing a digestive system
• What adaptions do head louse have?

  ~sharp mouth parts to pierce skin and suck blood

  ~sharp claws to grip onto hair and skin
• What’s parasitism?

  When a parasite feeds off a host organism, causing them harm
• What’s mutualism?

  A biological relationship where both parties benefit
• How are sea anemones and clown fish an example of mutualism?

  ~clown fish hide in the sea anemones stinging tentacles for protection

  ~clown fish provide nutrients in their faeces, which help the sea anemones to grow
• How is algae and coral animals an example of mutualism?

  ~coral animals allow algae to grow inside them, providing protection

  ~algae provides food for the coral animals when they photosynthesise
• How is nitrogen-fixing bacteria and pea plants an example of mutualism?

  ~nitrogen fixing bacteria are protected in the nodules of the plant

  ~pea plants receive nitrate, which it needs to grow
• What are the pros of fish farming?

  ~provides food

  ~cheaper

  ~stops overfishing in rivers and seas
• What are the cons of fish farming?

  ~impacts animal welfare as are kept in small spaces

  ~food and faces damage other organisms

  ~diseases spread easily
• Why do humans do reforestation?

  ~reduces air pollution, green house effect and global warming

  ~helps recovery of natural habitats

  ~restores food chains/ webs

  ~improves health and well-being of people in the area
• What are the advantages of biofuels?

  ~carbon neutral

  ~less fossil fuels used

  ~renewable
• What are the disadvantages to biofuels?

  ~use a lot of land which could be used for farming food

  ~weather dependent