energy and ecosystems

• What is each stage in a food chain called?

  A trophic level
• What do the arrows in a food chain represent?

  The flow of energy and matter
• What do food chains always start with?

  Photosynthetic producers
• Who eats the producers in a food chain?

  Primary consumers
• What breaks down dead matter in an ecosystem?

  Decomposers
• What are the trophic levels in the given food chain: GRASS, GRASSHOPPER, TOAD, HAWK, SNAKE?

  • 1st Trophic Level: Grass (Producer)
  • 2nd Trophic Level: Grasshopper (Primary Consumer)
  • 3rd Trophic Level: Toad (Secondary Consumer)
  • 4th Trophic Level: Hawk (Tertiary Consumer)
  • 5th Trophic Level: Snake (Quaternary Consumer)
• What type of consumer is a hawk in the food chain?

  A tertiary consumer
• What is the flow of energy and biomass in a food chain?

  It decreases as you move up the trophic levels
• What is the general term for bacteria and fungi that break down dead organisms?

  Decomposers
• What does Gross Production refer to?

  Total amount of energy converted into organic matter by photosynthesis
• What is Respiratory Loss?

  Amount of energy used in respiration
• What is Net Production?

  Total amount of energy stored by plants
• What is the equation for Net Production?

  $\text{Net Production} =$$\text{Gross Production} - \text{Respiratory Loss}$
• What are the units for Net Production?

  kJ m^-2 year^-1
• Why is most of the sun's energy not converted to organic matter?

  Because it is lost in various processes
• How do you calculate missing values in energy production data?

  By using the equations for GPP, respiration, and NPP
• What does the energy loss in food chains imply about their structure?

  They typically have only 4-5 trophic levels
• What do intensive farmers do to limit energy loss?

  They limit movement and keep sheds warm
• What is the formula for consumer production?

  $N =$$I - (F + R)$
• What does 'I' represent in the consumer production formula?

  Chemical energy in ingested food
• What does 'F' represent in the consumer production formula?

  Energy lost as faeces, urine, and undigested food
• What does 'R' represent in the consumer production formula?

  Energy lost through respiration
• What does the energy loss in food chains mean for the total energy stored in biomass?

  It decreases as you move up the trophic levels
• What is the efficiency of energy transfer formula?

  $\text{Efficiency} =$$\left(\frac{\text{Energy before transfer}}{\text{Energy after transfer}}\right) \times 100$
• How do you calculate the percentage efficiency transfer between trophic levels?

  By using the efficiency formula with the energy values
• What happens to energy transferred to humans if they eat Smelt directly?

  It increases the energy available to humans
• What is meant by net primary production?

  The total energy stored by plants after accounting for respiration
• Why is net primary production higher in tropical rainforests than in temperate deciduous woodlands?

  Due to higher sunlight and rainfall
• What is process A in the energy flow diagram?

  Photosynthesis
• What type of organisms carry out process B in the energy flow diagram?

  Decomposers
• How do you calculate the percentage efficiency of energy transfer between primary producers and primary consumers?

  By using the given efficiency percentage and energy values
• Why is energy transfer more efficient between primary and secondary consumers than between primary producers and primary consumers?


  Because secondary consumers often consume more digestible parts
• What are the key processes in the nitrogen cycle?

  1. Ammonification
  2. Nitrification
  3. Nitrogen fixation
  4. Denitrification
• What is the role of ammonifying bacteria?

  To break down organic nitrogen compounds into ammonium
• What do nitrifying bacteria do?

  They convert ammonium ions to nitrite and then to nitrate
• What is denitrification?

  The process of converting nitrates back into nitrogen gas
• What is nitrogen fixation?


  The conversion of nitrogen gas into nitrogen-containing compounds
• What is the phosphorus cycle primarily associated with?

  Rock, soil, lakes, oceans, plants, and animals
• What are the processes involved in the phosphorus cycle?

  1. Erosion
  2. Absorption
  3. Feeding
  4. Excretion
  5. Decomposition
  6. Sedimentation
• What are mycorrhizae?

  Associations between fungi and plant roots