5.3 Energy Transfer in Ecosystems

Question 1

What is the measurement for biomass

Answer 1

Mass of carbon (Dry mass)

Question 2

How can biomass be estimated

Answer 2

Calorimetry

Question 3

What is productivity measured in, and why are those measurements used

Answer 3

• kJ / ha / year
• Per hectare standardises results, for a valid comparison, as ecosystems vary in size
• Per year standardises results, for a valid comparison, as different seasons impact productivity

Question 4

Equation for energy transfer in PLANTS

Answer 4

NPP = GPP - R

Question 5

What is R in NPP = GPP - R

Answer 5

Energy lost in respiration

Question 6

What is the energy available to the next trophic level for plants

Answer 6

NPP

Question 7

Where does GPP energy come from

Answer 7

Photosynthesis

Question 8

Equation for energy transfer in CONSUMERS

Answer 8

N = I - (F + R)

Question 9

What is N in N = I - (F + R)

Answer 9

Energy available for **growth and reproduction **

Question 10

What is I in N = I - (F + R)

Answer 10

Energy from ingested food

Question 11

What is (F+R) in N = I - (F + R)

Answer 11

Energy lost as faeces and urine, and energy lost in respiration

Question 12

In what ways can farmers increase food production through energy transfers

Answer 12

• Simplify food webs and chains to reduce the number of trophic levels
• Reduce respiratory losses by restricting movement, and using heated barns
• Increase GPP in greenhouses (e.g lamps and heaters)

Question 13

Why is not all of the light energy avaliable used in photosynthesis

Answer 13

• Light reflected off chlorophyll
• Light wrong wavelength to be absorbed by chlorophyll
• Light misses chloroplast
• Carbon dioxide concentration or temperature is the limiting factor