Energy Flow through an Ecosystem

Question 1

Photosynthetic efficiency (PE) (definition)

Answer 1

a measure of how well a plant is able is able to capture light energy

Question 2

Photosynthetic efficiency (PE) (formula)

Answer 2

Quantity of light energy incorporated into product (GPP) / Quantity of light energy falling on the plant

Question 3

What is the typical value of Photosynthetic efficiency for plants and crop plants

Answer 3

1-2%, crop plants 7-8%

Question 4

Around 60% if the light energy that falls on a plant may not be absorbed by photosynthetic pigments as…?

Answer 4

• sunlight misses leaves
• be reflected back -> green wavelength
• transmission through the leaf
• absorbed by non-photosynthetic parts

Question 5

Gross Primary Productivity (GPP) (definition)

Answer 5

rates of production of chemical energy in organic molecules by photosynthesis in a given area

Question 6

What are the units of Gross Primary Productivity (GPP)

Answer 6

KJm-2year-1

Question 7

What is the average GPP?

Answer 7

0.2kJm-2year-1

Question 8

Net Primary Productivity (NPP) (definition)

Answer 8

potential biomass available to primary consumer

Question 9

Net Primary Productivity (NPP) (formula)

Answer 9

NPP = GPP - Respiration

Question 10

What is average NPP?

Answer 10

50% of GPP