Productivity

Question 1

What is biomass?

Answer 1

Total dry mass of tissues over a given time in a specific area

Question 2

Give a possible unit for biomass

Answer 2

Mass and area/volume
Grams per metre squared
Grams per litre

Question 3

How is the biomass of organic material found?

Answer 3

Heat the organic material (must not burn) in a incubator
To evaporate off the water
Measure the mass of material
Re-heat for 24 hours
Measure the mass of material [
Continue until the mass remains constant

Question 4

Define gross primary productivity GPP

Answer 4

Total chemical energy in plant biomass within a given area/volume

Question 5

Define net primary productivity NPP

Answer 5

Total chemical energy available for plant growth and reproduction and energy transfer to other trophic levels after respiratory losses.

Question 6

Why is most of the energy in sunlight not converted into organic material?

Answer 6

Absorbed by atmosphere
Not all light falls directly on a chlorophyll molecule
Wrong wavelength to be absorbed by photosynthetic pigments

Question 7

Why does energy decrease along a food chain?

Answer 7

Energy lost in nitrogenous waste eg urine and faeces
Some of organism is not consumed
Energy lost to surrounding as heat