Energy Transfers Flashcards
1
Q
Define net primary productivity
A
The rate at which energy from the sun is converted into organic molecules making up new plant biomass
2
Q
Define gross primary productivity
A
The energy transferred to primary consumers
3
Q
Why may energy be lost at each tropic level?
A
- Undigested matter
- Respiration (exothermic, transfers thermal energy to surroundings)
- Metabolic waste products (urine/faeces)
4
Q
Define trophic level
A
Position or stage that something occupies in a food chain
5
Q
Define biomass
A
The mass of living materials in a particular place or organisms
6
Q
Describe two techniques for measuring biomass
A
- By measuring the mass of fresh material present (easy but unreliable as water mass varies)
- Or measuring the dry mass (most accurate but organisms must be killed and heated at high temps to remove water)
7
Q
How is net primary production calculated?
A
net production = gross production — respiratory losses
