Energy and ecosystems Flashcards
How do plants use the sugars from photosynthesis?
As respiratory substrates
Synthesis biological molecules
What is biomass?
Total dry mass of carbon in a given area over a specific time
Measured using calorimetry (gm-2 for area)
Define gross primary product (GPP)
Total chemical energy in a plant within a given area
Define net primary productivity (NPP)
Total chemical energy available for plant growth, reproduction and energy transfer to other trophic levels after respiratory losses
Give the equation that links GPP and NPP
NPP = GPP - R (respiratory losses)
Why does biomass decrease along a food chain?
Energy lost through excretion
Energy lost to surroundings as heat
Not all the organism is consumed
Define primary + secondary productivity
Rate of primary / secondary production
Biomass in a specific area over a given time period
Why are food chain lengths limited?
Energy is lost at each trophic level
Insufficient energy to support higher levels
Explain the significance of phosphorus to living organisms
Plants convert inorganic phosphate into biological molecules
e.g. ATP, NADP, DNA
Phosphorus passed to consumers via feeding
Name the 4 main stages of the nitrogen cycle
- Nitrogen fixation
- Ammonification
- Nitrification
- Denitrification
