productivity Flashcards
what does the productivity of an ecosystem depend on ?
- abiotic and biotic factors
what will maximise the rates of photosynthesis ?
- plenty of:
- water
- light
- green plants
what will maximising the rate of photosynthesis result in ?
- more carbohydrates being produced in the plants
what does GPP stand for ?
- gross primary productivity
what is meant by GPP ?
- the chemical energy store in a plant biomass in a given area or volume , in a given time
- total energy resulting from photosynthesis
what dos NPP stand for ?
- net primary productivity
what is meant by net primary productivity (NPP) ?
- the chemical energy store in a plant biomass after respiratory losses to the environment have been taken into account
state the equation that links NPP, GPP and R
NPP = GPP - R
what does the calculated NPP tell you ?
- it tells you the energy left over that is available to the plant to create new biomass and therefore available to the next trophic level in the ecosystem such as herbivores or decomposers
how can the net production of consumers (N), such as animals, be calculated ?
N = I - (F + R)
N = energy in biomass for growth
I = the chemical energy stored in ingested food
F = chemical energy lost to the environment as faeces and urine
R = respiratory losses
why is not all of the energy available to consumers ?
- not all of the organism available to the consumer is ingested / eaten (bone, roots)
- some of the biological molecules are not digestible (cellulose, connective tissues, fibres)
- much of the energy taken in by the consumer is lost to the environment as respiratory losses or through excretion of urine
why is some energy not available to the plant / producer?
- light is at the wrong wavelength
- light may have been reflected
- light energy could have been transmitted
where does the energy in indigestible material go to ?
- decomposers such as fungi or bacteria
what are these decomposers called ?
- saprobionts
