Flashcards in 188.8.131.52 - Energy and Ecosystems (GPP and NPP) Deck (17)
All the organisms living in a particular area and all the abiotic conditions.
What are producers?
Organisms that make their own food - usually by photosynthesis.
What is biomass?
The chemical energy stored in the plant
Define dry mass
The mass of the organism with the water removed
What unit are typically used to measure biomass?
dry mass of tissue per unit area per time.
How do you measure dry mass?
The sample is dried in a over (low temperature). The sample is then reweighed at intervals until a constant mass is reached.
How can you estimate the chemical energy stored in biomass?
Burn it in a calorimeter. The amount of heat given off tells you how much energy is in it.
What is the unit of energy?
Joules or kilojoules
What does GPP stand for?
Gross primary production
The total amount of chemical energy converted from light energy by plants, in a given area, in a given time.
How much GPP is lost to the environment as heat when the plants respire?
Define respiratory loss?
The amount of GPP that is lost to the environment as heat when the plants respire.
How can you calculate NPP?
NPP = GPP - R
What does NPP stand for?
Net primary production
Define net primary production
The energy available to the plant for growth and reproduction. The energy is stored in the plants biomass.
Why does only 90% of the chemical stored in the consumers food transferred to the next trophic level?
Not all the food is eaten.
Some parts are indigestible.
Some is egested as faeces.
Some is lost through respiration or excretion of urine.