Energy transfer and productivity Flashcards
Why is most of the suns energy not converted to organic matter by photosynthesis?
90% of suns energy is reflected by cloud or dust or absorbed by atmosphere
Not all wavelengths of light can be absorbed
Light may not fall on chlorophyll molecule
Low CO2 may be a limiting factor
What is the definition of Gross primary production?
The total quantity of the chemical energy store in a plants biomass in a given area or volume in a given time
What is net primary productivity?
Chemical energy store left after energy losses from respiration are accounted for
Equation for net primary production (NPP)
Net primary production = Gross primary production - respiratory losses
NPP = GPP - R
Why may not all energy be transferred at each trophic level in a food chain?
Some organism is not consumed
Some parts are consumed but cannot be digested so are excreted
Some energy lost in excretory material (urine)
Some energy loss as heat from respiration
What is the formula for the net production of consumers?
N = I - (F+R)
N = net production
I = Chemical energy store of ingested food
F = Energy lost in faeces and urine
R = Energy lost in respiration
What can the inefficiency of energy transfer between trophic levels tell us?
Most food chains will have 4/5 trophic levels
Biomass is lower at higher trophic levels
Less energy available at each level going up the food chain
What equation can you use to calculate efficiency of energy transfer?
Percentage efficiency = (Energy available after transfer / energy available before transfer) X100
