energy transfer and productivity Flashcards
how much sunlight do plants absorbb
between 1-3 %
why cannot plant take in all the sunlight
over 90% of the sun light is reflected back into space because of dust and clouds
not all wavelength of light can be absorbed
light may not fall on a chlorophyll molecule
low c02 levels may limit photosyynthesis
what is gpp
gros primary production it is the energy store in plant biomass in a given area at a given time
what percentage of gpp is used and what is the remaining used for
only 20-50% is used for respiration, the chemical energy store remaining is called the net primary productivity
what is npp and how is npp calculated
the remaining chemical energy stored in a plant after respiratory loses to the environment has been accounted for npp= gpp- respiratory losses
why is there low energy transfer at each stage
as not all the organism is consumed
some parts are consumed but nt digested
some of the energy is lost in excretory materials
some energy lost to the environment by heating to keep warm
why do most food chains only have four or five levels
energy loss at each stage as a result of excretion or respiration
because insufficient energy is available to support a large enough breeding population at trophic layers higher than these
what happens to the total mass as you go higher up the trophic levels
the total mass of organisms in particular place decreased and the total amount of energy is less as you move up the chain
when can we get 6-7 trophic layers when
when cold blooded animals and many producers so a larger gpp therefore a larger npp
how do we work out npp in animals
npp= I - (f+r)
what do these letter stand for
I stands for the chemical energy in ingested food
f stands for chemical energy lost in feaces and r stands for the chemical energy lost in respiration
what is primary and secondry productivity
amount of energy accumulated in the producer or consumer which is available for the next trophic layer
