3.5 Energy transfers in between organisms Flashcards
What is Gross Primary Production (GPP)?
The chemical energy store in plant biomass, in a given area or volume.
In other words, the rate at which energy is incorporated into organic matter by plants in a given area in a given time.
What is the unit for GPP?
KJ m-2 year-1
What is Net Primary Production?
refers to the amount of energy available to herbivores in the plant’s biomass after plant respiratory losses
What is the equation to work out NPP?
GPP - R
(R represents respiratory losses to the environment.)
What is the equation to work out the net production of consumer (N)?
N=I-(F+R)
(F represents chemical energy lost to environment through faces and urine)
(I represents chemical energy stored in ingested food)
Identify the leaf cells which are primarily responsible for photosynthesis and how the structure of these cells act to reduce the amount of light that can pass through the leaves?
Palisade mesophyll cells are tightly packed to trap as much light as possible.
The animals that humans raise are usually herbivores and not carnivores. Explain why
Energy is lost to the environment at each trophic level of a food chain through respiration and the excretion of urine and the egestion of faces, and this reduces the chemical energy store in biomass that is available to other organism. By raising herbivores, which are found immediately after the producers, the number of trophic levels is reduced meaning the biomass will not have decreased by as much and there is a greater mean energy value per kg available to humans for consumption.
How can the efficiency of energy transfer be increased?
By reducing the number of trophic levels in a food chain.
OR
By reducing respiratory losses within a human food chain.
What does the use of fungicides, herbicides and pesticides do?
They increase productivity by decreasing the energy expend in fighting infections, the loss of biomass or competition.
Why would natural predators eg ladybirds be introduced into an environment?
To eat the aphids, and this form of biological control means crops loose less biomass and this increases productivity.
What does the Haber process produce that will be helpful to plants?
Ammonium nitrates as plants need the nitrogen in nitrates to synthesize amino acids and nucleic acids.
What do fertilizers provide plants with?
Minerals needed for growth, preventing these minerals from acting as a limiting factor. This means the the efficiency of energy conversion is increased.
What is an example of an organic fertilizer?
Manure
How many stages are there in the Nitrogen Cycle?
There are 4 main stages and each involve specific saprobiont microorganisms.
Saprobiont= decomposers that covert nitrogen compounds into NH3.
State and describe the first step of the nitrogen cycle
Nitrogen Fixation
Carried out by bacteria in soil by symbiotic bacteria in root nodules of leguminous plants and by blue green bacteria in aquatic systems.
Conversion of atmospheric nitrogen to organic nitrogen containing molecules eg amino acids. etc N2 -> NH4OH
Lightning: (atmospheric fixation) high temps break nitrogen bonds and fix it to oxygen to make nitrogen oxides.
Haber proce
