Energy transfers Flashcards
Define biomass
Mass of carbon
In dry mass of tissue per given area
Suggest what you should do to ensure all water is removed from sample
Regularly weigh and Heat to 95degree
Until constant mass
Gross primary productivity
Chemical energy in plant biomass in a given area or volume
Net primary production
Chemical energy store in plant biomass after respiratory losses have been taken into account
The percentage of light energy trapped by producers is very low. Give two reasons why
Light is reflected off of leaf
Too few chloroplast
In natural ecosystems not all light falling on producers is used in photosynthesis give two reasons why
Light is reflected
Wrong wavelength of light
The biomass of primary consumers is less than the biomass of producers explain why. 4points
Loss of energy
In respiration
In excretion
Some parts are inedible
Describe and explain why the efficiency of energy transfer is different at different stages of transfer. Long
Some light is reflected
Low efficiency of photosynthesis in plants
Respiratory loss
Lost as heat
Efficiency of transfer to consumers is greater than efficiency of transfer to producers
Efficiency lower in older animals
Carnivores use more of their food than herbivores
Explain how the intensive rearing of domestic livestock increases net productivity. 5points
Slaughtered while young so energy transferred into biomass
Fed on controlled diets so higher proportion of food absorbed
Movement restricted so less energy lost
Kept inside so less heat loss
Genetically selected for high productivity
Describe the need for plants to both photosynthesise and respire. 6marks
No ATP production by photosynthesis in the dark
Not enough ATP energy generated in photosynthesis alone for the plant
Not all the plant photosynthesise
ATP can not be moved from cell to cell
ATP for active transport
ATP for synthesis
The concentrations of carbon dioxide in the air at different height above ground in a forest changes over a period of 24 hours, use your knowledge of photosynthesis to describe these changes and explain what they occur.

At night there are high conc of co2
No photosynthesis at night
So plants respire
Plants use more co2 than they produce
Less co2 concentration the higher you go
At ground level fewer leaves
Net primary production formula
NPP=GPP-R
