Topic 5B - Energy Transfer And Nutrient Cycles Flashcards
How do plants use the sugars from photosynthesis
As respiratory substitutes
To synthesise other biological molecules
What is biomass
Total dry mass of tissue or mass of carbon measured over a given time in a specific area
How can the chemical energy store in dry biomass be estimated
Using calorimetery
What is Gross Primary Production
Total chemical energy in a plant biomass within a given volume or area
What is Net Primary Productivity
Total chemical energy available for plant growth, reproduction and energy transfer to other trophic levels after respiratory losses
How can the net production of consumers be calculated
N = I - (F + R)
What do the letters N, I, F and R stand for
N - net production
I - chemical energy from ingested food
F - energy lost as faeces or urine
R - respiratory losses
Why does biomass decrease along the food chain
Energy lost in urine or faeces
Energy lost as heat to the surroundings
Some of the animal can’t be consumed
Respiratory losses
Outline some common farming practices used to increase the efficiency of energy transfer
Exclusion of predators - no energy lost to other organisms in the food web
Artificial heating - reduce energy lost to maintain constant body temperature
Restriction of movement
Feeding is controlled at the optimum
Why is the length of food chains limited
Energy is lost at each trophic level
So there is insufficient energy to support a higher trophic level
Name the general stages in the phosphoprous cycle
- Weathering
- Runoff
- Assimilation
- Decomposition
- Uplift
Why is the phosphorous cycle a slow process
Phosphorous has no gas phase, so there is no atmospheric cycle
Most phosphorous is stored as PO43- in rocks
What happens during weathering and runoff
Phosphate compounds from rocks leach into surface water and soil
Why is phosphorous important to living organisms
Plants convert inorganic phosphate into biological molecules e.g. DNA, ATP, NADP
Phosphorous is passed to consumers via feeding
What happens during uplift
Sedimentary layers from oceans are brought up to land over many years
