5.3 - Energy and ecosystems Flashcards
Define biotic and give examples
living
e.g predation, disease
Define abiotic and give examples
non-living
e.g light intensity, temperature, pH, moisture, humidity
Define autotroph
organisms that use energy from Sun to produce their own food
Define heterotroph
organism that cannot synthesise their own food
How much energy is passed on between organisms in the food chain?
10% (chemical food energy)
How is 90% of energy lost?
- uneaten parts e.g bones
- decay of dead material (by bacteria)
- excretion
- exothermic reactions e.g heat lost via respiration
State the % energy efficiency formula
energy available after transfer/energy available before transfer x 100
How can biomass be measured and how can chemical energy store in dry biomass be estimated?
mass of carbon or dry mass of tissue per given area
- using calorimetry
Define net primary productivity (NPP)
chemical energy store in plant biomass after respiratory losses to the environment
Define gross primary productivity (GPP)
chemical energy store in plant biomass in a given area/volume
State the equation that links net and gross primary production and respiratory losses
NPP = GPP - R
State the equation for net production of consumers (N)
N = I - (F+R)
I = chemical energy in ingested food
F= chemical energy lost to environment via faeces and urine
R = respiratory losses
Suggest how Arbuscular mycorrhiza fungi (AMF) may benefit from association with plants
provided with amino acids
How do plants synthesise organic compounds in an ecosystem?
from atmospheric, or aquatic CO2
What is primary and secondary productivity and how is it measured?
rate of primary or secondary production
- measured as biomass in a given area in a given time
e. g kJ ha–1 year–1
