Energy transfers- Energy and Ecosystems Flashcards
What is a community?
All organisms living in a particular environment.
What do biotic and abiotic factors influence?
The distribution and abundance of organisms in a habitat.
What is a niche?
The role of a species in a habitat.
What are autotrophs?
Photosynthetic organisms that use the sun to produce their own food.
What are heterotrophs?
Organisms that cannot produce their own food.
How is energy lost to the surroundings in a food chain?
- Uneaten parts e.g. bones
- Decay of dead material
- Excretion
- Exothermic reactions e.g
respiration
What is the formula for the percentage efficiency of energy transfer?
Percentage efficiency =
Energy available befor transfer/energy available after transfer
× 100
How is biomass measured?
As mass of carbon or dry mass of tissue per given area per given time.
How is the energy stored in dry biomass measured?
A bomb calorimeter is used to burn a sample of a known mass in pure oxygen. The bomb calorimeter is submerged in water so the temperature change of the water can be used to estimate the energy in the sample.
What is the Net Primary Productivity (NPP)?
The chemical energy stored in plant biomass after respiratory losses have been taken into account.
What is the Gross Primary Productivity ( GPP) ?
The chemical energy store in plant biomass in a given area or voljme, in a given time.
What is the equation for NPP?
NPP = GPP - R
What is the equation for the net production of consumers (N)?
N = I - (F+R)
I= chemical energy in ingested food.
F= chemical energy lost in faeces and urine.
R= respiratory losses to the environment.
