Energy Transfers Flashcards
Define biomass
- mass of carbon
- dry mass of tissue per given area
Suggest what you should do to ensure all water is removed from a tissue/sample.
- regularly weigh and heat (less than 100’C)
- until mass is constant
Fresh mass is…
- living
- easy to assess
- variable water content
- unreliable
- variable food ingested
Dry mass is…
- dead
- difficult to assess
- small sample size
- unreliable
- situational
How to calculate energy stored in biomass…
- using calorimetry
- rly biomass combusted within sealed chamber
- chamber surrounded by water bath
- heat energy releases causes tem rise in water
- using SPHC of water, VOLUME of water and tEMP RISE, calculate energy released from mass of burnt biomass
Energy loss between trophic levels is…
- energy lost at each level in food chain
Percentage of energy trapped by produces is low, explain why.
- reflected/absorbed by water vapour
- reflected from produces
- wrong wavelength
- transmitted to few chloroplasts
What is GPP (gross primary production)?
- chemical energy stored in a plants biomass in a given area or volume
What is NPP (net primary production)
- chemicals energy stores in a plants biomass after respiratory losses to environment
NPP =
GPP - R (respiration)
N = I - (F - R)
- N = net production of consumers
- I = chemical energy store of ingested food
- F = energy lost in faeces and urine
- R = energy lost in respiration
Suggest two reasons why most of the light falling on producers is not used.
- light reflected
- wrong wavelength
- light misses chlorophyll
- CO2 concentration is limiting factor
Biomass of primary consumers is less than the biomass of producers. Explain why.
- loss of energy
- in respiration
- in excreta
- inedible parts
Explain how the intensive rearing of domestic livestock increases net productivity.
- restrictive movement so less respiratory loss
- keeping indoors so reduced heat loss
- feeding is nutritious
- food source easier to absorb so less lost in egestion
- selective breeding
Slaughtered before adulthood so more energy transferred to biomass
Describe the need for plants to both photosynthesis and respire.
- in the dark, no ATP production
- some tissues unable to photosynthesise
- ATP cannot be moved from cell to cell
- plant uses more ATP than produced in photosynthesis
- ATP for active transport
- ATP for synthesis
Percentage efficiency =
Energy available after transfer / energy available before transfer x 100
Producers to primary consumer…
- plants boost in faeces
- not all eaten e.g. roots
- some lost in excretion
- energy lost in respiration and to environment
