Energy and ecosystem Flashcards
Define ecosystem
Formed form a community and the non living components of its enviroment
How do you measure dry mass
- Sample of organism is dried in an oven
- The sample is weighted after a certain amount of time
- The sample is dried again in the oven and re-weigh over and over until the mass remains constant which means all the water has been removed
What are the two until for dry mass
- Kgm-2yr-1
- Kgha-1yr1
Describe a methods using a calorimetry
- This is used to measure the chemical energy stored in organic material
- Dry mass burnt in oxygen in a combustion chamber
- Energy given off is used to heat a known volume of water
- Increase in temperature of water indicates energy contained in material
- The units are Joules / Kilojoules
Define gross primary production
Is the chemical energy store in plant biomass from photosynthesis, in an given area
Define net primary production
Is the chemical energy stored in plant biomass after respiratory losses have been subtracted
What is the formula to calculate NPP
NPP = GPP - R
Explain why the majority of the light that falls on the producer is NOT used in photosynthesis
. Light is reflected
. Light is the wrong wavelength
. Light misses the chlorophyll
. Carbon dioxide concentration and/or temperature is the limiting factor
What is the equation of energy transfer
Net production of trophic level÷ net production of previous trophic level ×100
Describe reasons for the low efficiency of energy transfer from producer to primary consumers
- The primary consumer do not eat all the grass( like the roots)
- They do not digest all the grass consumed( produce lots of feaces)
- Most of the energy they do absorb is used in respiration
- A lot of energy is used to keep themselves warm by moving around
How does adding fertilisers to soil improve productivity
Nitrates for protein synthesis, phosphate for ATP and DNA synthasis
How does weed killers, herbicides, pesticides improve productivity
To eleimate organisms that are part of a food Web which competes with the plant or animal that is being farmed
Hie does ploughing improve productivity
Allows nitrification and it improves draining
How does crop rotation improve productivity
To improve the soils nutrients
How does slaughtering livestock when they are still growing improve productivity
More energy is transferred into biomass
How does feeding livestock on a controlled diet improve productivity
A higher proportion of food is digested, absorbed and used for biomasd
