Topic 5B: Energy Transfer and Efficiency Flashcards
Where do plants get energy from?
The sun
Energy + CO2 =
Glucose
What is glucose used for?
- respiration
- biomass
- synthesis of biological molecules
What is biomass?
Chemical energy stored in plants
Why is energy sometimes lost when light energy is converted to chemical energy?
- wrong wavelength
- light miss the chlorophyll
What are producers?
Organisms that make their own food (usually through photosynthesis)
Why do we use dry mass over fresh mass?
Because in fresh mass water varies so it makes it unreliable
How do you get dry mass from fresh mass?
- place mass in an oven at low temp
- water will evaporate
- measure mass at regular intervals until mass becomes constant.
Biomass can be measured using…
- dry mass
- using calOrimeter
How can you estimate the chemical energy in biomass?
- burn mass in calorimeter
- the amount of heat given off tells you how much energy is in it
- calculate the change in temperature
What is energy measured in?
KJ/J
Define GPP
Gross Primary Production
What is GPP?
The overall chemical energy that is converted from light energy in plants which they gain from photosynthesis
Define RL?
Respiratory Loss
What is respiratory loss?
Most of the GPP is lost through heat to the environment and this is because plants respire.
Define NPP
Net Primary Production
What is NPP?
The energy that is used for growth and respiration
How much energy is lost to the environment?
around 90%
How is energy lost?
- movement
- respire
- faces and waste
How do you calculate NPP
GPP - RL
What is the typical unit for rate of primary production?
- kj ha^-1 year^-1
- kj m^-2 year^-1
Net product in consumers =
I -(R+F)
What are the two ways energy is lost?
- The energy lost to other organisms eg pests
- The energy lost through respiration
How do farmers reduce energy loss through pests?
By using Chemical and Biological reagents
