Section 5:Energy and ecosystems Flashcards
How does energy enter an ecosystem?
The sun gives out solar energy which is converted into organic matter via photosynthesis
Three points
Why is not all solar energy given out converted into organic matter?
- Reflected by clouds and dust/or is absorbed by the atmosphere
- Not the correct wavelength for photosynthesis
- Light does not hit the chlorophyll molecules
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What are producers?
Photosynthetic organisms which use energy from the sun to make organic substances
What are consumers?
Organism which obtain their energy by feeding on other organisms
What are saprobionts?
Decomposers which breakdown complex materials in dead organisms into simple ones
What is a food chain?
A feeding relationship
What is a trophic level?
A stage in a food chain
What are food webs?
Many food chains linked together
What is biomass?
The total mass of living material in a specifc area at a given time
Is dry or wet biomass more accurate?
Dry biomass
Why is wet biomass more accurate?
The water content of organisms varies
How do you caluclate the biomass of an organism?
Bomb calorimetry~dry biomass is weighed then burnt in pure oxygen within a sealed chamber,called a bomb
Four points
Why do organisms need energy?
- Movement~within an organisms(circulation of blood) and of an organism
- Active transport
- Production of substances
- Maintenance of core body temperature
What is gross primary production (GPP)?
The total quantity ofnenergy that plants convert into organic matter
What is net primary production?
What goes into biomass/rate at which they store energy
What are the units for NPP?
kJ m-2 year-1
Three points
Why is not all energy transfered between trophic levels?
- Not all of the of the organism is consumed
- Some energy losses occur as heat from respiration and directly from the body to the environment
- Some parts are consumed but can not be digested, so lost in feaces
What does N=I-(F+R) mean?
net production of consumers=chemical energy in ingested food-(energy lost through feaces, urine and undigsted food + food lost through respiration)
Why is energy lost from producers to primary consumers?
- Not all available food is eaten
- Energy is lost to use in respiration,heat and movement
Why is energy lost from primary consumers to secondary consumers?
Most of the herbivore can’t be eaten
How are phosphate ions oceans,lakes and soil trnasfered to plants?
Absorption from plants
How are phosphate ions in plants transfered to animals?
Feeding and digestion
What is mycorrhiza?
The associations between fungi and plant tooys
* Increase SA for water and mineral ion absorption
* Acts like a sponge for roots enabling plants to be drought resistant
