C4.2 Transfer of energy and matter Flashcards
System
Set of interacting or independent components
Open system
Resouces (matter and energy) can enter and exit
Close system
Energy can enter and exit but not matter
Ecosystem
All organisms interact an area with the non living environment
Factors affecting light availability in marine and freshwater ecosystems
Shorter wavelengths penetrate further
Living and non living matter in water reduce light penetration
Coastal waters are often cloudy due to sediments/phytoplankton
Little to no light beyond 200m in open ocean
Food chain
Sequence of organisms, each feeding on the previous
Features of food chains
First organism is a producer
Tropic levels are numbered from 1
Consumer that feeds on producer is primary consumer, and so on
Top consumer is apex predator
Arrows indicate direction of energy flow
Food web
Diagram that summarises all known food chains in a community
Photoautotroph
Organisms that use light energy as external energy source needed to make organic molecules
Chemoautotroph
Organisms that use exothermic chemical reactions as external energy source
Assimilation
Use of organic molecules to synthesize new compounds needed by cells
Cells use ATP energy for
Synthesizing large molecules
Moving molecules across membranes
Moving structures within cells
Maintaining body temperature
Energy pyramid units
kJm^-2yr^-1
Incomplete consumption
When an organism is not fully consumed
Cell respiration
Organic molecules are oxidised to molecules of H2O and CO2
Incomplete digestion
When some parts of animals/plants are not fully digested/absorbed and leaves as faeces
Production in ecosystems
Accumulation of carbon compounds in biomass
Productivity
Rate at which biomass is created
Gross primary production
Total biomass of carbon compounds made in plants by photosynthesis
Net primary production
GPP minus biomass lost due to respiration by plant cells
Units of NPP
gm^-2yr^-1
Primary production
Accumulation of carbon compounds in biomass by plants/autotrophs
Secondary production
Accumulation of carbon compounds by animals and other heterotrophs
Pool
Reserve of an element
Flux
Transfer of the element from one pool to another
3 main types of carbon flux
Photosynthesis, feeding, respiration
Carbon sink
When photosynthesis exceeds respiration, net uptake
Carbon source
When respiration exceeds photosynthesis, net release
Combustion reaction
Hydrocarbon (s/l/g) + Oxygen (g) -> Carbon dioxide (g) + Water (g)
Keeling curve
Graph plotted from analysis results of atmospheric CO2 concentrations
Annual fluctuations
Rises in October - May, falls May - October due to seasonal fluctuations to carbon fixation by photosynthesis and release by respiration
Long term trend
Net increase in atmospheric CO2 concentration after annual fluctuations accounted for
Carbon flux units
GtCyear^-1
Chemical elements needed by living organisms
C, H, O - makes carbohydrates, lipids and carbon compounds
N, P - additional requirements for DNA and nucleic acid synthesis
