Lecture 18 Flashcards
Primary productivity
“rate at which energy is captured and concerted into organic compounds by photosynthesis or chemosynthesis”
What are the organisms responsible for primary production?
Primary producers or autotrophs
Extremophiles
Organisms that are able to live in extreme conditions
Productivity
“rate at which energy is converted into organic matter”
Production
“biomass produced by organisms in an ecosystem over a given period of time”
Standing crop
“biomass of producers present in an area at a particular moment in time”
Units for productivity
kg C/m^2/year
Units for production
kg C/m^2
Units for standing crop
kg C/m^2
OR
kg C
Gross primary productivity (GPP)
“rate at which energy is captured and assimilated by producers in a given area”
Net primary productivity (NPP)
“rate at which energy is assimilated by producers and converted into biomass in a given area”
Equation for NPP
NPP = GPP - respiration
What factors change net primary production among ecosystems?
- Latitude
- Region
- Ecosystem type
Food chain
linear sequence of energy flow between organisms
- each group is the source of energy/nutrients for the next
Trophic level
“position in food chain that represents a group of organisms sharing the same primary source of nutrition and energy”
Secondary production
“rate of consumer biomass accumulation in an area”
Ecological efficiency
“the percentage of net primary production from one trophic level compared to the next trophic level”
Trophic pyramid
“a chart composed of stacked rectangles representing the amount of energy or biomass in each trophic group”
Equation for ecological efficiency
Net production at trophic level / Net production at next lower trophic level
Consumption efficiency
“percentage of energy or biomass a in trophic level that is consumed by the next higher trophic level”
Assimilation efficiency
“percentage of consumed energy that is assimilated”
Top-heaviness
“relatively high concentration of biomass or numbers at higher trophic levels compared to lower trophic levels”
