PCB 3044
PCB 3044 - Exam 4 (Final) 2026 Updated
Which systems would allocate more primary production to roots? why?
Systems with higher soil, water, and nutrient availability because of the
acquisition of the resources that are in short supply
Which systems would allocate more primary production to leaves and stems?
Why?
plants growing in dense communities with neighbors that may shade them may
allocate NPP in order to capture more sunlight for photosynthesis
Which successional stages usually have the highest levels of net primary
production?
Mid-successional stages
Which locations have the highest amounts of primary productions? Why?
Tropics (due to high availability of climate) and Coastal Areas (due to upwelling -
- absorption and reflection of light)
Which locations have the lowest amounts of primary productions? Why?
NPP decreases with the variation of climate when moving to the North or South
(due to latitudinal gradients in temp and precipitation)
How is primary production measured?
Measured by the amount of carbon in a system, produced by autotrophs
(photosynthesis and chemosynthesis)
Direct measures of primary production:
Net Ecosystem Exchange (NEE), which measures GPP and respiration to calculate
net exchange of CO2
Indirect measures of primary production:
Remote sensing through satellite scanning
Gross Primary Production:
PCB 3044
, PCB 3044
Amount of carbon fixed by autotrophic organisms in an ecosystem, controlled by
the rate of photosynthesis and leaf area index
Net Primary Production
Energy produced by autotrophs and stored as biomass (NPP = GPP - respiration)
Carbon Source
GPP < respiration
Carbon Sink
GPP > respiration
What systems have higher consumption rates of primary production? Why?
Producers (autotrophs) have the highest consumption rate because they
generate dead organisms, chemical energy, and plants
Raymond Lindeman's Study from lake ecosystem
- Grouped organisms together based on trophic levels
- Focused on energy base of system and efficiency of energy transfers
Bottom-up vs. Top-down control on production
Species decrease in top-down controls can influence availability of energy and
flow of energy between levels, recovery often occurs from bottom-up
In which ecosystem are biomass and energy pyramids the same
Terrestrial systems; plants are primary autotrophs and dominant source of
biomass in system
Which ecosystems have different shaped pyramids?
Aquatic systems (they are inverted); phytoplankton source of energy but small
proportion of biomass and has high turnover rates
Factors controlling number of trophic levels in an ecosystem
most ecosystems have 3-4 trophic levels
Number of levels varies in different ecosystems because of
- amount of NPP
-Addition/loss of species
PCB 3044
PCB 3044 - Exam 4 (Final) 2026 Updated
Which systems would allocate more primary production to roots? why?
Systems with higher soil, water, and nutrient availability because of the
acquisition of the resources that are in short supply
Which systems would allocate more primary production to leaves and stems?
Why?
plants growing in dense communities with neighbors that may shade them may
allocate NPP in order to capture more sunlight for photosynthesis
Which successional stages usually have the highest levels of net primary
production?
Mid-successional stages
Which locations have the highest amounts of primary productions? Why?
Tropics (due to high availability of climate) and Coastal Areas (due to upwelling -
- absorption and reflection of light)
Which locations have the lowest amounts of primary productions? Why?
NPP decreases with the variation of climate when moving to the North or South
(due to latitudinal gradients in temp and precipitation)
How is primary production measured?
Measured by the amount of carbon in a system, produced by autotrophs
(photosynthesis and chemosynthesis)
Direct measures of primary production:
Net Ecosystem Exchange (NEE), which measures GPP and respiration to calculate
net exchange of CO2
Indirect measures of primary production:
Remote sensing through satellite scanning
Gross Primary Production:
PCB 3044
, PCB 3044
Amount of carbon fixed by autotrophic organisms in an ecosystem, controlled by
the rate of photosynthesis and leaf area index
Net Primary Production
Energy produced by autotrophs and stored as biomass (NPP = GPP - respiration)
Carbon Source
GPP < respiration
Carbon Sink
GPP > respiration
What systems have higher consumption rates of primary production? Why?
Producers (autotrophs) have the highest consumption rate because they
generate dead organisms, chemical energy, and plants
Raymond Lindeman's Study from lake ecosystem
- Grouped organisms together based on trophic levels
- Focused on energy base of system and efficiency of energy transfers
Bottom-up vs. Top-down control on production
Species decrease in top-down controls can influence availability of energy and
flow of energy between levels, recovery often occurs from bottom-up
In which ecosystem are biomass and energy pyramids the same
Terrestrial systems; plants are primary autotrophs and dominant source of
biomass in system
Which ecosystems have different shaped pyramids?
Aquatic systems (they are inverted); phytoplankton source of energy but small
proportion of biomass and has high turnover rates
Factors controlling number of trophic levels in an ecosystem
most ecosystems have 3-4 trophic levels
Number of levels varies in different ecosystems because of
- amount of NPP
-Addition/loss of species
PCB 3044
