Chapter 18 Primary and Secondary Production Flashcards
Which ingredient is not required in the process of carbon fixation to occur?
O2
Which of the following is not one of the uses of forest biomass?
It is used as an energy source for photosynthesis.
When studying ecosystems, Arthur Tansley realized the importance of considering organisms and their environment as a(n) ______ system.
integrated
Which ecosystem components are studied by an ecosystem ecologist?
flow of nutrients
flow of water
flow of energy
Which statement best fits the definition of primary production over some period of time?
production of new organic matter by autotrophs
Select the statement that best describes the process of carbon fixation.
PAR converts CO2 into sugar and other biomass.
Which formula best represents the rate of primary production?
1,000 m3 new biomass / week
Primary production is the rate (area or volume divided by time) at which primary production is occurring
Which organism would directly use the biomass produced by forest vegetation?
rabbit
The type of production that is a measure of the total amount of biomass produced by all of the autotrophs is ______.
gross primary
An ecosystem is a biological community and all of the ______.
abiotic factors influencing it
Identify the different ways in which primary production is measured.
the levels of oxygen production by primary producers
the rate of carbon uptake by primary producers
the amount of biomass produced by producer
Which statement is true in regard to studying ecosystems according to Tansley?
The chemical, physical, and biological process are equally important to study.
When determining an organism’s trophic level, what group is used as the start of the transfer of energy?
primary producers
The general class of organisms that are responsible for primary production is _____
autotrophs
In which trophic level are the carnivores that feed upon herbivores placed?
third
How is the rate of primary production measured?
Amount of biomass / interval of time
Which environmental conditions would most likely produce the highest primary productivity?
warm and moist
Which type of primary production will have a larger value?
gross
What is annual actual evapotranspiration (AET)?
the total amount of water that evaporates and transpires during the course of a year
What is one of the main ways in which primary production is measured?
the rate of carbon uptake by primary producers
What is the definition of a trophic level?
an organism’s position within a food web
Which two ecosystems would have the lowest AET levels?
tundra
hot desert
In what trophic level are detritivores placed?
second
Identify the two key variables that are highly correlated with variation in terrestrial primary production.
moisture
temperature
From the choices given, identify the biome that has the greatest net primary productivity.
temperate deciduous forest
Annual actual evapotranspiration (AET) is reported in what way?
millimeters of water evaporated and transpired per year
Which two states had the highest net primary productivity in the central grassland region of the United States?
Arkansas
Mississippi
Which variable helps explain the difference in terrestrial primary productivity within the same ecosystem?
soil fertility
Which ecosystem would you predict would have the highest AET?
jungle
Liebig’s Law of the Minimum helped scientists gain which perspective about primary productivity?
Variation in soil fertility can affect the rates of primary production.
Which nutrients were included in the fertilizer added to the Alaskan tundra during the Shaver and Chapin study?
nitrogen
potassium
phosphorus
Identify the biome that has an actual evapotranspiration rate closest to 250 mm H2O / yr.
Arctic tundra
Identify the minimum increase in net primary production at the Shaver and Chapin Alaska tundra study sites.
23%
Which statement is correct about the levels of net primary productivity in the central grassland region of the United States?
Primary production was highest in the east and lowest in the west.
Primary production increased by 178% when nitrogen and phosphate were added to a dry alpine meadow. How much did the primary production increase when only nitrogen was added?
63%
Which two soil nutrients play the greatest role in determining terrestrial primary productivity?
phosphorus
nitrogen
Which nutrient was found to be a limiting nutrient in the wet meadow but not in dry meadow?
phosphorus
Which statement describes Liebig’s (1840) Law of the Minimum?
A single nutrient controls primary productivity.
Which nutrient was determined to be a limiting factor in the biomass of phytoplankton?
total phosphorus
What was the source of the nutrients Shaver and Chapin added to the arctic tundra during their study?
commercial fertilizer
Which nutrient proved to be a limiting factor in the phytoplankton biomass in temperate zone lakes?
phosphorus
Identify the maximum increase in net primary productivity at the Shaver and Chapin study sites.
300%
Which nutrients produce an increase in phytoplankton biomass in the Experimental Lake Area study area?
carbon
sucrose
nitrate
Which combination of fertilizers produced a 178% increase in primary production of the dry alpine meadow?
nitrogen and phosphorus
How did Lake 226 respond once the fertilizer was no longer being added?
The phytoplankton biomass declined.
Which nutrient is considered the main nutrient that limits net primary production in dry meadows?
nitrogen
Which region of the ocean will have the highest net primary productivity?
Over continental shelves
What is the correct relationship between total phosphorus and plankton biomass when conditions are otherwise good for plankton growth?
High total phosphorus is correlated with high phytoplankton biomass.
The term used for the movement of water that brings nutrients to surface waters the ocean from deeper waters is ______
upwelling
What would likely occur to the phytoplankton biomass of a lake if a large amount of phosphorus were to be added?
The biomass would increase.
What feature prevents the open ocean from experiencing a significant amount of vertical mixing?
A permanent thermocline
Which nutrient combination increased the phytoplankton biomass the most in the Experimental Lake Area study?
carbon, nitrate, and phosphate
How did Lake 226 respond to the addition of nutrients?
The phytoplankton biomass increased.
The nutrient that is most often the limiting factor for marine ecosystems is _____
nitrogen
Which regions of the ocean have the highest net primary productivity? (Select all that apply.)
Areas over continental shelves
Areas of upwelling
Margins of the continents
Which residual variation factor, suggested by Dillon and Rigler, is believed to influence phytoplankton biomass?
Intensity of predation on the zooplankton.
In what ways are nutrients renewed along continental margins? (Select all that apply.)
breakdown of organic matter
upwelling of the ocean currents
runoff from land
What is the main source of nutrient renewal in the open ocean?
Vertical mixing
A collection of plants with similar physiological and anatomical characteristics that influence their seasonality, resources requirements, and life histories is known as a(n) ______.
plant functional group
In which aquatic ecosystem is nitrogen the limiting nutrient for phytoplankton biomass?
marine
What is the scatter of points around lines showing a relationship between nutrient concentrations and phytoplankton biomass called?
Residual variation
As the number of algal species increases in a lake, you would expect ______ in primary production
an increase
A plant functional group consists of plants with similar ______ that influence their seasonality, resource requirements, and life histories.
physiological and anatomical characteristics
Identify the bottom-up control.
average temperature
Identify the top-down control.
Which nutrient combination increased the phytoplankton biomass the most in the Experimental Lake Area study?
The nutrient that is most often the limiting factor for marine ecosystems is ______
nitrogen
Which organism would most likely cause a trophic cascade?
grey wolf
Which of the following is the first step in a trophic cascade in a freshwater lake?
Piscivore fish feed on the planktivorous fish.
The primary production of a large lake has been increasing over time; a likely cause is ______ the lake.
an increase in the diversity of primary producers in
Organize the order of events, with the first at the top, that occurred when the levels of planktivorous fish was reduced in a lake.
- predaceous invertebrate pop inc
- herbivorous pop shifted to larger individ
- herbivorous pop fed upon phytoplankon
- phytoplankon biomass and rate of primary prod declined
Which of the following factors are bottom-up controls of ecosystems?
physical factors
chemical factors
Organize in order, with the first change at the top, the events that would occur in a lake ecosystem if the biomass of planktivorous fish increased.
- zooplankton biomass dec
- avg size of herbivorous zooplank dec
- phytoplank biomass inc
- primary prod inc
Which of the following is a type of top-down control on ecosystems?
type of predators
The group of herbivorous organisms responsible for consuming 66% of the primary production on the Serengeti grasslands is _____
grazers
What are the effects of a trophic cascade?
a change in the prey abundance
a change in the productivity of a population
a change in the biomass
Which abiotic factors stimulate plant production in a grassland ecosystem?
rainfall levels
soil fertility
List in order, with the highest consumer at the top, the steps of a trophic cascade in a freshwater lake.
- pisciover fish feed on plankon fish
- plankton fish feed on zooplank
- zooplank feed on phyto
- phyto determeine biomass lvl
What happened when the levels of planktivorous fish were reduced in a lake?
There was a decrease in primary productivity.
What mechanisms underly compensatory growth?
lower rates of respiration
a reduction in self-shading
Identify the correct result of an increase in the biomass of planktivorous fish in a lake ecosystem.
The zooplankton biomass decreased.
Which type of grazing pattern resulted in compensatory growth of the plants?
intermediate intensity
What type of potential influence do grazers have on the primary production of the Serengeti grasslands?
high
What was the primary production when the grazing intensity reached 0.4?
450 g/m2/yr
Which influences on grassland ecosystems are produced by grazing mammals?
soil fertility
plant production
What happens to sunlight as it shines upon a forest?
Some is reflected from the forest canopy.
Some is converted into heat energy.
Trophic dynamics is the transfer of energy from one part of an ecosystem to ______.
another part of it
What event would cause plants to undergo compensatory growth?
grazing by herbivores
During ecological transfer, about 5% to __% of the energy is transferred from a lower trophic level to a higher one.
20%
Why does heavy grazing not result in compensatory growth of plants?
It reduces the plant’s capacity to recover.
True or false: There is no theoretical upper limit on the number of trophic levels that can exist in an ecosystem.
False
Which grazing intensity produced the highest primary production?
0.5
What plant structure is responsible for absorbing solar energy?
chlorophyll in the leaves
In what ways is energy lost in ecosystems?
loss of energy as heat
respiration by consumers
limited consumption
When studying trophic dynamics, what is the key component that is being discussed?
transfer of energy
Which of the following statements is true regarding the models displayed in the figure? Experimental and observational studies indicate ______.
greater support for the ratio-dependent model
The typical range of energy being transferred to the next higher tropic level varies from 5% to 20%. The percent transferred is called the ecological _____
Efficiency
What is the main source of energy at the bottom trophic level of the salt marsh ecosystem?
detritus of salt marsh grass
What is the factor in all ecosystems that limits the number of trophic levels present?
the amount of energy lost as the energy is transferred between trophic levels
What information did Peterson gain during his salt marsh study by investigating the ratios of stable isotopes?
the contribution of alternative food sources to the diet of the mussel
Out of the producers in the salt marsh study, plankton had the highest concentration of which isotope?
34 S
What happens to energy as it is transfered from one trophic level to the next?
Some energy is lost.
As primary production increases, the abundance of organisms ______.
increases at all trophic levels
What are the various forms of energy for consumers in a salt marsh?
phytoplankton
upland plants
detritus
Which isotopes did Peterson use in order to determine the food sources of mussels in the salt marsh?
sulfur
nitrogen
carbon
During the salt marsh study, which group of producers was the most depleted of 13 C?
Upland plants
