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What is mean residence time(MRT)?
a)time required for a pollutant to accumulate in a reservoir
b)time taken for a system to reach a steady state
c) the average amount of time a quantity of a variable stays in a given pool
What is the average amount of time a quantity of a variable stays in a given pool?
Over what period have global temperatures and atmospheric concentrations of carbon dioxide and methane fluctuated frequently?
a) past 160,000 years
b) past 10,000 years
c)past 100 years
What is past 160,000 years?
In the case of Mono Lake, no water flows out into streams or rivers because__.
a)it is the lowest point in the landscape
b)it has a higher evaporation rate
c)it is a seasonal lake
What is it is the lowest point in the landscape?
What type of system is the Earth with respect to matter?
a)isolated
b)sealed
c)closed
What is closed?
Which of the following is NOT considered an important area for understanding environmental systems?
a)policy
b)law
c)Medicine
What is medicine?
What was one effect of the exposure of Tufa towers due to the lowering of Mono Lake's water level?
a)decrease in bird population
b)increased population of flies and shrimp
c)easier prey access for birds
What is easier prey access for birds?
What term do systems analysts use to describe the balance of a system?
a)input
b)pool
c)flux
What is pool?
A system is defined as being at a steady state when___.
a)input exceeds output
b)input equals output
c) The system is not utilized sustainably
What is input equals output?
How does a positive feedback loop differ from a negative feedback loop?
a)It does not affect the system variable
b)it maintains the system variable at a constant level
c)It continuously moves the system variable away form the stable point.
What is It continuously moves the system variable away form the stable point?
When can a mean residence time be calculated?
a)when the system is unaffected by external factors
b)when the system is losing material
c)when the system is in steady state
What is when the system is in a steady state?
What is the primary factor contributing to the increase in salt concentration in Mono Lake?
a)decrease in evaporation
b)absence of sodium in tributaries
c)continual input of salts from tributaries combines with evaporation
What is the continual input of salts from tributaries combined with evaporation?
a)underscores how human activities intersect with and impact environmental systems
b)proves that human societal structures have no role in environmental
c)indicates that humans are unaffected by environmental changes
What is underscores how human activities intersect with and impact environmental systems?
What does a negative feedback loop typically do to a system variable?
a)Brings it back to a starting point.
b)Increases the variability of the variable
c)Maintains it at a constant level
What is increases the variability of the variable?
What is the primary energy source for the photosynthetic algae in Mono Lake's ecological system ?
a)brine shrimp
b)gulls
c)sun's light
What is the sun's light?
Approximately how many known species are there on Earth today?
a)1 billion
b)1.8 million
c)100,000
What is 1.8 million?
According to the Science Resource Guide, which of the following can the loss of keystone species lead to?
a)decrease in biodiversity
b)stability in ecosystems
c)increase in biodiversity
What is a decrease in biodiversity?
What is the definition of environment?
a)area immediately surrounding an organism or person
b)weather patterns in a specific region
c)conditions and factors surrounding an organism, including living and nonliving elements
What is conditions and factors surrounding an organism, including living and nonliving elements?
What methodology is environmental science primarily based on?
a)engineering principles
b)economic analysis
c)the scientific method
What is the scientific method?
What was the primary cause of Mono Lake's bird population decline?
a)accelerated growth of algae population
b)over-predation of flies and shrimp
c)increase in alkaline dust storms
What is over-predation of flies and shrimp?
In the context of system analysis, a flux represents___.
a)rate of flow
b)balance
c)change in the pool of resources
What is change in the pool of resources?
What is the estimated "background" rate of mammal extinctions per 10,000 species per one hundred years?
a)2
b)0.2
c)10
The maximum number of individuals that an environment can support is known as its__.
a)limitation capacity
b)carrying capacity
c)decay capacity
What is carrying capacity?
Which type of system allows for the exchange of both matter and energy with other systems?
a)isolated
b)open
c)sealed
What is open?
Historically, ecologists considered ecosystems that had exhibited no temporal trend between ecosystem inputs and outputs to be in___.
a)symbiosis
b)steady state
c)disarray
What is steady state?
a)negative feedback loop
b)balanced feedback loop
c)positive feedback loop
What is positive feedback loop?