1
8 and 12 billion
What was one effect of the exposure of tufa towers due to the lowering of Mono Lake's water level?
Easier prey access to for birds
How does a positive feedback loop differ from a negative feedback loop?
It continuously moves the system variable away from the stable point
How did the withdrawal of water by Los Angeles from Mono Lake tributaries impact the lake system?
Dropped lake level by 40 feet in 40 years
Over what period have global temperatures and atmospheric concentrations of carbon dioxide and methane fluctuated frequently?
Past 160,000 years
The first step in the scientific method is to ____
Observe the natural world
What type of system is the Earth with respect to matter?
Closed
What was the primary cause of decline in bird population in Mono Lake?
Over-predation of flies and shrimp
What is the primary human activity responsible for producing carbon dioxide?
Combustion of fossil fuels
In agriculture, what does the term intensity refer to?
Amount of food grown per unit of land
Historically, ecologists considered ecosystems that had exhibited no temporal trend between ecosystem inputs and outputs to be in _____
Steady State
What is the primary factor contributing to the increase in salt concentration in Mono Lake?
Continual input of salts from tributaries combined with evaporation
What does a negative feedback loop typically do to a system variable?
Brings it back to a starting point
In population dynamics, what happens when a population exceeds its carrying capacity?
The population crashes
What is the estimated "background" rate of mammal extinctions per 10,000 species per one hundred years?
2
Which human developmental stage is particularly sensitive to lead exposure?
In the context of system analysis, a flux represents _____
Change in the pool of resources
What type of feedback loop is described when a gambler continues to bet more money as they lose?
Positive Feedback loop
What is the definition of environment?
The conditions and factors surrounding an organism, including living and nonliving elements
What term describes the phenomenon where a population exceeds its carrying capacity, leading to a subsequent dramatic decline?
Overshoot
Since 1975, technological improvements have increased the fuel efficiency of most cars in the United States from an average of _____ miles per gallon to more than _____ miles per gallon by 2021.
Thirteen; thirty
What is the overshoot in the context of system dynamics?
Exceeding the stable set point of a system
Lead was historically used extensively, despite its toxic effects, because it....
is soft and malleable
What can a mean residence time be calculated?
When the system is in steady state
What is the significance of the human component in environmental systems?
It underscores how human activities intersect with and impact environmental systems.