Our Changing Environment Midterm 1

An entity composed of diverse but inter-related parts that function as a complex whole. Example: atmospheric system
individual parts of a system. Example: temp and pressure
State of a system
a set of important attributes that characterize a system at a particular time. Example from biosphere: body temp, level of nutrition, blood pressure
couplings are the links between system components. Example: if you are cold, turn up heating blanket to make you warmer. Two kinds: positive and negative couplings.
positive coupling
a change in one component is a stimulus that leads to a change in the same direction in the linked component. Example: If there’s a trend of increasing temp, a positive coupling means the temp continues to increase.
negative coupling
a change in one component is a stimulus that leads to a change in the opposite direction in the linked component. Example: If there’s a trend of the temp increasing, a negative coupling means the temp starts to decrease
feedback loops
two couplings represent a “round trip” or feedback loop
a self-perpetuating mechanism of change and a response to that change
if a system is in equilibrium, it does not change unless the system is disturbed. Example: as long as the amount of incoming solar radiation equals the amount of outgoing solar radiation, the overall temp of the Earth-atmosphere system will not change
a system with a single negative feedback loop is in stable equilibrium
a system with a single positive feedback loop is in unstable equilibrium
a temporary disturbance of a system. Example: a volcanic eruption in Hawaii produces not only lava, ash, gas, and “bombs”, but also lightning and a waterspout
Example of explosive volcano erupting:
Sarychev, a Russian volcano on youtube video that was being filmed from the space station.
Example of eruption of Mt. Pinatubo, Luzon Island, Phillipines.
exploded June 14-15, 1991 (after inactive for 460 years) eruption was vertical, upwards. Put enough dust and aerosols to cool the Earth’s climate about 1 degree F for about a year. The eruption of Mt. Pinetubo “perturbed” the Earth’s climate for a very short amount of time.
a forcing causes a “permanent” change in climate. Example: app 225 MYA during the Permian geologic period, the Earth’s continents were together in 1 land mass called “Pangea”: -one large ocean called Panthalassa; -no Atlantic Ocean or Gulf of Mexico, therefore no source of humidity and this area was very dry- unlike today; -ocean currents and winds also must have been different
1) self-regulation of natural systems does not require that the system itself be intelligent. Example: Earth has supported life in some form for at least 3 billion years
2) after mass extinctions, life has always returned, but it was never the same as before