Aquatic Invertebrates (Biology)
River Continuum Concept
Understand the properties of a natural system
Break down a river system into its primary components
Discuss the importance of feedback loops and dynamic equilibrium
To develop the concept of systems as a way to analyze and understand the
form, function, and interconnectedness of nature.
To examine a river as a system balanced by interactions among its main
White boards and dry-erase markers
Our planet consists of many complex, large-scale, interacting systems.
is a network of
among a group of parts, elements, or components that
with and influence one another through the
exchange of energy
A system receives
(energy, matter, info),
or interact with
this input and responds with an
This exchange drives a
, or circular
process whereby a system’s output serves as input to that same system.
in a system interact with each other within feedback loops.
negative feedback loop
, the output acts as an input that moves the system in
This compensation stabilizes
For example, when your
brain processes an input that you are too warm, its output is too get cooler by removing a
jacket or turning on the air conditioner.
As you get cooler, you brain processes this new
input and outputs a response to turn off the air conditioner.
As a result of this opposite
input vs. output, or negative feedback loop, your body system stays at a stable
This alternating give-and-take cycle, or
keep a system within a healthy range.
Processes in the system move in opposite
directions at equivalent rates so their effects balance out.
The progression of dynamic
equilibrium acts to stabilize a system when it is disturbed by external forces.
positive feedback loop
, the output acts as an input that moves the system
further in the same
direction as the initial input.
This magnification of effects
For example, a desert environment can act as a system.
system’s components in this case are the living organisms.
If there are no predators in
this desert, such as coyotes and mountain lions, then jackrabbits can reproduce and there