Feedback Loops

If the environment gets cold, we will often shiver in order to:

• keep body temperature the same as the external temperature
• decrease body temperature
• increase body temperature
• regulate blood pressure

What type of feedback loop is shown?

• negative
• neutral 
• positive

The two types of feedback systems that help organisms maintain homeostasis are:

• positive and negative 
• receptor and effector
• static and dynamic
• minor and major

As the Earth warms, increased evaporation produces more clouds. Clouds increase albedo, reflecting more light away from the Earth. The temperature falls. Rates of evaporation fall.

• Positive Feedback Loop

• Negative Feedback Loop

As the Earth warms, ice cover melts, exposing soil or water. Albedo decreases. More energy is absorbed by the Earth’s surface. Global temperature rises. More ice melts.

• Positive Feedback Loop

• Negative Feedback Loop

In a negative feedback loop, each action creates a consequence that _____________________ the other action.

• decreases

• has no effect on

• amplifies

Does the graph show positive or negative feedback?

• Positive, because when the red line shifts, the blue one does also

• Negative, because the blue line starts below equilibrium

• Negative, because the two actions are keeping each other near equilibrium

• Both positive and negative because the graph moves up and down

Loops that cause a response to build up and build up until something big happens are called ____________ loops

• positive

• negative

Body temperature regulation is an example of a ______________ loop

• positive

• negative

Negative Feedback Loops:

• amplify processes
• prevent small changes from getting larger
• are initiated during childbirth
• are found only in plants