Ecological Feedback Loops

1.2 Systems in Environmental Science

Earths Interacting Systems

-A system is a collection of interdependent parts enclosed within a defined boundary
-Inputs into Earth’s interconnected systems include energy, information, and matter.

-Feedback loops regulate systems.There are 2 main types:

Negative feedback loops: Result in
stabilization
of a system
Ex. Predator vs Prey

Positive feedback loops:
Result in a
system moving
to an extreme
Ex. Erosion

Predator-prey cycles are negative feedback loops. If prey populations rise, predator populations can rise in response, causing prey populations to fall. Then predator populations may decline, allowing prey populations to rise again, and so on.

Negative feedback loop

Multiple Choice

A thermostat in a central heating system can determine the temperature of your living room. It switches the air conditioner on when the temperature increases to a predetermined level and shuts it off when it cools to another level. The room temperature remains within a comfortable level regardless of the temperature outside.

• Positive Feedback Loop

• Negative Feedback Loop

Multiple Choice

A ________________ feedback loop makes a system more stable.

• Positive

• Neutral

• Negative

• Circular

Multiple Choice

A _________________ feedback loop moves a system to an extreme.

• Positive

• Neutral

• Circular

• Negative

Multiple Choice

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

• decreases

• has no effect on

• amplifies

Multiple Choice

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

• decreases

• has no effect on

• amplifies

Multiple Choice

An avalanche had snow, debris and most of the mountainside sliding down the hill. What kind of feedback is shown in this example?

• Positive Feedback mechanism

• Hormone

• Homeostatic state

• Negative feedback mechanism

Multiple Choice

A wolf population is introduced into an ecosystem, causing the deer population to decrease. The wolf population decreases as the deer population decreases, allowing the deer to begin to increase again. This is an example of what type of feedback?

• Neutral

• Ecosystem

• Positive

• Negative

Multiple Choice

Is the graph showing positive or negative feedback?

• Positive

• Negative

Multiple Choice

The following is an example of what type of feedback loop?

• Negative Feedback Loop
• Neutral Feedback Loop
• Positive Feedback Loop
• Global Warming Feedback Loop

Multiple Choice

Which of the following would be considered a positive feedback loop?

• Body regulating its temperature

• Erosion

• Blood sugar regulation

• The AC in your house making the house colder when it gets too hot

Multiple Choice

Which of the following would be considered a negative feedback loop?

• Predator vs prey

• Erosion

• deforestation

Multiple Choice

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

Spheres of Function

•Earth can be divided into spheres that are defined
according to their location and function.

Lesson 3.2 Systems in Environmental Science

Multiple Choice

Which of Earth's spheres includes the inner and outer cores, and upper and lower mantles?

• Atmosphere

• Biosphere

• Geosphere

• Hydrosphere

The Geosphere

•Crust: Thin, cool, rocky outer “skin”

•Mantle: Very hot and mostly solid

•Core: Outer core is molten metal, inner core
is solid metal

Lesson 3.3 Earth’s Spheres

•Rocks and minerals on and below Earth’s surface:

•Biosphere: The part of Earth in which living and
nonliving things interact

•Atmosphere: Contains the gases that organisms
need, such as oxygen; keeps Earth warm enough
to support life

The Biosphere and Atmosphere

Lesson 3.3 Earth’s Spheres

The Hydrosphere

•Consists of Earth’s water

•Most of Earth’s water (97.5%) is salt water.

•Only 0.5% of Earth’s water is unfrozen fresh water
usable for drinking or irrigation.

•Earth’s available fresh water includes surface water
and ground water.

Lesson 3.3 Earth’s Spheres

Did You Know?If it is depleted, groundwater can
take hundreds or even thousands of years to
recharge completely.

Multiple Choice

Which of the following describes an interaction between the biosphere and geosphere?

• Rocks eroding due to wind
• Plants growing in soil
• Water evaporating from a lake
• Animals migrating to find food