How Ecosystems Work Part II

Nutrient Cycling & Change in Ecosystems

Carbon Cycle

• The process by which carbon is cycled between the atmosphere, land water, and organisms.

• Plants convert atmospheric CO2 into carbohydrates during photosynthesis and release CO2 during cellular respiration.– Ex: Elodea

http://mn-media-cluster-1.discoveryeducation.com/videos/1/Zeus_Animations/Carbon-Cycle_07-28_Fixed.swf

CARBON CYCLE

Nitrogen Cycle

• A process in which nitrogen is cycled between the atmosphere, bacteria, and other organisms.– Nitrogen-fixing bacteria are bacteria that live in plant

roots and convert atmospheric nitrogen into ammonia.

http://mn-media-cluster-1.discoveryeducation.com/videos/1/Zeus_Animations/Nitrogen-Cycle_07-28_Fixed.swf

Nitrogen Cycle

Phosphorus Cycle

• The movement of phosphorus from the environment to organisms and then back to the environment.

• (P) rock deposits land living organisms ocean

• Rarely occurs because phosphorus as a gas rarely occurs as a gas.

Phosphorus Cycle

Ecological Succession

• Ecological Succession– A gradual process of change and replacement of the types of species in a

community.

• Primary Succession– Occurs on a surface where no ecosystem existed before.

• Secondary Succession– Occurs on a surface where an ecosystem has previously existed.– Ex: Volcanoes – Pioneer Species - colonizes an uninhabited area and that starts an ecological cycle.

• Climax Community– The final, stable community in equilibrium with the environment.

What Type of Succession?

1st Year 2nd Year 3rd Year

What Type of Succession?

Climax Community