Bell Ringer What types of community interactions among organisms help shape ecosystems?

What shapes an ecosystem? 4.2

The Niche Food organism eats Physical conditions needed for survival When & where it reproduces No two species can share the same niche in the same habitat but different species can have similar niches

Competitive exclusion principle- no two species can occupy the same niche/same place/same time

Barnacles

Community interactions 1. Competition 2. Predation 3. Symbiosis Mutualism Commensalism Parasitism

Community interactions Competition when organisms compete for the same resources Competition activity Need two volunteers Colored marshmallows

Community Interactions 2. Predation one organism captures & feeds on another

Community interactions 3. Symbiosis---two different species live together Mutualism- both species benefit Commensalism- one benefits without harming the other Parasitism- one lives on another while causing harm

mutualism

commensalism

Parasitism

Ecological Succession Ecosystems are constantly changing in response to natural & human disturbances 2 types: Primary occurs on surfaces where no soil exists (volcanic activity) Secondary ecosystem restores to original condition after disturbance is over (fires, farming, etc.)

Primary succession

Secondary succession

The new island of Anak Krakatau http://videos.howstuffworks.com/hsw/8276- islands-and-evolution-the-new-island-of- anak-krakatau-video.htm http://videos.howstuffworks.com/discovery/2 9496-assignment-discovery-succession-in- the-environment-video.htm

Any questions???