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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
1. 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/8276islands-and-evolution-the-new-island-ofanak-krakatau-video.htm
http://videos.howstuffworks.com/discovery/2
9496-assignment-discovery-succession-inthe-environment-video.htm
Any questions???