Download Community Ecology

Community Ecology
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A community is
• Multiple populations (different species)
• Share same general area/space
• Interacting
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Differ in their species richness
• number of species
• abundance of different species.
Ecological Niche
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Every population has a specific role (unique)
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Niche
• What it does
• How it does it
• Utilization of necessary resources
• Abiotic & biotic
Competition for resources
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Limiting factors
• 2 different species cannot share same need for
• 1 will out compete. Why?
• competitive exclusion principle
• Each species will have unique niche
» Resource partitioning
Community Interactions: competition, predation, mutualism and commensalism
Predation +/-
• Predator eats prey
• Herbivores eat plants
• Omnivores eat both
• Parasitism
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Parasite depends on a host
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Lice
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Tapeworms
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Harmful bacteria
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Athletes foot
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Mistletoe
• Will a successful parasite kill their host quickly or slowly?
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Mutualism +/+
• Aicatia tree & ants
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Commensalism +/0
• Barnacles attached to a whale.
Trophic structure
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The feeding relationships
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Transfer of food energy
• food chain
• Typically 4-5 links
• Source
• Producer
• Consumers (1-3)
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Part of niche
• Food webs.
• What transforms food chains into food webs?
• More realistic trophic structure
• Any species may be at more than one trophic level.
• Birds
Dominant species and keystone species
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Dominant species
• highest number or biomass
• Producers
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Keystone species
• Regulator
• Stabilize community
• Typically a predator
• keystone species removal
• Alters community structure
• What affect would this have on the rest of the community?