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Community Ecology
Intraspecific Interspecific
Types of Ecological Interactions (see also Table at end of Chapter)
species 1 species 2 (host) Competition -/+ -
Competitive Exclusion Principle
Lotka & Volterra
Gause, 1934
Paramecium spp.
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fundamental niche
vs.
realized niche fundamental niche
Resource partitioning
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Character displacement
Types of Ecological Interactions
species 1 species 2 (host) Competition -/+ - Predation + - Herbivory Parasitism Disease
predators
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Prey defense: behavioral
eg: musk oxen
Prey defenses: morphological
cryptic coloration/patterning
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countershading
Aposematic/warning coloration
Batesian mimicry
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Mullerian mimicry
monarch viceroy
Mullerian mimicry
Tracheal mites (inside honeybee)
Parasitism
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Types of Ecological Interactions
species 1 species 2 (host) Competition -/+ - Predation + - Herbivory Parasitism Disease Mutualism + +
Mutualism eg: bullhorn acacia & ants
Types of Ecological Interactions
species 1 species 2 (host) Competition +/- - Predation + - Herbivory Parasitism Disease Mutualism + + Commensalism + 0
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Commensalism eg: cattle egrets & water buffalo
Commensalism eg: epiphytic plants
Types of Ecological Interactions
species 1 species 2 (host) Competition +/- - Predation + - Herbivory Parasitism Disease Mutualism + + Commensalism + 0 Neutral 0 0
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Facilitation
Relative abundance
Species richness
Which is more diverse?
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Food web
What limits the numbers of steps/levels?
Important species in the community:
Keystone species
e.g.: ochre stars
Important species in the community:
Keystone species
e.g.: sea otters & kelp
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Important species in the community:
Foundation species
Bottom-up
Top-down
Control of relationships
Disturbance: prairie fire
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Primary succession
Secondary succession: Yellowstone 1988
Secondary succession: old Eastern US farm
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Equatorial vs.
(more diverse)
Polar gradients (less diverse)
Trees
Vertebrates
Area effects: bird species richness vs. size of island
Island biogeography & equilibrium (MacArthur & Wilson)
Actual data
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