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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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