5 Evolution and Community Ecology CHAPTER. Lesson 5.2 Species Interactions The zebra mussel has completely displaced 20 native mussel species in Lake.

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EcologyCH

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Lesson 5.2 Species Interactions

The zebra mussel has completely

displaced 20 native mussel

species in Lake St.

Clair.

The Niche

Lesson 5.2 Species Interactions

• Describes an organism’s use of resources and functional role in a community

• Affected by an organism’s tolerance—its ability to survive and reproduce under changing environmental conditions

• Often restricted by competition

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Competition• Organisms compete when they seek the same limited resource.

• In rare cases, one species can entirely exclude another from using resources.

• To reduce competition, species often partition resources, which can lead to character displacement.

Lesson 5.2 Species Interactions

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Resource Partitioning

Predation (+/–)• The process by which a

predator hunts, kills, and consumes prey

• Causes cycles in predatory and prey population sizes

• Defensive traits such as camouflage, mimicry, and warning coloration have evolved in response to predator-prey interactions.

Lesson 5.2 Species Interactions

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• Some predator-prey relationships are examples of coevolution– the process by which

two species evolve in response to changes in each other.

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Did You Know? A single rough-skinned newt contains enough poison to kill 100 people. Unfortunately for the newt, its predator, the common garter snake, has coevolved resistance to the toxin.

Did You Know? A single rough-skinned newt contains enough poison to kill 100 people. Unfortunately for the newt, its predator, the common garter snake, has coevolved resistance to the toxin.

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Parasitism and Herbivory (+/–)

Lesson 5.2 Species Interactions

Hookworm (a parasite)

• Parasitism: One organism (the parasite) relies on another (the host) for nourishment or for some other benefit

• Herbivory: An animal feeding on a plant

Did You Know? One study of Pacific estuaries suggests that parasites play an important role in keeping these ecosystems healthy by controlling host populations.

Did You Know? One study of Pacific estuaries suggests that parasites play an important role in keeping these ecosystems healthy by controlling host populations.

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Mutualism (+/+) and Commensalism (+/0)

Lesson 5.2 Species Interactions

• Mutualism: a relationship in which two or more species benefit

• Commensalism: a relationship in which one species benefits while the other is unaffected

Lichen: a symbiotic relationship between a fungus and a photosynthetic partner, such as an alga

Did You Know? Symbiosis describes a long-lasting and physically close relationship between species in which at least one species benefits.

Did You Know? Symbiosis describes a long-lasting and physically close relationship between species in which at least one species benefits.

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Mutualism

Commensalism

• http://www.youtube.com/watch?v=8YKAalZAqO4 Rhino song

• http://www.youtube.com/watch?v=uxVMeLWzB_o