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Chapter 14:

Interactions in Ecosystems

14.1 Main Idea--

 Habitat and Niche

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14.1 What is an Ecological Niche?

 NICHE  …the role an

organism has in an ecosystem, or the way an organism lives.

 Lion – Text 429  handout 365 -

look at jaguar’s niche.

 Habitat is a where a species lives

 Niche is HOW a species lives

 Food  Abiotic Conditions  Behavior

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Competitive Exclusion

 Game On! There will be a winner and a loser-

 when one species is forced out of an ecosystem due to being out-competed. Main Idea –

Habitat and Niche

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SG #4 (front of pg 4)

 Three Possible Outcomes of Competitive Exclusion  Example- Text 429

1) One adapts – one dies 2)  Adapt- Niche Partitioning 3)  Both Adapt – Coevolution

or Divergent Evolution

Video clip

 Biologix, show begin to predation 12:48ish

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When does competition occur?

 COMPETITION OCCURS WHEN SPECIES’ NICHES OVERLAP AND RESOURCES ARE LIMITED!

 Handout! from Holt “Size of a

Species Niche”

- Copy challenges… 365, 367, 366

Fundamental Niche

 the entire range of resource opportunities within an ecosystem–

 includes any possible resources the species could use.

 Warbler Example: Several warbler species eat insects from spruce trees in NE US and Canada.

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Classic Warbler Niche Example

 What would happen if all five species tried to occupy the same niche?

 Competitive

Exclusion would force all but one species out of the area.

Realized Niche  The realized niche is the segment

of the fundamental niche that the species actually occupies.

 While a species may have a large fundamental niche (where it could be), it could have a relatively small realized niche (where it chooses to be)

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Warbler Competition

 What does the behavior of the warblers do to the competition among them?

 It reduces the competition

among these birds and allows them to coexist

Warbler Example – Realized Niche

Each of the five species of warblers has it’s own realized niche. (Each feeds at a different place in the spruce trees.)

Color highlight these zones on the handout

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What happens when organisms

compete for resources?

 Eventually, one will out-compete the other.

 The species affected will have to migrate, adapt, or be crowded out.

 See inset pg. 367

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How do predators affect competition?

 Predators reduce competition by taking out some organisms of a species. This leads to an increase in biodiversity.

Activities

DUE next block

 Invasive WQ  Finish Threats to Biodiversity  In your packet: 14.1 SG